Deep Learning Model for Tumor Type Prediction using Targeted Clinical Genomic Sequencing Data

Tumor type guides clinical treatment decisions in cancer, but histology-based diagnosis remains challenging. Genomic alterations are highly diagnostic of tumor type, and tumor type classifiers trained on genomic features have been explored, but the most accurate methods are not clinically feasible, relying on features derived from whole genome sequencing (WGS), or predicting across limited cancer types. We use genomic features from a dataset of 39,787 solid tumors sequenced using a clinical targeted cancer gene panel to develop Genome-Derived-Diagnosis Ensemble (GDD-ENS): a hyperparameter ensemble for classifying tumor type using deep neural networks. GDD-ENS achieves 93% accuracy for high-confidence predictions across 38 cancer types, rivalling performance of WGS-based methods. GDD-ENS can also guide diagnoses on rare type and cancers of unknown primary, and incorporate patient-specific clinical information for improved predictions. Overall, integrating GDD-ENS into prospective clinical sequencing workflows could provide clinically-relevant tumor type predictions to guide treatment decisions in real time.

Favorable Survival after Definitive Ablative RT in Surgically Resectable Pancreatic Cancer Patients

PURPOSE/OBJECTIVE(S)

Surgical resection has been considered the only curative option for patients with pancreatic adenocarcinoma (PDAC). Ablative RT ≥100Gy BED10 (A-RT) is associated with favorable survival in patients with locally advanced unresectable disease. We sought to evaluate A-RT outcomes in patients with technically resectable disease who did not undergo surgery.

MATERIALS/METHODS

Our prospectively maintained database of patients treated with A-RT was queried for consecutive patients with radiographic T1/T2 resectable PDAC. Patients were treated with a standardized technique within a large academic cancer center regional network. Ablative RT using several hypofractionated regimens was delivered on either standard Linacs with respiratory motion management, CBCT image guidance and selective adaptive replanning or MR-Linac with compression belt and daily on-line adaptive replanning. Freedom from local progression (FFLP), distant metastasis-free and overall survival (DMFS and OS, respectively) were analyzed using the Kaplan Meier estimates.

RESULTS

Between 2016 and 2022, 28 patients (54% male) with radiographically resectable PDAC received definitive A-RT. Median age was 80 (interquartile range, 77-84) years and 23 (82.1%) had KPS of 80 or below. Eighteen patients (64.3%) had T2 cancer, 5 (17.9%) were node positive, and 23 (82.1%) had head location. Median size was 2.6 (range, 1.6-4.0) cm with a median carbohydrate antigen 19-9 (CA19-9) of 160.5 (0-1823) U/mL. Twenty patients (71.4%) received induction chemotherapy for a median of 2.4 (0-6.2) months. RT regimens delivered on conventional Linacs unless otherwise indicated included 75Gy in 25 fractions (n = 15), 67.5Gy in 15 fractions (n = 10), 50Gy in 5 (N = 2, MR Linac), 60Gy in 10 (n = 1). 24-month FFLP and DMFS were 78.8% (52.3-91.7%) and 17.7% (95% CI, 5.8%-34.8%), respectively. 24-month and 48-month rate of OS from A-RT were 49.1% (95% CI, 27.53-67.5%) and 36.3 (95%16.0-57.1%). Grade 3 acute and late GI toxicity was noted in 3 and 1 patients, respectively, including 2 bleeding events treated with transfusions. There were no ≥ grade 4 events.

CONCLUSION

In patients with surgically resectable PDAC we found that definitive A-RT following multiagent induction therapy was associated with oncologic outcomes similar to resection with minimal toxicity.

Deep Learning Model for Tumor Type Prediction using Targeted Clinical Genomic Sequencing Data

Tumor type guides clinical treatment decisions in cancer, but histology-based diagnosis remains challenging. Genomic alterations are highly diagnostic of tumor type, and tumor type classifiers trained on genomic features have been explored, but the most accurate methods are not clinically feasible, relying on features derived from whole genome sequencing (WGS), or predicting across limited cancer types. We use genomic features from a dataset of 39,787 solid tumors sequenced using a clinical targeted cancer gene panel to develop Genome-Derived-Diagnosis Ensemble (GDD-ENS): a hyperparameter ensemble for classifying tumor type using deep neural networks. GDD-ENS achieves 93% accuracy for high-confidence predictions across 38 cancer types, rivalling performance of WGS-based methods. GDD-ENS can also guide diagnoses on rare type and cancers of unknown primary, and incorporate patient-specific clinical information for improved predictions. Overall, integrating GDD-ENS into prospective clinical sequencing workflows has enabled clinically-relevant tumor type predictions to guide treatment decisions in real time.

Personalized RNA neoantigen vaccines stimulate T cells in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is lethal in 88% of patients1, yet harbours mutation-derived T cell neoantigens that are suitable for vaccines 2,3. Here in a phase I trial of adjuvant autogene cevumeran, an individualized neoantigen vaccine based on uridine mRNA-lipoplex nanoparticles, we synthesized mRNA neoantigen vaccines in real time from surgically resected PDAC tumours. After surgery, we sequentially administered atezolizumab (an anti-PD-L1 immunotherapy), autogene cevumeran (a maximum of 20 neoantigens per patient) and a modified version of a four-drug chemotherapy regimen (mFOLFIRINOX, comprising folinic acid, fluorouracil, irinotecan and oxaliplatin). The end points included vaccine-induced neoantigen-specific T cells by high-threshold assays, 18-month recurrence-free survival and oncologic feasibility. We treated 16 patients with atezolizumab and autogene cevumeran, then 15 patients with mFOLFIRINOX. Autogene cevumeran was administered within 3 days of benchmarked times, was tolerable and induced de novo high-magnitude neoantigen-specific T cells in 8 out of 16 patients, with half targeting more than one vaccine neoantigen. Using a new mathematical strategy to track T cell clones (CloneTrack) and functional assays, we found that vaccine-expanded T cells comprised up to 10% of all blood T cells, re-expanded with a vaccine booster and included long-lived polyfunctional neoantigen-specific effector CD8+ T cells. At 18-month median follow-up, patients with vaccine-expanded T cells (responders) had a longer median recurrence-free survival (not reached) compared with patients without vaccine-expanded T cells (non-responders; 13.4 months, P = 0.003). Differences in the immune fitness of the patients did not confound this correlation, as responders and non-responders mounted equivalent immunity to a concurrent unrelated mRNA vaccine against SARS-CoV-2. Thus, adjuvant atezolizumab, autogene cevumeran and mFOLFIRINOX induces substantial T cell activity that may correlate with delayed PDAC recurrence.

Genomic Biomarkers Associated with Response to Induction Chemotherapy in Patients with Localized Pancreatic Ductal Adenocarcinoma

PURPOSE

There is increasing use of neoadjuvant chemotherapy in the management of localized pancreatic ductal adenocarcinoma (PDAC), yet there are few validated biomarkers to guide therapy selection. We aimed to determine whether somatic genomic biomarkers predict response to induction FOLFIRINOX or gemcitabine/nab-paclitaxel.

EXPERIMENTAL DESIGN

This single-institution cohort study included consecutive patients (N = 322) with localized PDAC (2011-2020) who received at least one cycle of FOLFIRINOX (N = 271) or gemcitabine/nab-paclitaxel (N = 51) as initial treatment. We assessed somatic alterations in four driver genes (KRAS, TP53, CDKN2A, and SMAD4) by targeted next-generation sequencing, and determined associations between these alterations and (1) rate of metastatic progression during induction chemotherapy, (2) surgical resection, and (3) complete/major pathologic response.

RESULTS

The alteration rates in driver genes KRAS, TP53, CDKN2A, and SMAD4 were 87.0%, 65.5%, 26.7%, and 19.9%, respectively. For patients receiving first-line FOLFIRINOX, SMAD4 alterations were uniquely associated with metastatic progression (30.0% vs. 14.5%; P = 0.009) and decreased rate of surgical resection (37.1% vs. 66.7%; P < 0.001). For patients receiving induction gemcitabine/nab-paclitaxel, alterations in SMAD4 were not associated with metastatic progression (14.3% vs. 16.2%; P = 0.866) nor decreased rate of surgical resection (33.3% vs. 41.9%; P = 0.605). Major pathologic response was rare (6.3%) and not associated with type of chemotherapy regimen.

CONCLUSIONS

SMAD4 alterations were associated with more frequent development of metastasis and lower probability of reaching surgical resection during neoadjuvant FOLFIRINOX but not gemcitabine/nab-paclitaxel. Confirmation in a larger, diverse patient cohort will be important before prospective evaluation of SMAD4 as a genomic biomarker to guide treatment selection.

Phase II trial of maximal ablative irradiation because of encasement (MAIBE) for patients with potentially resectable locally advanced pancreatic cancer

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Background: For patients with localized but not immediately resectable pancreatic adenocarcinoma (PDAC), the role for local therapy remains undefined. Phase II MAIBE trial studied ablative radiation (A-RT) followed by consideration of surgery for patients with locally advanced pancreatic cancer (LAPC) who remain unresectable after induction chemotherapy. Methods: Participants with histologically confirmed PDAC judged unresectable by multidisciplinary review using NCCN definition after completing 3-6 months of mFOLFIRINOX (FFX) or Gemcitabine/Nab-paclitaxel (GN) were eligible. They received hypofractionated A-RT (either 67.5Gy in 15 fractions or 75Gy in 25 fractions based on anatomy) with concurrent capecitabine followed by consideration of resection within 1-3 months. Primary endpoints included resectability (80% power to detect resectability improvement from 15% in historical controls to 30% with α = 0.05) and overall survival (OS) from A-RT. Secondary endpoints included safety of surgical resection after ablative RT using 90-day Clavien-Dindo Classification of adverse events (AE). Results: Between 6/2018 and 4/2022, 47 eligible participants underwent A-RT. Median age was 67 (range, 50-80) years, 24 (51%) were male with a median tumor size of 3.95 (1.6 – 8.3) cm and CA19-9 of 92 ( < 1-1601) U/mL. Forty-four patients (94%) received at least 1 cycle of FFX with a median duration of chemotherapy (FFX or GN) of 3.5 months (1.0 – 9.4). Sixteen (34%) underwent a laparoscopy and 12 (26%) underwent a resection (Pancreaticoduodenectomy, N = 11; distal pancreatectomy, N = 1) at a median time of 3.2 months (1.9-16.9 months) from start of A-RT. The rate of resection satisfied our prespecified boundary of 11. R0 rate was 58.3%. Two-year OS from A-RT for the entire cohort was 38.9% (95% CI, 21.9 – 55.6%), including 37.1% (18.5 - 55.8%) in non-surgical and 39.4% (7.0- 72.1%) in surgical groups. There were no deaths within 90 days of surgery and 9 surgical AEs were recorded in 6 participants, including grade 1 (n = 1), grade 2 (n = 5), grade 3 (n = 2) and grade unknown (n = 1). Conclusions: In patients with LAPC and no metastatic disease after 3-6 months of chemotherapy, A-RT results in a favorable rate of resection without excess surgical toxicity. Promising 2-year OS rates were noted in both resected and non-resected patients. Clinical trial information: NCT03523312 .

A phase II study of durvalumab and stereotactic ablative body radiotherapy (SABR) in locally advanced pancreatic adenocarcinoma (LA PDAC)

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Background: Immune checkpoint blockade (ICB) has a modest signal in the treatment of patients with genomically unselected pancreatic cancer (PDAC). Synergistic effects of combined radiotherapy and ICB are postulated. Preliminary results of a phase 1/2 trial of anti-PD-L1 antibody durvalumab (D) and SABR in locally advanced (LA) and borderline resectable PDAC (Tuli, AACR; 2019; Abstr B58), noted SABR and D to be safe and tolerable following induction chemotherapy. We sought to further evaluate the tolerability and efficacy of D and SABR, in LA PDAC. Methods: A single-arm, open-label phase 2 trial was conducted at Memorial Sloan Kettering (MSK). Key eligibility: histologically confirmed LA unresectable PDAC, with stable or responding disease following 4-6 months (m) of FOLFIRINOX (FFX), ECOG 0-2. Therapy: D and SABR; D dosed on day 1 750mg x 4 doses Q14 days, and subsequently 1500mg Q 28 days x 11 doses (1 year total), or until progression of disease (POD), or limiting toxicity. All patients received MRI adaptive ablative radiation, 50Gy in 5 fractions between doses 1 and 2 of D. Primary endpoint: 6-m progression free survival (6 m PFS) by RECIST v1.1. Secondary endpoints were Duration of Response, Overall Response Rate (ORR), CA 19-9 response, rates of downstaging/resection, and survival outcomes (overall survival (OS) and progression-free survival (PFS)) calculated from date of enrolment. OS and PFS were estimated using Kaplan-Meier method. Pre- and on-treatment tissue, blood and microbiome samples were collected to evaluate tumor-intrinsic and peripheral immunogenomic correlates of response. Results: Between 09/2020 and 05/2022, N = 18 enrolled. Median age 67.5 years (IQR; 62.5, 71.5), 28% (5/18) female. Baseline Performance Status: N = 8 (44%) ECOG 0; N = 10 (56%) ECOG 1. Tumor location: Head/uncinate N = 9 (50%), body N = 7 (39%), neck N = 2 (11%). Median # doses FFX prior to enrolment: 8.5 (IQR; 8.0- 11.0). At median follow-up of 13.8 m, 6-m PFS: 62% (95% CI 43%, 91%). Median PFS: 10.2 m (95% CI; 5.03, NA) and median OS 17.2 m (95% CI; 12.98, NA). Disease progression (any time) N = 12, of which local POD in N = 7 (58%). N = 3 completed maintenance D; N = 5 on active treatment. ORR: N = 17 (94.4%) stable disease (95% CI; 64.6%, 99.4%). Toxicity endpoints of special interest: Grade 3 ICB-related: in N = 4 patients; diarrhea N = 2; elevated AST/ALT N = 2; G3 lipase elevation N = 1; attribution uncertain. Conclusions: D and SABR following FFX in LA PDAC had an encouraging 6-m PFS of 62% (43-91%) and a tolerable safety profile. Immuno-genomic analyses of correlative biospecimens is underway. Funding support AstraZeneca. Clinical trial information: NCT03245541 .

Adjuvant modified FOLFIRINOX (mFFX) for resected pancreatic cancer (PDAC): Real world outcomes (RWO)

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Background: Adjuvant mFFX (5-fluorouracil, leucovorin, irinotecan, oxaliplatin) is a standard-of-care for fit patients (pts) with resected PDAC, owing to the immediate practice-changing PRODIGE 24/CCTG PA6 trial (2018). Five-year follow-up: median overall survival (mOS) 53.3 months (m) and median disease-free survival (mDFS) 21.4 m for mFFX vs 35.5 m and 12.8 m for gemcitabine (Conroy, JAMA Onc, 2022). RWO for pts outside a clinical trial are lacking. Herein, we report RWO for pts with resected PDAC and intent for adjuvant mFFX at Memorial Sloan Kettering (MSK). Methods: Institutional databases were queried to identify pts with resected PDAC who received any dose of adjuvant mFFX. Demographic, clinicopathologic, genomic, dosing details, and survival data were abstracted from medical and pharmacy records. Primary endpoint was to determine recurrence-free survival (RFS) calculated from start date mFFX to disease recurrence or death and OS calculated from start date mFFX to death. Secondary endpoints included dose reductions, significant treatment delay, toxicity profile, patterns of failure, genomic associations with outcome. RFS and OS are estimated using the Kaplan-Meier method. Study approved by MSK IRB. Results: N = 114 pts with resected PDAC treated with mFFX (> 1 dose) identified between 01/2015- 01/2022. Median age: 67 years (range 35 to 82); N = 43 (38%) > 70 years, N = 18 (16%) > 75 years, N = 2 (2%) > 80 years. Baseline Performance Status recorded in N = 104: N = 31 (30%) ECOG 0, N = 64 (62%) ECOG 1, N = 9 (9%) ECOG 2. Disease stage: N = 36 (32%) stage III, N = 61 (54%) stage II, and N = 17 (15%) pts stage I. Resection status: N = 91 (80%) R0, N = 23 (20%) R1. Presence of lymphovascular invasion: N = 92 (81%), perineural invasion N = 106 (93%). Median baseline CA 19-9: 20 U/mL (IQR; 9, 38). Median follow up: 22.4 m (range 6.2, 50.4). Median time from surgery to start mFFX: 7.4 weeks (IQR; 6.1, 9.3). Median # of mFFX doses received: 12 (IQR; 12, 12), N = 90 (79%) pts completed 12 doses. Dosing details available N = 112. N = 55 (49%) prescribed less than full dose of > one drug at baseline. Dose reductions: N = 57 (51%). N = 69 (62%) received < 12 doses oxaliplatin. N = 97 (87%) received growth factor support. mRFS: 31 m (95% CI; 23, Not Reached). N = 18 (16%) were hospitalized for treatment related adverse events, no therapy related mortality. N = 24 (21%) received adjuvant radiation therapy. One-year OS rate: 93% (95% CI; 89%, 98%) and 2-year OS rate: 78% (95%CI: 70%, 88%). Among patients with recurrence (N = 44), most common sites of first recurrence were: liver (N = 18, 41%), local (N = 14, 32%), and lung (N = 9, 20%). Conclusions: These data endorse mFFX as standard therapy for resected PDAC. The survival signals are encouraging in a prognostically unfavorable albeit select patient population (relative to PRODIGE 24). Dose adjustments to facilitate optimizing tolerability is key. Additional genomic and subtype analyses are underway.

Clinico-genomic Characterization of ATM and HRD in Pancreas Cancer: Application for Practice

PURPOSE

Characterizing germline and somatic ATM variants (gATMm, sATMm) zygosity and their contribution to homologous recombination deficiency (HRD) is important for therapeutic strategy in pancreatic ductal adenocarcinoma (PDAC).

EXPERIMENTAL DESIGN

Clinico-genomic data for patients with PDAC and other cancers with ATM variants were abstracted. Genomic instability scores (GIS) were derived from ATM-mutant cancers and overall survival (OS) was evaluated.

RESULTS

Forty-six patients had PDAC and pathogenic ATM variants including 24 (52%) stage III/IV: gATMm (N = 24), and sATMm (N = 22). Twenty-seven (59%) had biallelic, 15 (33%) monoallelic, and 4 indeterminate (8%) variants. Median OS for advanced-stage cohort at diagnosis (N = 24) was 19.7 months [95% confidence interval (CI): 12.3-not reached (NR)], 27.1 months (95% CI: 22.7-NR) for gATMm (n = 11), and 12.3 months for sATMm (n = 13; 95% CI: 11.9-NR; P = 0.025). GIS was computed for 33 patients with PDAC and compared with other ATM-mutant cancers enriched for HRD. The median was lower (median, 11; range, 2-29) relative to breast (18, 3-55) or ovarian (25, 3-56) ATM-mutant cancers (P < 0.001 and P = 0.003, respectively). Interestingly, biallelic pathogenic ATM variants were mutually exclusive with TP53. Other canonical driver gene (KRAS, CDKN2A, SMAD4) variants were less frequent in ATM-mutant PDAC.

CONCLUSIONS

ATM variants in PDAC represent a distinct biologic group and appear to have favorable OS. Nonetheless, pathogenic ATM variants do not confer an HRD signature in PDAC and ATM should be considered as a non-core HR gene in this disease.

Circulating tumor and invasive cell expression profiling predicts effective therapy in pancreatic cancer

BACKGROUND

Pancreatic adenocarcinoma (PDAC) remains a refractory disease; however, modern cytotoxic chemotherapeutics can induce tumor regression and extend life. A blood-based, pharmacogenomic, chemosensitivity assay using gene expression profiling of circulating tumor and invasive cells (CTICs) to predict treatment response was previously developed. The combination regimen of 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) and gemcitabine/nab-paclitaxel (G/nab-P) are established frontline approaches for treating advanced PDAC; however, there are no validated biomarkers for treatment selection. A similar unmet need exists for choosing second-line therapy.

METHODS

The chemosensitivity assay was evaluated in metastatic PDAC patients presenting for frontline treatment. A prospective study enrolled patients (n = 70) before receiving either FOLFIRINOX or G/nab-P at a 1:1 ratio. Six milliliters of peripheral blood was collected at baseline and at time of disease progression. CTICs were isolated, gene-expression profiling was performed, and the assay was used to predict effective and ineffective chemotherapeutic agents. Treating physicians were blinded to the assay prediction results.

RESULTS

Patients receiving an effective regimen as predicted by the chemosensitivity assay experienced significantly longer median progression-free survival (mPFS; 7.8 months vs. 4.2 months; hazard ratio [HR], 0.35; p = .0002) and median overall survival (mOS; 21.0 months vs. 9.7 months; HR, 0.40; p = .005), compared with an ineffective regimen. Assay prediction for effective second-line therapy was explored. The entire study cohort experienced favorable outcomes compared with historical controls, 7.1-month mPFS and 12.3-month mOS.

CONCLUSIONS

Chemosensitivity assay profiling is a promising tool for guiding therapy in advanced PDAC. Further prospective validation is under way (clinicaltrials.gov NCT03033927).

Immunogenomic characterization of biliary tract cancers: Biomarker enrichment for benefit to immune checkpoint blockade

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Background: Several immunomodulatory molecules (PD-L1, B7H4, and CD276) have been associated with biliary tract cancer (BTC) subgroups, suggesting potential value to immune checkpoint blockade (ICB) in this lethal disease. Phase II monotherapy (pembrolizumab or nivolumab), and combination (atezolizumab and cobimetinib) ICB trials reported low response rates in unselected advanced BTC with a wide range of responses. A recent randomized phase III trial (TOPAZ-1) reported an overall survival (OS) benefit among patients (pts) with advanced BTC treated with chemotherapy and anti-PD-L1 ICB. However, no correlation between PD-L1 expression and OS was noted and biomarker enrichment strategy in BTC for immunotherapy remains a key to optimize OS. Methods: From our comprehensive clinico-genomic database for BTC at Memorial Sloan Kettering (MSK), a retrospective genomic landscape and neoantigen analysis was performed using MSK-IMPACT. Potential immunogenic subgroups were evaluated: homologous recombination deficiency (HRD) defined by pathogenic alterations in BRCA1/2, PALB2, and BAP1, microsatellite stability high (MSI-H) defined by MSIsensor score ≥10, and tumor mutation burden (TMB)>10. Clinical outcomes with anti-PD-1 ICB were evaluated. Results: Among N=1,190 pts with BTC, N=1,346 samples were sequenced between 03/2014 and 01/2022. Key actionable alterations included (%): IDH1, 2 (13, 3), FGFR2 fusions (9), ERBB2 amplification (5), BRAF V600E (2), RNF43 (2), POLE (2), NTRK1 fusion (<1). There were N=230 (17%) patients with putatively more immunogenic BTC (iBTC) identified by HRD [ BRCA1/2 (1, 2.4), PALB2 (1), BAP1 (9)], TMB>10, and MSI-H. Frequency, location (intrahepatic, ICC; extrahepatic, ECC; gallbladder, GBC), TMB, and genomic instability score (GIS) are summarized (Table). Among iBTC subgroup, N=32 pts received ICB. Their median follow up was 29.1 months. Median lines of prior therapy was 3. Median PFS was 5.6 M (95%CI: 1.2-10.1) and OS was 33.4 M (23.1-43.6). Conclusion: A subgroup of BTC pts (iBTC) benefit from ICB. Apart from MSI-H and TMB>10, other genomically-defined subgroups such as HRD may benefit from ICB. Prospective studies are needed to evaluate a better biomarker enrichment strategy beyond PD-L1 and TMB, that can represent other immunogenic aspects of tumor neoantigen and microenvironment. [Table: see text]

Induction FOLFIRINOX for patients with locally unresectable pancreatic ductal adenocarcinoma

OBJECTIVES

Patients with locally advanced pancreatic adenocarcinoma (PDAC) receive induction chemotherapy with or without radiation, with the goal of R0 resection and improving survival. Herein, we evaluate the outcomes of patients who presented with Stage III PDAC and received induction FOLFIRINOX.

METHODS

An institutional database was queried for consecutive patients who received induction FOLFIRINOX for locally unresectable PDAC between 2010 and 2016. Clinical and radiographic parameters were assessed pre- and posttreatment, and clinical outcomes were evaluated.

RESULTS

There were 200 patients who met the inclusion criteria. The median number of cycles of FOLFIRINOX was 8, 70% (n = 140) received radiation, and 18% (n = 36) underwent resection. Median overall survival (OS) in resected patients was 36 months (95% confidence interval [CI]: 24-56), and this group had improved OS compared to patients that did not undergo resection (hazard ratio (95% CI): 0.41 (0.26-0.64), p < 0.001). Patients (n = 112) who did not progress on induction therapy but remained unresectable had a median OS of 23.9 months (95% CI: 21.1-25.4).

CONCLUSION

Nearly 20% of patients with locally advanced PDAC responded sufficiently to induction FOLFIRINOX to undergo resection, which was associated with improved OS compared to patients that did not undergo resection. Patients with stable disease who remain unresectable represent a group of patients with locally advanced PDAC who may benefit from optimization of additional nonoperative treatment.

Genomic characterization of metastatic patterns from prospective clinical sequencing of 25,000 patients

Metastatic progression is the main cause of death in cancer patients, whereas the underlying genomic mechanisms driving metastasis remain largely unknown. Here, we assembled MSK-MET, a pan-cancer cohort of over 25,000 patients with metastatic diseases. By analyzing genomic and clinical data from this cohort, we identified associations between genomic alterations and patterns of metastatic dissemination across 50 tumor types. We found that chromosomal instability is strongly correlated with metastatic burden in some tumor types, including prostate adenocarcinoma, lung adenocarcinoma, and HR+/HER2+ breast ductal carcinoma, but not in others, including colorectal cancer and high-grade serous ovarian cancer, where copy-number alteration patterns may be established early in tumor development. We also identified somatic alterations associated with metastatic burden and specific target organs. Our data offer a valuable resource for the investigation of the biological basis for metastatic spread and highlight the complex role of chromosomal instability in cancer progression.

Methylation Analyses Reveal Promoter Hypermethylation as a Rare Cause of "Second Hit" in Germline BRCA1-Associated Pancreatic Ductal Adenocarcinoma

BACKGROUND AND OBJECTIVE

Pancreatic ductal adenocarcinoma (PDAC) is characterized by the occurrence of pathogenic variants in BRCA1/2 in 5-6% of patients. Biallelic loss of BRCA1/2 enriches for response to platinum agents and poly (ADP-ribose) polymerase 1 inhibitors. There is a dearth of evidence on the mechanism of inactivation of the wild-type BRCA1 allele in PDAC tumors with a germline BRCA1 (gBRCA1) pathogenic or likely pathogenic variant (P/LPV). Herein, we examine promotor hypermethylation as a "second hit" mechanism in patients with gBRCA1-PDAC.

METHODS

We evaluated patients with PDAC who underwent Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) somatic and germline testing from an institutional database. DNA isolated from tumor tissue and matched normal peripheral blood were sequenced by MSK-IMPACT. In patients with gBRCA1-PDAC, we examined the somatic BRCA1 mutation status and promotor methylation status of the tumor BRCA1 allele via a methylation array analysis. In patients with sufficient remaining DNA, a second methylation analysis by pyrosequencing was performed.

RESULTS

Of 1012 patients with PDAC, 19 (1.9%) were identified to harbor a gBRCA1 P/LPV. Fifteen patients underwent a methylation array and the mean percentage of BRCA1 promotor methylation was 3.62%. In seven patients in whom sufficient DNA was available, subsequent pyrosequencing confirmed an unmethylated BRCA1 promotor. Loss of heterozygosity was detected in 12 of 19 (63%, 95% confidence interval 38-84) patients, demonstrating loss of heterozygosity is the major molecular mechanism of BRCA1 inactivation in PDAC. Two (10.5%) cases had a somatic BRCA1 mutation.

CONCLUSIONS

In patients with gBRCA1-P/LPV-PDAC, loss of heterozygosity is the main inactivating mechanism of the wild-type BRCA1 allele in the tumor, and methylation of the BRCA1 promoter is a distinctly uncommon occurrence.

Local Control and Survival After Induction Chemotherapy and Ablative Radiation Versus Resection for Pancreatic Ductal Adenocarcinoma With Vascular Involvement

OBJECTIVE

We sought to compare overall survival (OS) and disease control for patients with localized pancreatic ductal adenocarcinoma (PDAC) treated with ablative dose radiotherapy (A-RT) versus resection.

SUMMARY BACKGROUND DATA

Locoregional treatment for PDAC includes resection when possible or palliative RT. A-RT may offer durable tumor control and encouraging survival.

METHODS

This was a single-institution retrospective analysis of patients with PDAC treated with induction chemotherapy followed by A-RT [≥98 Gy biologically effective dose (BED) using 15-25 fractions in 3-4.5 Gy/fraction] or pancreatectomy.

RESULTS

One hundred and four patients received A-RT (49.8%) and 105 (50.2%) underwent resection. Patients receiving A-RT had larger median tumor size after induction chemotherapy [3.2 cm (undetectable-10.9) vs 2.6 cm (undetectable-10.7), P < 0.001], and were more likely to have celiac or hepatic artery encasement (48.1% vs 11.4%, P <0.001), or superior mesenteric artery encasement (43.3% vs 9.5%, P < 0.001); however, there was no difference in the degree of SMV/PV involvement (P = 0.123). There was no difference in locoregional recurrence/progression at 18-months between A-RT and resection; cumulative incidence was 16% [(95% confidence interval (CI) 10%-24%] versus 21% (95% CI 14%-30%), respectively (P= 0.252). However, patients receiving A-RT had a 19% higher 18-month cumulative incidence of distant recurrence/progression [58% (95% CI 48%-67%) vs 30% (95% CI 30%-49%), P= 0.004]. Median OS from completion of chemotherapy was 20.1 months for A-RT patients (95% CI 16.4-23.1 months) versus 32.9 months (95% CI 29.7-42.3 months) for resected patients (P < 0.001).

CONCLUSION

Ablative radiation is a promising new treatment option for PDAC, offering locoregional disease control similar to that associated with resection and encouraging survival.

Nasopharyngeal colonization of otopathogens in South Indian children with acute otitis media - A case control pilot study

Background

Acute otitis media (AOM) is an inflammatory disease of the middle ear causing significant morbidity in early childhood. A pilot study was undertaken to identify the role of various risk factors South Indian children with AOM, especially the role of nasopharyngeal otopathogens.

Methodology

A prospective case control pilot study was conducted in children aged below six years, presenting to a single tertiary care from 2018 to 2019. Fifty cases with AOM and 45 age and gender matched controls were recruited. Two nasopharyngeal swabs were collected, one was processed for bacterial culture. The other swab was processed according to the CDC recommended broth enrichment method to identify carriage of S. pneumoniae. Subsequent serotyping was done by Quellung method and conventional sequential multiplex PCR.

Result

Otalgia was the major presentation seen in 92% of the children with AOM. None of the clinical and demographic characteristics were found to be statistically significant between the cases and controls. The most common otopathogen was S. pneumoniae (55%) followed by H. influenza (29%). The common S. pneumoniae serotypes encountered were 11A and 19F.Nasopharyngeal colonization with S. pneumoniae [OR 6.57, p < 0.003] and H. influenzae [OR14.18, p < 0.003] were significant risk factors for AOM in children. The risk increased with co-colonization (OR 13.89,p < 0.003).

Conclusion

This study strengthens the significant association between nasopharyngeal colonization of otopathogens and AOM as a risk factor that is enhanced by co-colonization.S. pneumoniae was the main otopathogen in this population, serotypes 11A and 19F being the most common.

Early-Onset Pancreas Cancer: Clinical Descriptors, Genomics, and Outcomes

BACKGROUND

Recent evidence suggests a rising incidence of cancer in younger individuals. Herein, we report the epidemiologic, pathologic, and molecular characteristics of a patient cohort with early-onset pancreas cancer (EOPC).

METHODS

Institutional databases were queried for demographics, treatment history, genomic results, and outcomes. Overall survival from date of diagnosis was estimated using Kaplan-Meier method.

RESULTS

Between 2008 and 2018, 450 patients with EOPC were identified at Memorial Sloan Kettering. Median overall survival was 16.3  (95% confidence interval [CI] = 14.6 to 17.7) months in the entire cohort and 11.3  (95% CI = 10.2 to 12.2) months for patients with stage IV disease at diagnosis. Of the patients, 132 (29.3% of the cohort) underwent somatic testing; 21 of 132 (15.9%) had RAS wild-type cancers with identification of several actionable alterations, including ETV6-NTRK3, TPR-NTRK1, SCLA5-NRG1, and ATP1B1-NRG1 fusions, IDH1 R132C mutation, and mismatch repair deficiency. A total of 138 patients (30.7% of the cohort) underwent germline testing; 44 of 138 (31.9%) had a pathogenic germline variant (PGV), and 27.5% harbored alterations in cancer susceptibility genes. Of patients seen between 2015 and 2018, 30 of 193 (15.5%) had a PGV. Among 138 who underwent germline testing, those with a PGV had a reduced all-cause mortality compared with patients without a PGV controlling for stage and year of diagnosis (hazard ratio = 0.42, 95% CI = 0.26 to 0.69).

CONCLUSIONS

PGVs are present in a substantial minority of patients with EOPC. Actionable somatic alterations were identified frequently in EOPC, enriched in the RAS wild-type subgroup. These observations underpin the recent guidelines for universal germline testing and somatic profiling in pancreatic ductal adenocarcinoma.

Pancreas cancer and BRCA: A critical subset of patients with improving therapeutic outcomes

BACKGROUND

Patients with germline/somatic BRCA1/BRCA2 mutations (g/sBRCA1/2) comprise a distinct biologic subgroup of pancreas ductal adenocarcinoma (PDAC).

METHODS

Institutional databases were queried to identify patients who had PDAC with g/sBRCA1/2. Demographics, clinicopathologic details, genomic data (annotation sBRCA1/2 according to a precision oncology knowledge base for somatic mutations), zygosity, and outcomes were abstracted. Overall survival (OS) was estimated using the Kaplan-Meier method.

RESULTS

In total, 136 patients with g/sBRCA1/2 were identified between January 2011 and June 2020. Germline BRCA1/2 (gBRCA1/2) mutation was identified in 116 patients (85%). Oncogenic somatic BRCA1/2 (sBRCA1/2) mutation was present in 20 patients (15%). Seventy-seven patients had biallelic BRCA1/2 mutations (83%), and 16 (17%) had heterozygous mutations. Sixty-five patients with stage IV disease received frontline platinum therapy, and 52 (80%) had a partial response. The median OS for entire cohort was 27.6 months (95% CI, 24.9-34.5 months), and the median OS for patients who had stage IV disease was 23 months (95% CI, 19-26 months). Seventy-one patients received a poly(adenosine diphosphate ribose) polymerase (PARP) inhibitor (PARPi), and 52 received PARPi monotherapy. For maintenance PARPi, 10 patients (36%) had a partial response, 12 (43%) had stable disease, and 6 (21%) had progression of disease as their best response. Six patients (21%) received maintenance PARPi for >2 years. For those with stage IV disease who received frontline platinum, the median OS was 26 months (95% CI, 20-52 months) for biallelic patients (n = 39) and 8.66 months (95% CI, 6.2 months to not reached) for heterozygous patients (n = 4). The median OS for those who received PARPi therapy was 26.5 months (95% CI, 24-53 months) for biallelic patients (n = 25) and 8.66 months (95% CI, 7.23 months to not reached) for heterozygous patients (n = 2).

CONCLUSIONS

g/sBRCA1/2 mutations did not appear to have different actionable utility. Platinum and PARPi therapies offer therapeutic benefit, and very durable outcomes are observed in a subset of patients who have g/sBRCA1/2 mutations with biallelic status.

Treatment patterns and survival in patients with early-onset pancreatic cancer

BACKGROUND

Pancreatic cancer is uncommon in patients younger than 50 years, although its incidence is increasing. This study characterizes treatment utilization for early-onset pancreatic cancer (EOPC) versus average-age-onset pancreatic cancer (AOPC) and identifies factors associated with failure to receive treatment.

METHODS

The National Cancer Data Base (NCDB) was queried for patients with EOPC (age < 50 years) or AOPC (age ≥ 50 years) from 2004 to 2016. Multinomial regression was used to compare utilization (single modality vs multimodal treatment with or without surgery vs no treatment) between EOPC and AOPC. Kaplan-Meier methods were used to estimate overall survival (OS).

RESULTS

Of 248,634 patients, 15,710 (6.3%) had EOPC. There were more male patients (56% vs 50%), non-White patients, and privately insured patients (61% vs 30%) with EOPC versus AOPC, without notable differences in clinical stage distribution. Patients with EOPC received more chemotherapy (38% vs 29%), surgery (9% vs 6.9%), chemoradiation (12% vs 9.2%), and multimodal treatment (21% vs 15%). The odds of receiving multimodal curative therapy were significantly higher for patients with EOPC versus patients with AOPC after adjustments for confounders (odds ratio, 3.89; 95% confidence interval [CI], 3.66-4.15; P < .001). Nineteen percent of patients with EOPC, in contrast to 39% of patients with AOPC, received no treatment. Patients with AOPC more frequently declined chemotherapy (15% vs 9.5%). One-year OS was higher for EOPC versus AOPC across each stage (0/I/II, 72% [95% CI, 71%-74%] vs 53% [95% CI, 53%-54%]; III, 48% [95% CI, 45%-50%] vs 38% [95% CI, 37%-38%]; IV, 25% [95% CI, 24%-26%] vs 15% [95% CI, 15%-15%]) and treated patients (0/I/II, 75% [95% CI, 74%-77%] vs 64% [95% CI, 63%-64%]; III, 51% [95% CI, 49%-54%] vs 47% [95% CI, 47%-48%]; IV, 29% [95% CI, 28%-31%] vs 23% [95% CI, 23%-24%]).

CONCLUSIONS

Patients with EOPC receive more oncologic therapy than patients with AOPC, although the intensity, type, and duration of chemotherapy are not available in the NCDB; however, 19% and 39%, respectively, receive no therapy. Underutilization may explain suboptimal oncologic outcomes. Efforts to improve access and treatment utilization in all age groups are warranted.

Association of Ablative Radiation Therapy With Survival Among Patients With Inoperable Pancreatic Cancer

Importance

Surgical resection has been considered the only curative option for patients with pancreatic cancer. Nonoperative local treatment options that can provide a similar benefit are needed. Emerging radiation techniques that address organ motion have enabled curative radiation doses to be given in patients with inoperable disease.

Objective

To determine the association of hypofractionated ablative radiation therapy (A-RT) with survival for patients with locally advanced pancreatic cancer (LAPC) treated with a novel radiation planning and delivery technique.

Design, Setting, and Participants

This cohort study included 119 consecutive patients treated with A-RT between June 2016 and February 2019 and enrolled in a prospectively maintained database. Patients were treated with a standardized technique within a large academic cancer center regional network. All patients with localized, unresectable, or medically inoperable pancreatic cancer with tumors of any size and less than 5 cm luminal abutment with the primary tumor were eligible.

Interventions

Ablative RT (98 Gy biologically effective dose) was delivered using standard equipment. Respiratory gating, soft tissue image guidance, and selective adaptive planning were used to address organ motion and limit the dose to surrounding luminal organs.

Main Outcomes and Measures

The primary outcome was overall survival (OS). Secondary outcomes included incidence of local progression and progression-free survival.

Results

Between 2016 and 2019, 119 patients (59 men, median age 67 years) received A-RT, including 99 with T3/T4 and 53 with node-positive disease, with a median carbohydrate antigen 19-9 (CA19-9) level greater than 167 U/mL. Most (116 [97.5%]) received induction chemotherapy for a median of 4 months (0.5-18.4). Median OS from diagnosis and A-RT were 26.8 and 18.4 months, respectively. Respective 12- and 24-month OS from A-RT were 74% (95% CI, 66%-83%) and 38% (95% CI, 27%-52%). Twelve- and 24-month cumulative incidence of locoregional failure were 17.6% (95% CI, 10.4%-24.9%) and 32.8% (95% CI, 21.6%-44.1%), respectively. Postinduction CA19-9 decline was associated with improved locoregional control and survival. Grade 3 upper gastrointestinal bleeding occurred in 10 patients (8%) with no grade 4 to 5 events.

Conclusions and Relevance

This cohort study of patients with inoperable LAPC found that A-RT following multiagent induction therapy for LAPC was associated with durable locoregional tumor control and favorable survival. Prospective randomized trials in patients with LAPC are warranted.

Leptomeningeal disease in pancreas ductal adenocarcinoma: A manifestation of longevity

BACKGROUND

/Objectives: Pancreatic adenocarcinoma (PDAC) metastatic to the leptomeninges is a rare and lethal event. Leptomeningeal disease (LMD) research is limited in PDAC, and insights into clinical descriptors, possible disease predictors, and treatment strategies is necessitated.

METHODS

Memorial Sloan Kettering databases were queried with Institutional Review Board approval to identify patients with LMD and PDAC treated between January 2000 and June 2020. Medical record review was used to abstract clinical, genomic, pathologic, and radiographic data. Overall survival was calculated from date of PDAC diagnosis to date of death. Previously published literature on LMD from PDAC was reviewed.

RESULTS

Four patients with LMD from PDAC were identified, two males and two females. Age at diagnosis ranged from 57 to 68 years. All four patients had predominant lung metastasis and a relatively low burden of intra-abdominal disease. Somatic testing indicated alterations typical of PDAC and no PDAC defining pathogenic germline mutations were identified. An extended clinical course prior to LMD diagnosis was observed in all patients, ranging from 16 to 148 months. Upon diagnosis of LMD, three patients elected for supportive care and one patient received a limited course of craniospinal radiation. The median survival following diagnosis of LMD was 1.6 months (range 0.5-2.8 months).

CONCLUSIONS

LMD from PDAC is a rare occurrence that may be more frequent in patients with lung metastasis and/or a more indolent clinical course. Following diagnosis of LMD, prognosis is poor, and survival is short. New treatment strategies for this manifestation of PDAC are needed.

Phase 1 cohort expansion study of LY3023414, a dual PI3K/mTOR inhibitor, in patients with advanced mesothelioma

BACKGROUND LY3023414 is a selective, ATP competitive inhibitor of class I PI3K isoforms, mTORC1/2 and DNA-PK. A Phase 1 dose escalation, 200 mg twice daily (BID) of LY3023414 was the determined recommended phase 2 dose (RP2D). We report the antitumor activity and safety of LY3023414 monotherapy in patients with advanced mesothelioma.METHODS Patients enrolled had advanced malignant pleural or peritoneal mesothelioma with measurable disease, ECOG PS 0–1, were refractory or ineligible to receive standard therapies. Patients received LY3023414 200 mg BID. This dose expansion cohort is intended to evaluate preliminary antitumor activity of LY3023414 by overall response rate. Safety, tolerability and pharmacokinetics were assessed. Biomarkers associated with treatment response was an exploratory endpoint. RESULTS Forty-two patients received LY3023414 for a median duration of 11.2 weeks (range: 1.1–53.0). One patient had a confirmed partial response (PR) (ORR 2.4%). Three patients had an unconfirmed PR. Seventeen patients had stable disease (SD) (DCR 43%). Most common adverse events (AEs) included fatigue (43%), nausea (43%), decreased appetite (38%), vomiting (33%), and diarrhea (29%). AEs were mostly mild or moderate. Grade ≥ 3 AEs were reported for 21% of patients with fatigue as the most frequent event (10%). Alterations of BAP1 were identified in 11/19 patients as the most common molecular aberration, followed by SETD2 and NF2 alterations. No obvious pattern of genetic changes/mutations in single genes or pathways was associated with anti-tumor activity. CONCLUSION LY3023414 monotherapy (200 mg BID) demonstrated an acceptable and manageable safety profile with limited single-agent activity in patients with advanced mesothelioma. ClinicalTrials.gov identifier: NCT01655225; Date of registration: 19 July 2012.

Phase II Single-arm Study of Durvalumab and Tremelimumab with Concurrent Radiotherapy in Patients with Mismatch Repair-proficient Metastatic Colorectal Cancer

PURPOSE

Immune checkpoint inhibition (ICI) alone is not active in mismatch repair-proficient (MMR-P) metastatic colorectal cancer (mCRC), nor does radiotherapy alone result in objective systemic benefit. However, combined radiotherapy plus ICI can induce systemic antitumor immunity in preclinical and clinical models.

PATIENTS AND METHODS

In this single-center, phase II study, patients with chemotherapy-refractory MMR-P mCRC received durvalumab 1,500 mg plus tremelimumab 75 mg every 4 weeks plus radiotherapy. The primary endpoint was objective response rate (ORR) in nonirradiated lesions. Treatment and efficacy were correlated with peripheral immune cell profiles.

RESULTS

We enrolled 24 patients, and report outcomes after a median follow-up of 21.8 (range: 15.9-26.3) months. The ORR was 8.3% (2 patients) [95% confidence interval (CI), 1.0-27.0]. The median progression-free survival was 1.8 (95% CI, 1.7-1.9) months, median overall survival was 11.4 (95% CI, 10.1-17.4) months. Twenty five percent of patients (n = 6) had treatment-related grade 3-4 adverse events. We observed increased circulating CD8⁺ T lymphocyte activation, differentiation, and proliferation in patients with objective response.

CONCLUSIONS

This combination of radiotherapy plus ICI study did not meet the prespecified endpoint criteria to be considered worthwhile for further study. However, rare instances of systemic immune augmentation and regression in nonirradiated lesions were observed (an abscopal response). Combination durvalumab and tremelimumab plus radiotherapy is feasible in MMR-P mCRC with a manageable safety profile. Further studies of novel immunotherapy combinations, and identification of biomarkers predictive of abscopal response are warranted.

Noninvasive Detection of Polyclonal Acquired Resistance to FGFR Inhibition in Patients With Cholangiocarcinoma Harboring FGFR2 Alterations

PURPOSE

Fibroblast growth factor receptor (FGFR) 2 alterations, present in 5%-15% of intrahepatic cholangiocarcinomas (IHC), are targets of FGFR-directed therapies. Acquired resistance is common among patients who respond. Biopsies at the time of acquired resistance to targeted agents may not always be feasible and may not capture the genetic heterogeneity that could exist within a patient. We studied circulating tumor DNA (ctDNA) as a less invasive means of potentially identifying genomic mechanisms of resistance to FGFR-targeted therapies.

MATERIALS AND METHODS

Serial blood samples were collected from eight patients with FGFR-altered cholangiocarcinoma for ctDNA isolation and next-generation sequencing (NGS) throughout treatment and at resistance to anti-FGFR-targeted therapy. ctDNA was sequenced using a custom ultra-deep coverage NGS panel, incorporating dual index primers and unique molecular barcodes to enable high-sensitivity mutation detection.

RESULTS

Thirty-one acquired mutations in FGFR2, 30/31 located in the kinase domain, were identified at resistance in six of eight patients with detectable ctDNA. Up to 13 independent FGFR2 mutations were detected per patient, indicative of striking genomic concordance among resistant subclones.

CONCLUSION

ctDNA could be an effective means to longitudinally monitor for acquired resistance in FGFR2-altered IHC. The numerous acquired genetic alterations in FGFR2 suggest frequent polyclonal mechanisms of resistance that cannot be detected from single-site tissue biopsies.

Pediatric nasal dermoid- a decade's experience from a South Indian tertiary care centre

INTRODUCTION

Nasal dermoid sinus cyst (NDSC) are uncommon congenital lesions in children.

OBJECTIVE

To review the clinical and radiological presentation and study the surgical outcomes of this uncommon lesion.

METHOD

Retrospective chart review of all children diagnosed with nasal dermoid from 2010 to 2020 at a tertiary referral hospital in South India was executed. The medical records were reviewed for demographics, lesion characteristics, imaging, operative details, and outcomes and literature review was performed.

RESULT

A total of 25 children [Mean age 3.7 yrs (Range 2-9 yrs)] with nasal dermoid sinus cysts were treated in the last decade. While 13 presented with a sinus, 11 presented with cyst and 1 had both. The lesions mainly involved the upper third of the nose in 10 children, middle one third in 6 and upper one third in 9 children. All underwent Magnetic Resonance Imaging, in 11 Computed Tomography also was done. A flow chart of the lesion characteristics and its management has been presented. Intraoperatively intracranial extension was present in four children. The approach to intracranial extension and corresponding literature review has been presented. Follow up ranged from one to six years. (Median 3.5 yrs) and no recurrence or complication was noted.

CONCLUSION

Nasal dermoid is an uncommon congenital anomaly. Preoperative evaluation must include imaging to assess extent and rule out intracranial extension. Surgical strategy depends on whether presentation is as sinus or cyst and location and extent of lesion. All surgical approaches have a good surgical and cosmetic outcome.

Genetic and clinical correlates of entosis in pancreatic ductal adenocarcinoma

Entosis is a type of regulated cell death that promotes cancer cell competition. Though several studies have revealed the molecular mechanisms that govern entosis, the clinical and genetic correlates of entosis in human tumors is less well understood. Here we reviewed entotic cell-in-cell (CIC) patterns in a large single institution sequencing cohort (MSK IMPACT clinical sequencing cohort) of more than 1600 human pancreatic ductal adenocarcinoma (PDAC) samples to identify the genetic and clinical correlates of this cellular feature. After case selection, 516 conventional PDACs and 21 ASCs entered this study and ~45,000 HPFs (median 80 HPFs per sample) were reviewed; 549 entotic-CICs were detected through our cohort. We observed that entotic-CIC occurred more frequently in liver metastasis compared with primary in PDAC. Moreover, poorly differentiated adenocarcinoma or adenosquamous carcinoma had more entotic-CIC than well or moderately differentiated adenocarcinoma. With respect to genetic features TP53 mutations, KRAS amplification, and MYC amplification were significantly associated with entosis in PDAC tissues. From a clinical standpoint entotic CICs were independently associated with a poor prognosis by multivariate Cox regression analysis when considering all cases or primary PDACs specifically. These results provide a contextual basis for understanding entosis in PDAC, a highly aggressive cancer for which molecular insights are needed to improve survival.

Genomic Methods Identify Homologous Recombination Deficiency in Pancreas Adenocarcinoma and Optimize Treatment Selection

PURPOSE

Genomic methods can identify homologous recombination deficiency (HRD). Rigorous evaluation of their outcome association to DNA damage response-targeted therapies like platinum in pancreatic ductal adenocarcinoma (PDAC) is essential in maximizing therapeutic outcome.

EXPERIMENTAL DESIGN

We evaluated progression-free survival (PFS) and overall survival (OS) of patients with advanced-stage PDAC, who had both germline- and somatic-targeted gene sequencing. Homologous recombination gene mutations (HRm) were evaluated: BRCA1, BRCA2, PALB2, ATM, BAP1, BARD1, BLM, BRIP1, CHEK2, FAM175A, FANCA, FANCC, NBN, RAD50, RAD51, RAD51C, and RTEL1 HRm status was grouped as: (i) germline versus somatic; (ii) core (BRCAs and PALB2) versus non-core (other HRm); and (iii) monoallelic versus biallelic. Genomic instability was compared using large-scale state transition, signature 3, and tumor mutation burden.

RESULTS

Among 262 patients, 50 (19%) had HRD (15% germline and 4% somatic). Both groups were analyzed together due to lack of difference in their genomic instability and outcome. Median [95% confidence interval (CI)] follow-up was 21.9 (1.4-57.0) months. Median OS and PFS were 15.5 (14.6-19) and 7 (6.1-8.1) months, respectively. Patients with HRD had improved PFS compared with no HRD when treated with first-line (1L) platinum [HR, 0.44 (95% CI: 0.29-0.67); P < 0.01], but not with 1L-non-platinum. Multivariate analysis showed HRD patients had improved OS regardless of their first-line treatment, but most had platinum exposure during their course. Biallelic HRm (11%) and core HRm (12%) had higher genomic instability, which translated to improved PFS on first-line platinum (1L-platinum) versus 1L-non-platinum.

CONCLUSIONS

Pathogenic HRm identifies HRD in patients with PDAC with the best outcome when treated with 1L-platinum. Biallelic HRm and core HRm further enriched benefit from 1L-platinum from HRD.

Alterations in driver genes are predictive of survival in patients with resected pancreatic ductal adenocarcinoma

BACKGROUND

KRAS, TP53, CDKN2A, and SMAD4 are established driver genes in pancreatic ductal adenocarcinoma (PDAC). This study was aimed at determining whether the mutational status of driver genes and those involved in DNA repair pathways are associated with clinical outcomes for individuals who undergo resection.

METHODS

Eligible individuals were those who underwent resection of PDAC and consented to targeted sequencing of their primary tumor via Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT). Genomic alterations were determined on the basis of MSK-IMPACT results from formalin-fixed, paraffin-embedded samples. Associations between genomic alterations and clinical outcomes were assessed.

RESULTS

Targeted sequencing was performed on 283 primary tumors resected between 2004 and 2017. The median follow-up was 23 months among survivors. Alterations in KRAS and TP53 were associated with worse overall survival (OS) in comparison to wild type (median for KRAS, 38.8 months [95% CI, 33.0-45.5 months] vs 91.0 months [95% CI, 34.8 months to not available (NA)]; P = .043; median for TP53, 37.4 months [95% CI, 32.1-42.8 months] vs 65.0 months [95% CI, 33.0 months to NA]; P = .035). KRAS G12D mutations were associated with worse OS (median, 31.6 months [95% CI, 25.3-45.5 months] vs 39.2 months [95% CI, 37.4-75.2 months]; P = .012). TP53 truncating mutations (median, 39.6 months [95% CI, 32.4-75.2 months] vs 33.9 months [95% CI, 24.0-39.0 months]; P = .020) and those associated with loss of heterozygosity (median, 26.6 months [95% CI, 21.6-44.2 months] vs 39.2 months [95% CI, 34.5-49.1 months]; P = .048) had decreased OS. TP53 alterations were independently associated with OS in a multivariate analysis (hazard ratio, 1.54; 95% CI, 1.01-2.33; P = .042). Individuals with germline alterations in homologous recombination deficiency (HRD) genes had improved OS in comparison with those without them (median, not reached vs 37.0 months; 95% CI, 33.0-49.8 months; P = .035).

CONCLUSIONS

In patients with resected PDAC, genomic alterations in KRAS and TP53 are associated with worse outcomes, whereas alterations in HRD genes are associated with a favorable prognosis. Further studies are needed to better define these alterations as biomarkers in resected PDAC.

A phase II study of siG12D-LODER in combination with chemotherapy in patients with locally advanced pancreatic cancer (PROTACT)

TPS4672

Background: KRAS alterations are the most frequent driver alterations identified in pancreas cancer; however, KRAS has remained an elusive therapeutic target. siG12D-LODER is a novel, miniature bio-degradable polymeric matrix encompassing a novel small interfering RNA targeting KRAS G12D and all additional G12X mutations (G12C, G12V...). The siG12D-LODER is inserted directly into the pancreas tumor via endoscopic intervention. A Phase 1/2a dose escalation and expansion study of patients receiving a one-time dose of siG12D-LODER with ongoing chemotherapy demonstrated that the combination was well-tolerated and safe and exhibited promising potential efficacy with 10/12 patients achieving disease control and median overall survival 15.1 months (Golan, Oncotarget 2015). Methods: This phase 2 study was initially designed as a randomized, two arm, open label study of gemcitabine and nab-paclitaxel with or without siG12D-LODER for patients with locally advanced pancreas cancer with planned 40 patients in each arm and primary endpoint of progression-free survival. Eighteen patients were enrolled in the chemotherapy alone arm and 18 in the chemotherapy and siG12D-LODER arm. After an interim analysis, the study design has been amended and is now a single arm study in which patients (N=39) with both borderline resectable and locally advanced pancreas cancer will receive investigator’s choice of chemotherapy (the combination of gemcitabine/nab-paclitaxel or modified FOLFIRINOX) and all patients will receive up to three doses of the siG12D-LODER administered once every 12 weeks. Primary endpoint is overall response rate after final siG12D-LODER insertion. Secondary endpoints include duration of response, progression-free survival, overall survival, time to response, percentage of patients proceeding to surgical resection, and percentage of patients receiving radiation therapy. Exploratory analyses include evaluation of KRAS mutation status and monitoring of circulating free DNA and circulating tumor cells. The amended protocol is now open for accrual and four patients having been enrolled to date. Trial accrual is anticipated to be completed by December 2020. Clinical trial information: NCT01676259 .

Mismatch Repair-Deficient Rectal Cancer and Resistance to Neoadjuvant Chemotherapy

PURPOSE

Evaluate response of mismatch repair-deficient (dMMR) rectal cancer to neoadjuvant chemotherapy.

EXPERIMENTAL DESIGN

dMMR rectal tumors at Memorial Sloan Kettering Cancer Center (New York, NY) were retrospectively reviewed for characteristics, treatment, and outcomes. Fifty patients with dMMR rectal cancer were identified by IHC and/or microsatellite instability analysis, with initial treatment response compared with a matched MMR-proficient (pMMR) rectal cancer cohort. Germline and somatic mutation analyses were evaluated. Patient-derived dMMR rectal tumoroids were assessed for chemotherapy sensitivity.

RESULTS

Of 21 patients receiving neoadjuvant chemotherapy (fluorouracil/oxaliplatin), six (29%) had progression of disease. In comparison, no progression was noted in 63 pMMR rectal tumors (P = 0.0001). Rectal cancer dMMR tumoroids reflected this resistance to chemotherapy. No genomic predictors of chemotherapy response were identified. Of 16 patients receiving chemoradiation, 13 (93%) experienced tumor downstaging; one patient had stable disease, comparable with 48 pMMR rectal cancers. Of 13 patients undergoing surgery, 12 (92%) had early-stage disease. Forty-two (84%) of the 50 patients tested positive for Lynch syndrome with enrichment of germline MSH2 and MSH6 mutations when compared with 193 patients with Lynch syndrome-associated colon cancer (MSH2, 57% vs 36%; MSH6, 17% vs 9%; P < 0.003).

CONCLUSIONS

Over one-fourth of dMMR rectal tumors treated with neoadjuvant chemotherapy exhibited disease progression. Conversely, dMMR rectal tumors were sensitive to chemoradiation. MMR status should be performed upfront in all locally advanced rectal tumors with careful monitoring for response on neoadjuvant chemotherapy and genetic testing for Lynch syndrome in patients with dMMR rectal cancer.

Young-onset pancreas cancer (PC) in patients less than or equal to 50 years old at Memorial Sloan Kettering (MSK): Descriptors, genomics, and outcomes

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Background: For individuals ≤ 50 years old, cancer incidence is increasing, particularly gastrointestinal and obesity related cancers (Sung, Lancet Public Health 2019). Limited details are known about young onset PC. Herein, we report the epidemiologic, pathologic, and molecular characteristics of PC in patients (pts) ≤ 50 years. Methods: MSK institutional database was queried for medical and treatment history, genomics, and outcomes in pts ≤ 50 years old diagnosed with PC between January 2008 and July 2018. Neuroendocrine cancers were excluded. Overall survival (OS) from date of PC diagnosis was estimated using Kaplan-Meier methods. Results: N = 450 pts ≤ 50 years old with a diagnosis of PC were identified. Ninety-six percent had adenocarcinoma, and 4% had acinar cell carcinoma/other histologies. Table summarizes demographics. Median OS was 16 months in the entire cohort and 11.3 months in stage IV disease. For N = 236 pts diagnosed after 2014, 119 (50%) underwent successful somatic testing with at least one alteration identified, and 21/119 tumors were RAS wild-type with identification of several actionable alterations (NRG1 fusions (n=2), NTRK fusions (n=2), IDH1 R132C (n=1), and microsatellite unstable tumors (n=1) ). N = 114 pts had germline testing (routine after 2015), and 33/114 (29%) had pathologic germline alterations, including BRCA1/2 (n=18), CHEK2 (n=3), PALB2 (n=3), ATM (n=2), MLH1 (n=1), and MSH3 (n=1). Conclusions: Pathogenic germline alterations are present in a substantial percentage of pts with young onset PC, and actionable somatic alterations were seen frequently in the subgroup of young onset PC RAS-wild type tumors. These observations underpin the need for germline and somatic profiling in PC. [Table: see text]

Pancreatic ductal adenocarcinoma (PDAC), BRCA: Detailed analysis and outcomes of cohort from Memorial Sloan Kettering Cancer Center (MSK)

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Background: Given encouraging responses of platinum agents and poly-ADP ribose polymerase inhibitors (PARPi) in BRCA mutated (mut) PDAC, we sought to identify patients (pts) with BRCA mut PDAC treated at MSKCC and to evaluate outcome. Methods: Institutional database at MSK with IRB approval was queried for PDAC germline (g) or somatic (s) BRCA1/2 mut. Genomic profiling, clinicopathologic characteristics and outcomes were collected. Overall survival (OS) from diagnosis was estimated using Kaplan-Meier method. Results: n = 126 with BRCA1/2 mut PDAC were identified between 1/2011-12/2018. n = 77 (61%) male and median age of 62 (range 24-85) at diagnosis. n = 78 (62%) had g BRCA mut (n = 21 BRCA1; n = 57 BRCA2). n = 54 (43%) had a family history of BRCA-related malignancies; 35pts (28%) with a personal history of other BRCA-associated malignancy. n = 66 (52%) AJCC stage IV; of these 43pts (65%) received platinum-based therapy with a partial response (PR) in 35pts (81%); median duration 7 months (m) (range 0.5-39m). n = 40 (32%) received ≥ 4 lines of therapy (range 1-6 lines). n = 44 (35%) received PARPi and 11% (n = 14) received immunotherapy. Median OS for the entire cohort 32.1 m (95% CI 23.9, 42.6). Median OS for stage I-II 49.9m (95% CI 38.5,-); stage III 43m (95% CI 33.9,-) and stage IV 19.1m (95% CI 19.1 16.1,25.8). We did not observe a statistically significant difference in OS between BRCA1 vs BRCA2 pts. Conclusions: BRCA mut PDAC constitutes a small but likely distinct biologic subgroup. Improved OS was notable relative to historical data, possibly due to the integration of platinum and PARPi therapy and possibly due to contribution from disease biology. [Table: see text]

Phase I Study of Trifluridine/Tipiracil Plus Irinotecan and Bevacizumab in Advanced Gastrointestinal Tumors

PURPOSE

This two-part phase Ib trial determined the maximum tolerated dose (MTD) of the combination of trifluridine/tipiracil (FTD/TPI) and irinotecan in patients with advanced gastrointestinal tumors, and evaluated the safety, pharmacokinetics, and antitumor activity of the FTD/TPI, irinotecan, and bevacizumab triplet combination in previously treated metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

Dose escalation (3+3 design) in advanced gastrointestinal tumors was followed by expansion in mCRC. During dose escalation, patients received FTD/TPI (20-35 mg/m² twice daily; days 1-5 of a 14-day cycle) and irinotecan (120-180 mg/m²; day 1). During expansion, the MTD of FTD/TPI and irinotecan plus bevacizumab (5 mg/kg; day 1) was administered.

RESULTS

Fifty patients (26 across six dose-escalation cohorts and 24 in the expansion phase) were enrolled. Two dose-limiting toxicities (fatigue and neutropenia) were observed in the dose-escalation phase, and MTD was defined as FTD/TPI 25 mg/m² twice daily plus irinotecan 180 mg/m². In the expansion phase, 83% (20/24) experienced any-cause grade ≥3 adverse events (AEs) with the triplet combination, most frequently neutropenia (42%), leukopenia (25%), and diarrhea (12%). AEs of any-cause led to dosing interruptions, modifications, and discontinuations in 29%, 17%, and 4% of patients, respectively. No treatment-related deaths occurred. Three patients (12%) experienced partial responses and 16 (67%) patients had stable disease lasting >4 months. The median progression-free survival was 7.9 months (95% confidence interval, 5.1-13.4 months).

CONCLUSIONS

Tolerability and activity observed in this phase I trial support further investigation of the FTD/TPI-irinotecan-bevacizumab combination in previously treated mCRC.

Assessment of Hepatic Arterial Infusion of Floxuridine in Combination With Systemic Gemcitabine and Oxaliplatin in Patients With Unresectable Intrahepatic Cholangiocarcinoma: A Phase 2 Clinical Trial

Importance

Unresectable intrahepatic cholangiocarcinoma (IHC) carries a poor prognosis, with a median overall survival (OS) of 11 months. Hepatic arterial infusion (HAI) of high-dose chemotherapy may have potential benefit in these patients.

Objective

To evaluate clinical outcomes when HAI chemotherapy is combined with systemic chemotherapy in patients with unresectable IHC.

Design, Setting, and Participants

A single-institution, phase 2 clinical trial including 38 patients was conducted with HAI floxuridine plus systemic gemcitabine and oxaliplatin in patients with unresectable IHC at Memorial Sloan Kettering Cancer Center between May 20, 2013, and June 27, 2019. A confirmatory phase 1/2 study using the same therapy was conducted during the same time period at Washington University in St Louis. Patients with histologically confirmed, unresectable IHC were eligible. Resectable metastatic disease to regional lymph nodes and prior systemic therapy were permitted. Patients with distant metastatic disease were excluded.

Interventions

Hepatic arterial infusion of floxuridine and systemic administration of gemcitabine and oxaliplatin.

Main Outcomes and Measures

The primary outcome was progression-free survival (PFS) of 80% at 6 months.

Results

For the phase 2 clinical trial at Memorial Sloan Kettering Cancer Center, 42 patients with unresectable IHC were included and, of these, 38 patients were treated (13 [34%] men; median [range] age at diagnosis, 64 [39-81] years). The median follow-up was 30.5 months. Twenty-two patients (58%) achieved a partial radiographic response, and 32 patients (84%) achieved disease control at 6 months. Four patients had sufficient response to undergo resection, and 1 patient had a complete pathologic response. The median PFS was 11.8 months (1-sided 90% CI, 11.1) with a 6-month PFS rate of 84.1% (90% CI, 74.8%-infinity), thereby meeting the primary end point (6-month PFS rate, 80%). The median OS was 25.0 months (95% CI, 20.6-not reached), and the 1-year OS rate was 89.5% (95% CI, 80.2%-99.8%). Patients with resectable regional lymph nodes (18 [47%]) showed no difference in OS compared with patients with node-negative disease (24-month OS: lymph node negative: 60%; 95% CI, 40%-91% vs lymph node positive: 50%; 95% CI, 30%-83%; P = .66). Four patients (11%) had grade 4 toxic effects requiring removal from the study (1 portal hypertension, 2 gastroduodenal artery aneurysms, 1 infection in the pump pocket). Subgroup analysis showed significant improvement in survival in patients with IDH1/2 mutated tumors (2-year OS, 90%; 95% CI, 73%-99%) vs wild-type (2-year OS, 33%; 95% CI, 18%-63%) (P = .01). In the Washington University in St Louis confirmatory cohort, 9 patients (90%) achieved disease control at 6 months; the most common grade 3 toxic effect was elevated results of liver function tests, and median PFS was 12.8 months (1-sided 90% CI, 6.4).

Conclusions and Relevance

Hepatic arterial infusion plus systemic chemotherapy appears to be highly active and tolerable in patients with unresectable IHC; further evaluation is warranted.

Development of Genome-Derived Tumor Type Prediction to Inform Clinical Cancer Care

IMPORTANCE

Diagnosing the site of origin for cancer is a pillar of disease classification that has directed clinical care for more than a century. Even in an era of precision oncologic practice, in which treatment is increasingly informed by the presence or absence of mutant genes responsible for cancer growth and progression, tumor origin remains a critical factor in tumor biologic characteristics and therapeutic sensitivity.

OBJECTIVE

To evaluate whether data derived from routine clinical DNA sequencing of tumors could complement conventional approaches to enable improved diagnostic accuracy.

DESIGN, SETTING, AND PARTICIPANTS

A machine learning approach was developed to predict tumor type from targeted panel DNA sequence data obtained at the point of care, incorporating both discrete molecular alterations and inferred features such as mutational signatures. This algorithm was trained on 7791 tumors representing 22 cancer types selected from a prospectively sequenced cohort of patients with advanced cancer.

RESULTS

The correct tumor type was predicted for 5748 of the 7791 patients (73.8%) in the training set as well as 8623 of 11 644 patients (74.1%) in an independent cohort. Predictions were assigned probabilities that reflected empirical accuracy, with 3388 cases (43.5%) representing high-confidence predictions (>95% probability). Informative molecular features and feature categories varied widely by tumor type. Genomic analysis of plasma cell-free DNA yielded accurate predictions in 45 of 60 cases (75.0%), suggesting that this approach may be applied in diverse clinical settings including as an adjunct to cancer screening. Likely tissues of origin were predicted from targeted tumor sequencing in 95 of 141 patients (67.4%) with cancers of unknown primary site. Applying this method prospectively to patients under active care enabled genome-directed reassessment of diagnosis in 2 patients initially presumed to have metastatic breast cancer, leading to the selection of more appropriate treatments, which elicited clinical responses.

CONCLUSIONS AND RELEVANCE

These results suggest that the application of artificial intelligence to predict tissue of origin in oncologic practice can act as a useful complement to conventional histologic review to provide integrated pathologic diagnoses, often with important therapeutic implications.

Abstract 1672: Clinical validation of a genomics-based classifier to predict tissue of origin from targeted tumor sequencing

Introduction

Various classes of genomic alterations can now be robustly detected from targeted Next Generation Sequencing (NGS)-based tumor profiling assays. Despite recent advances in genome-directed cancer therapies and lineage-agnostic basket clinical trials, tissue of origin remains a critical determinant of tumor biology and therapeutic sensitivity. Therefore, efficiently harnessing the mutational information to predict tissue of origin from NGS data can further aid diagnosis and treatment.

Methods

We have developed a novel random forest machine learning classifier that infers tissue of origin from the mutational features of each tumor NGS profile. We trained and validated the model using prospective sequencing data from &gt;30,000 patients profiled by MSK-IMPACT, a custom FDA-authorized clinical sequencing assay. An initial version of this classifier trained on a smaller cohort, presented previously, has been further optimized to incorporate additional tumor types, genomic features, mutational signatures, and accessibility features for clinicians. Altogether, the model evaluates a comprehensive range of mutational features to generate predictions. In addition, we developed a framework for the prospective clinical implementation of our method that allows for extension to the expanding MSK-IMPACT cohort and utilization at the point of care.

Results

Overall, we predicted the correct cancer type in 74% of cases, with nearly half of cases predicted with high confidence (&gt;95%). In order to make this tool accessible to pathologists for real-time diagnostic and treatment decisions, we also have implemented APIs that transmit our classifier predictions to the cBioPortal for Cancer Genomics and the MPath console from MSK Molecular Diagnostics Service. With the additional samples and genomic features, our model predictions have been improved and are considered during clinical review and sign-out. This practice has brought about critical diagnostic changes and orthogonal validation in several cases. In one case, a patient referred to MSK with a misdiagnosis of metastatic breast cancer to the bladder underwent MSK-IMPACT sequencing for her primary breast tumor and bladder lesion. The model predictions, confirmed by orthogonal testing, classified two lesions as independent primaries of breast and bladder origins, leading to significant changes in treatment regimens.

Conclusion

Our work delineates the framework of utilizing and optimizing machine learning models on NGS-based sequencing data to aid diagnosis and treatment. The same framework can be applied to cell-free DNA sequencing, which will capture tumor spatial heterogeneity and improve classifier performance. These results indicate that leveraging machine learning to

predict tissue of origin complements conventional histologic review to provide integrated diagnoses, often with critical therapeutic implications.

Citation Format: Youyun Zheng, Alexander V. Penson, Niedzica Camacho, Evan Biederstedt, Ahmet Zehir, Cyriac Kandoth, Aijazuddin Syed, Anna M. Varghese, Hikmat A. Al-Ahmadie, Nikolaus Schultz, Marc Ladanyi, David B. Solit, David S. Klimstra, David Hyman, Barry Taylor, Michael F. Berger. Clinical validation of a genomics-based classifier to predict tissue of origin from targeted tumor sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1672.

Influence of WNT and DNA damage response pathway alterations on outcomes in patients with unresectable metastatic colorectal cancer

3585

Background: We assembled a large series of consecutive patients with unresectable metastatic colorectal cancer (mCRC) to identify genomic biomarkers of response and survival. Methods: Patients with unresectable mCRC treated at Memorial Sloan Kettering with genomic tumor profiling between 2014 and 2017 were included. Patients who underwent upfront metastasectomy or received neoadjuvant/conversion chemotherapy were excluded. Clinical information was retrieved from electronic medical records, and we evaluated associations between genomic profiles with progression free survival (PFS) on first-line chemotherapy and overall survival (OS). Categorical data were analyzed by Fisher exact test and time-to-event data were analyzed by Cox proportional hazards models. Results: Of 1453 mCRCs profiled in this period, 471 patients met the study criteria. Median age was 59 years (range, 18 to 95), and 73% of patients were stage IV at diagnosis. Most tumors (91%) were microsatellite stable (MSS). The most frequent first-line regimen was FOLFOX +/- bevacizumab (66%). Among MSS patients treated with oxaliplatin-containing regimens (n = 305), 7% harbored alterations in genes associated with DNA damage response (DDR) (BRCA1, BRCA2, ATM, PALB2). DDR gene alterations were not associated with PFS (P = 0.94) nor were different quartiles of large-state transitions (P = 0.54). Genomic alterations that significantly varied by duration of response included BRAF (16%, 10%, and 5% for PFS < 6 months, 6-12 months, and > 12 months, respectively) and APC (62%, 74%, and 80% for PFS < 6 months, 6-12 months, and > 12 months, respectively). APC mutation, single or dual, was associated with significantly longer PFS (HR 0.67) and OS (HR 0.59) in multivariate analysis versus no WNT pathway alteration or alterations in other WNT pathway genes (RNF43, AXIN2, CTNNB1). Conclusions: In unresectable mCRC patients, mutations in APC were associated with better outcomes; absence of an APC alteration or the occurrence of other WNT pathway alterations was associated with shorter survival. Somatic alterations in DDR genes were not associated with outcomes in mCRC patients receiving oxaliplatin-containing regimen.

A phase Ib dose-escalation and cohort-expansion study of safety and activity of the transforming growth factor (TGF) β receptor I kinase inhibitor galunisertib plus the anti-PD-L1 antibody durvalumab in metastatic pancreatic cancer

4124

Background: Pancreatic cancer (PC) is characterized by a highly immunosuppressive microenvironment, and immune checkpoint inhibitors as monotherapy have been ineffective to date. TGFβ is commonly viewed as a powerful immunosuppressive cytokine, and inhibition of its signaling reverses this suppression and activates adaptive immune responses. A combination of TGFβ and PD-L1 inhibition may act synergistically to induce immune restoration and to improve antitumor responses. This Phase 1b study (NCT02734160) evaluated the combination of galunisertib plus durvalumab in recurrent or refractory metastatic PC. Methods: Eligible patients (pts) were ≥18 years old, had ECOG status ≤1, and had not received treatment with anti-PD-1, anti-PD-L1, or TGFβ R1 kinase inhibitors. The primary objective was to assess the safety and the recommended dose of galunisertib given 14 days on/14 days off in combination with durvalumab 1500 mg every 4 weeks. Four dose levels of galunisertib were tested in the dose escalation portion of the study: 50 mg QD, 50 mg BID, 80 mg BID and 150 mg BID, followed by the cohort expansion portion of the study at the recommended Phase 2 dose (RP2D). Secondary objectives included preliminary assessment of activity by response rate, (RECIST v1.1), median PFS (mPFS), and OS (mOS). Results: 42 pts (25F/17M) were treated in the study (median age 56.5 y; 71.4% had received ≥2 prior systemic regimens). There was no dose limiting toxicity and galunisertib 150 mg BID was chosen as the RP2D. In the 32 pts treated at this dose, Grade ≥3 related AEs included AST and GGT elevations (2 pts each), and ALT and alkaline phosphatase elevations, and neutropenia (1 pt each). One partial response and 7/32 stable diseases were observed (disease control rate 25%); mPFS was 1.9 months (95% CI: 1.5, 2.2) and mOS was NR (95% CI: 3.6, NR). Biomarker data will be presented at the meeting. Conclusions: The combination of galunisertib plus durvalumab had an acceptable tolerability and safety profile. The activity of this combination in second and third line PC patients warrants further consideration. Clinical trial information: NCT02734160.

Non-invasive detection of acquired resistance to FGFR inhibition in patients with cholangiocarcinoma harboring FGFR2 alterations

4096

Background: FGFR2 alterations are present in 14% of cholangiocarcinomas (CCA) and are promising targets of investigational FGFR-directed therapies. Cell-free DNA profiling has emerged as a non-invasive approach to monitor disease and longitudinally characterize tumor evolution. We describe the use of circulating tumor DNA (ctDNA) among patients (pts) with FGFR2-altered CCA receiving FGFR-targeted therapy in the identification of acquired FGFR2 mutations (mut) at resistance. Methods: Serial blood samples were collected from 8 pts with FGFR-altered CCA for ctDNA isolation and next generation sequencing. Plasma ctDNA collected at baseline and resistance to FGFR-targeted therapy were sequenced using a custom ultra-deep coverage cfDNA panel, MSK-ACCESS, incorporating dual index primers and unique molecular barcodes to enable background error suppression and high-sensitivity mut detection. The assay was enhanced to include all protein-coding exons and relevant introns of FGFR2. In 5/8 pts, genomic profiling of an initial tumor biopsy was performed. Results: 8 pts with FGFR2-altered CCA (7 gene fusions, 1 amplification) were treated with FGFR-targeted therapies. 7/8 pts exhibited stable disease or partial response. 19 total acquired mut in FGFR2 were detected at resistance in 5/8 pts (between 1-9 unique mut identified in each sample). All mut were located in the kinase domain. Conclusions: Acquired mut in FGFR2 are seen in pts who have developed resistance to targeted therapy. CtDNA can be used to identify these mut at the time of acquired resistance. The multitude of FGFR2 mut observed within individual pts suggest heterogeneity and evolutionary convergence of resistance mechanisms. Our results illustrate the utility of ctDNA as a less invasive way to monitor for signs of resistance and to identify other potential targetable alterations. [Table: see text]

Homologous recombination deficiency (HRD): A biomarker for first-line (1L) platinum in advanced pancreatic ductal adenocarcinoma (PDAC)

4132

Background: HRD is an emerging biomarker for platinum therapy in PDAC. The clinical implications regarding differences in outcome between germline and somatic HRD in advanced PDAC treated with 1L platinum is unexplored. Methods: We evaluated overall survival (OS) for advanced PDAC (stage III/IV) based on their pathogenic germline (gHRD) and somatic HRD (sHRD) using integrated genomic profiling from MSK-IMPACT and 1L platinum use. HRD defined by pathogenic alterations from the following genes: BRCA1/2, PALB2, ARID1A/B/2, ATR, ATRX, ATM, BAP1, RAD50/51C/D, BRIP1, NBN, CHECK1/2, FANCA/C, CDK12, and MRE11. Results: Advanced PDAC patients (n=461) treated at MSK enrolled in a prospective database, were evaluated. Median follow-up was 27.6 months (95% CI, 24.6-30.6). Both germline and somatic profilings were available for n=350 (76%) but only somatic profiling was available for n=111 (24%). We identified n=52 patients with gHRD (11.3%), n=42 patients with sHRD (9.1%), and 48 patients with somatic VUS for HRD genes. From all 461 patients, the OS was not different between 1L non-platinum vs. 1L platinum groups (19 M vs. 19.3 M), regardleess of their HRD status. (Table) The OS was superior for gHRD vs. non-gHRD (28.7 M vs. 18.2 M), regardless of 1L treatment choice. However, similar significant OS superiority was neither observed in sHRD vs. non-sHRD, nor in VUS sHRD vs. non-VUS sHRD. In a subgroup analysis of 1L platinum treated patients, the OS was superior in gHRD vs. non-gHRD (NR vs. 17.9 M); however, there was no OS difference between sHRD and non-sHRD. Conclusions: In advanced PDAC patients, only gHRD predicted better overall survival for first-line platinum chemotherapy. These findings emphasize the importance of germline mutation testing of HRD in PDAC. Biomarker validation and functional definition of HRD such as loss of heterozygosity analysis is underway. [Table: see text]

Genomic profiling in pancreatic ductal adenocarcinoma and a pathway towards therapy individualization: A scoping review

CONTEXT

Pancreatic cancer (PDAC) is one of the most challenging cancers to treat with modest recent improvements in survival from new systemic therapies. There is growing interest in individualized therapy underpinned by somatic and germline genomic alterations.

OBJECTIVE

A systematic review of data on therapies targeting somatic and germline alterations, and their downstream pathways in PDAC.

METHOD

A systematic literature search was conducted using PRISMA guidelines to include relevant results published after January 1, 2008.

RESULTS

A total of 71 relevant studies were included. We identified 36 studies targeting the KRAS-pathway, the most common being with MEK-inhibitor therapy. Twenty-two studies were identified that evaluated platinum-based chemotherapy and PARP inhibitors in patients with deleterious mutations in DNA damage repair genes and have shown encouraging results. Immunotherapy has demonstrated activity in patients with mismatch repair deficiency/microsatellite instability.

CONCLUSION

Evidence from translational and clinical research presents an exciting platform for genomic targeted therapy in PDAC. Validity for targeting BRCA with platinum and PARP inhibitors and microsatellite instability with immune therapy has been established, nonetheless, evidence for targeting the common driver oncogenes is lacking and much work is needed. Of importance is identifying the subgroup of KRAS -wild type PDAC (approximately 5%) where there is enrichment for targetable opportunities.

Pilot study of plasma KRAS as a prognostic biomarker in localized pancreas ductal adenocarcinoma (PDAC)

294

Background: Validated predictive and prognostic biomarkers are needed in PDAC. Such biomarkers could predict response and resistance early in treatment. As 95% of PDAC harbor KRAS mutations (mKRAS), plasma mKRAS has utility as a biomarker. We explored the prognostic value of mKRAS in a PDAC cohort at Memorial Sloan Kettering. Methods: 10 mL of whole blood was collected at diagnosis of localized PDAC and early interval CT scan (approx. 8 weeks). DNA was extracted with QIAamp DNA kits (Qiagen, Valencia, CA). Single locus, if tissue KRAS known, or multiplex (G12A, G12C, G12D, G12R, G12S, G12V, G13D) digital droplet PCR (ddPCR) was performed with QX200 (BioRad, Hercules, CA) ddPCR system. Disease status was determined by radiographic, CA19-9 and clinical evaluation. Results: N = 18 enrolled (median age: 65 [range 34-85]). Median time between baseline (B) and interval (I) blood was 2.53 months (range 0.9-6). One had locally recurrent disease, 2 AJCC stage IIa, 1 IIb and 14 III. Three had tissue KRAS G12D mutation, 6 G12V and 9 unknown. Eight had gemcitabine-based treatment, 10 5-FU-based and 5 radiation. See table. mKRAS and CA19-9 at B were not associated with progression free survival (PFS) or overall survival (OS). mKRAS detection at I was associated with shorter PFS/OS (P < 0.01), but CA19-9 was not. mKRAS change from B to I was also associated with PFS/OS. For every 1 copy/mL increase in the change of mKRAS from B to I, the risk of death or progression/death increased by nearly 2 fold after controlling for baseline value (p = 0.01 for OS, p = 0.03 for PFS). Four patients, all undetectable mKRAS at I, went to surgery; 2/4 resected. Conclusions: In this pilot, 59% of localized PDAC patients had detectable mKRAS at B. mKRAS detection at I and change from B to I were associated with PFS/OS supporting that mKRAS early in treatment may be a useful prognostic and predictive marker in localized PDAC. We have initiated a large prospective trial to evaluate the predictive and prognostic potential of plasma mKRAS in advanced PDAC. [Table: see text]

A retrospective study of hepatic arterial infusion (HAI) FUDR/Dex and mitomycin C (MMC) for chemotherapy refractory unresectable intrahepatic cholangiocarcinomas (ICC)

432

Background: ICC are aggressive tumors with approximately 6,000 cases a year in US. The 5-year survival rate is less than 30% even for localized disease. There is only one approved line of systemic (SYS) treatment and further treatment options are necessary. HAI chemotherapy is an option to treat liver predominant cancers. Methods: After obtaining IRB approval, we retrospectively reviewed patients (pts) with ICC chemo refractory unresectable liver limited (LL) or liver dominant (LD) disease who received intrahepatic chemotherapy with HAI MMC. Baseline characteristics, previous lines of therapy, toxicity profile, combinations and radiographic responses were reviewed. Tumor genomic analyses were performed on samples using an on-site next generation sequencing (NGS) assay. Results: Between January 2011 and October 2018, 19 patients ICC with LL or LD disease were treated with HAI FUDR/Dex/MMC at Memorial Sloan Kettering Cancer Center. Disease was confined to the liver in 58% of the pts. All pts had previous chemotherapy (1-4 lines) and 14 (74%) previously had HAI FUDR/Dex. Of the 19 pts, 56% had HAI with FUDR/Dex and MMC, 43% had FUDR/Dex, MCC and SYS and 5% had HAI MMC and SYS. Seventeen patients were evaluable for response, two are being treated and will have response assessment for the meeting. Response was noted in 4 (23.5%), stable disease in 6 (35.5%) and progressive disease in 7 (41%) pts. Median overall survival from treatment was 6.1months (0.36-26). Median progression free survival was 3.65 months (0.36-9.53). Four patients had dose reductions. Common toxicity attributed to MMC was grade (G) one fatigue (32%), thrombocytopenia G1(16%) and G2 (5%). Of the 12 tumors analyzed to date the most 92% of tumors harbored at least one (0-10) genomic alteration. Common genomic alterations were ARID1 (25%), RASA1 (25%), IDH1(16.6%), NTRK (16.6%), TERT (16.6%), NRAS (16.6%), CDKN2 (16. 6%). FGFR2-FOXP1 and GTL2MEt fusions were found in one patient each. Conclusions: HAI FUDR/Dex/MMC containing regimens are active in pts with heavily pretreated refractory unresectable ICC. This strategy should be further investigated. Translational data will be presented.

Microsatellite Instability Is Associated With the Presence of Lynch Syndrome Pan-Cancer

PURPOSE

Microsatellite instability (MSI) and/or mismatch repair deficiency (MMR-D) testing has traditionally been performed in patients with colorectal (CRC) and endometrial cancer (EC) to screen for Lynch syndrome (LS)-associated cancer predisposition. The recent success of immunotherapy in high-frequency MSI (MSI-H) and/or MMR-D tumors now supports testing for MSI in all advanced solid tumors. The extent to which LS accounts for MSI-H across heterogeneous tumor types is unknown. Here, we establish the prevalence of LS across solid tumors according to MSI status.

METHODS

MSI status was determined using targeted next-generation sequencing, with tumors classified as MSI-H, MSI-indeterminate, or microsatellite-stable. Matched germline DNA was analyzed for mutations in LS-associated mismatch repair genes ( MLH1, MSH2, MSH6, PMS2, EPCAM). In patients with LS with MSI-H/I tumors, immunohistochemical staining for MMR-D was assessed.

RESULTS

Among 15,045 unique patients (more than 50 cancer types), LS was identified in 16.3% (53 of 326), 1.9% (13 of 699), and 0.3% (37 of 14,020) of patients with MSI-H, MSI-indeterminate, and microsatellite-stable tumors, respectively ( P < .001). Among patients with LS with MSI-H/I tumors, 50% (33 of 66) had tumors other than CRC/EC, including urothelial, prostate, pancreas, adrenocortical, small bowel, sarcoma, mesothelioma, melanoma, gastric, and germ cell tumors. In these patients with non-CRC/EC tumors, 45% (15 of 33) did not meet LS genetic testing criteria on the basis of personal/family history. Immunohistochemical staining of LS-positive MSI-H/I tumors demonstrated MMR-D in 98.2% (56 of 57) of available cases.

CONCLUSION

MSI-H/MMR-D is predictive of LS across a much broader tumor spectrum than currently appreciated. Given implications for cancer surveillance and prevention measures in affected families, these data support germline genetic assessment for LS for patients with an MSI-H/MMR-D tumor, regardless of cancer type or family cancer history.

Prospective Evaluation of Germline Alterations in Patients With Exocrine Pancreatic Neoplasms

Background

Identification of pathogenic germline alterations (PGAs) has important clinical and therapeutic implications in pancreas cancer. We performed comprehensive germline testing (GT) in an unselected prospective cohort of patients with exocrine pancreatic neoplasms with genotype and phenotype association to facilitate identification of prognostic and/or predictive biomarkers and examine potential therapeutic implications.

Methods

Six hundred fifteen unselected patients with exocrine pancreatic neoplasms were prospectively consented for somatic tumor and matched sample profiling for 410-468 genes. GT for PGAs in 76 genes associated with cancer susceptibility was performed in an "identified" manner in 356 (57.9%) patients and in an "anonymized" manner in 259 (42.1%) patients, using an institutional review board-approved protocol. Detailed clinical and pathological features, response to platinum, and overall survival (OS) were collected for the identified cohort. OS was analyzed with Kaplan-Meier curves.

Results

PGAs were present in 122 (19.8%) of 615 patients involving 24 different genes, including BRCA1/2, ATM, PALB2, and multiple additional genes associated with the DNA damage response pathway. Of 122 patients with germline alterations, 41.8% did not meet current guidelines for GT. The difference in median OS was not statistically significant between patients with and without PGA (50.8 months, 95% confidence interval = 34.5 to not reached, two-sided P = .94). Loss of heterozygosity was found in 60.0% of BRCA1/2.

Conclusions

PGAs frequently occur in pancreas exocrine neoplasms and involve multiple genes beyond those previously associated with hereditary pancreatic cancer. These PGAs are therapeutically actionable in about 5% to 10% of patients. These data support routinely offering GT in all pancreatic ductal adenocarcimona patients with a broad panel of known hereditary cancer predisposition genes.

Abstract CT062: A phase I dose escalation study of trifluridine and tipiracil (FTD/TPI) in combination with irinotecan (IRI) in patients with advanced gastrointestinal (GI) tumors

Background: FTD/TPI combines a thymidine-based nucleoside analog, FTD, and a thymidine phosphorylase inhibitor, TPI, and is approved for previously treated patients with metastatic colorectal cancer (mCRC). Preclinical results with FTD/TPI indicated additive antitumor activity with IRI. The primary objectives of this Phase I study were to determine the safety, maximum tolerated dose (MTD), and dose-limiting toxicity (DLT) of combined FTD/TPI and IRI treatment in patients with advanced GI tumors.

Methods: Patients aged ≥18 years with advanced GI tumors who were refractory to ≥1 line of chemotherapy were included. Patients were excluded if they had received any prior IRI dose reductions, dose delay, or growth factor support in the first 8 weeks of treatment with IRI. Escalating doses of FTD/TPI (20, 25, 30, or 35 mg/m2/dose BID p.o.) and IRI (30-minute i.v. infusion of 120, 150, or 180 mg/m2/dose) were administered using a standard 3+3 design. FTD/TPI was given on days 1-5 of 14-day cycles; IRI on day 1 of each cycle. DLT was assessed during the first 28 days.

Results: 26 patients were enrolled and assigned to 6 treatment cohorts consisting of 3-6 patients per cohort. The most common cancer types were colon (54%) and rectal (27%). All patients initiated treatment but 3 patients were not evaluable for DLT (2 patients had disease-related complications and 1 was ineligible). The majority (65%) of patients had received ≥4 lines of prior systemic therapies and 25/26 patients initiated cycle 3. Two patients in the dose-escalation phase were IRI-naïve. Mean relative dose intensities (ratio to planned) for FTD/TPI and IRI during the first 2 cycles were 92% and 93%, respectively. Two DLTs (grade 3 fatigue and grade 2 neutropenia resulting in a &gt;2-week delay to cycle 3) were observed in the FTD/TPI 30 mg/m2 and IRI 180 mg/m2 cohort. Thus, the MTD was FTD/TPI 25 mg/m2 and IRI 180 mg/m2. Based on a data cut-off point for the dose-escalation phase (March 22, 2016), grade ≥3 adverse events were reported in 15 patients (58%); the most common were fatigue (15%), nausea (11%), and vomiting (11%). Of 25 patients (data missing for 1 patient due to early discontinuation), the most common laboratory abnormalities that worsened from baseline were leukocytes (28%), neutrophils (24%), lymphocytes (20%), hemoglobin (16%), and hypokalemia (12%).

Conclusions: In patients with advanced GI tumors, the safety findings of FTD/TPI in combination with IRI were consistent with the existing safety profiles of these drugs. The MTD was declared as FTD/TPI 25 mg/m2 and IRI 180 mg/m2. Further safety, pharmacokinetic, and efficacy (with bevacizumab) analyses in patients with mCRC are complete and will be presented at a later date.

Citation Format: Anna M. Varghese, Dana B. Cardin, Jon Hersch, Al B. Benson, Howard S. Hochster, Robert Winkler, Fabio Benedetti, Kensuke Hamada, Jordan D. Berlin, Leonard Saltz. A phase I dose escalation study of trifluridine and tipiracil (FTD/TPI) in combination with irinotecan (IRI) in patients with advanced gastrointestinal (GI) tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT062.

Nanoliposomal irinotecan with fluorouracil for the treatment of advanced pancreatic cancer, a single institution experience

Background

Effective treatment options for advanced pancreatic cancer are finite. NAPOLI-1, a phase III randomized trial, demonstrated the efficacy of nanoliposomal irinotecan with fluorouracil/leucovorin (nal-IRI + 5-FU/LV) for the treatment of advanced pancreatic cancer following progression on gemcitabine-based chemotherapy. There are limited additional data on the safety and efficacy of nal-IRI + 5-FU/LV following FDA approval in October 2015. We examined the post-approval safety and effectiveness of nal-IRI + 5-FU/LV in advanced pancreatic cancer patients receiving treatment at Memorial Sloan Kettering Cancer Center.

Methods

A retrospective chart review was conducted of all patients beginning treatment with nal-IRI + 5-FU/LV from October 2015 through June 2017. Using the electronic medical record and institutional database, information was extracted pertaining to demographics, performance status (ECOG), prior therapies, dose, duration of treatment, adverse events, progression free survival (PFS), overall survival (OS) and treatment response.

Results

Fifty six patients were identified. Median progression free survival (PFS) was 2.9 months and median overall survival (OS) was 5.3 months. Patients with prior disease progression on irinotecan experienced PFS and OS of 2.2 and 3.9 mo, respectively. Patients without prior irinotecan exposure experienced significantly longer PFS (4.8 mo, p = 0.02) and OS (7.7 mo, p = 0.002), as did patients who received prior irinotecan without disease progression (PFS, 5.7 mo, p = 0.04; OS, 9.0 mo, p = .04). Progression on prior irinotecan was associated with greater lines of prior advanced disease chemotherapy (2 vs 1). Dose reductions (DR) were most frequently due to fatigue (42%) and diarrhea (37%), but were not associated with worse outcomes. In fact, patients with ≥1 DR experienced longer PFS (5.4 v 2.6 mo, p = 0.035). Sequential therapy with nab-paclitaxel + gemcitabine (nab-P + Gem) followed by nal-IRI + 5-FU/LV (n = 25) resulted in OS of 23.0 mo. Mutations in TP53 were associated with shorter PFS.

Conclusions

These data support the safety and efficacy of nal-IRI + 5-FU/LV, reinforcing results of NAPOLI-1. Patients without disease progression on prior irinotecan fared significantly better than patients with progression, when treated with nal-IRI + 5-FU/LV. Sequential therapy with nab-P + Gem followed by nal-IRI + 5-FU/LV demonstrates encouraging median OS. These findings provide guidance for patients most likely to benefit from nal-IRI + 5-FU/LV.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4605-1) contains supplementary material, which is available to authorized users.

Pan-cancer microsatellite instability to predict for presence of Lynch syndrome

LBA1509

Background: The success of immunotherapy in microsatellite unstable (MSI-H) and/or DNA mismatch repair deficient (MMR-D) tumors has resulted in routine MSI-H/MMR-D testing in advanced solid tumors. Unlike colorectal (CRC) and endometrial cancer (EC), where this has long been undertaken, the characterization of Lynch syndrome (LS) across heterogeneous MSI-H/MMR-D tumors is unknown. Methods: Through a targeted NGS panel, MSI status was determined via MSIsensor. Scores of < 3, ≥3 to < 10, or ≥10 designated Microsatellite stable (MSS), MSI-Indeterminate (MSI-I) or MSI-H status, respectively. Germline mutations were assessed in MLH1, MSH2, MSH6, PMS2, EPCAM. Immunohistochemical staining (IHC) for MMR-D and tumor signatures in LS patients were assessed. Clinical variables were correlated with MSI and compared via Chi square or T-test. Results: Of 15,045 tumors spanning > 50 cancers , 93.2% were MSS, 4.6% MSI-I, and 2.2% MSI-H. Germline mutations were identified in 0.3% (37/14,020), 1.9% (13/699), and 16.3% (53/326) in the MSS, MSI-I, and MSI-H groups, respectively (p-value < 0.001). 25% of 1,025 MSI-H/MSI-I tumors were CRC/EC, but 50% (33/66) of LS patients had MSI-H/MSI-I tumors less commonly or not previously associated with LS (mesothelioma, sarcoma, adrenocortical, melanoma, ovarian germ cell). LS pts with MSI-H/MSI-I non-CRC/EC tumors only met testing criteria in 63.6% of cases, had lower MSIsensor scores, and were more likely to be MSI-I (MSI-I: non-CRC/EC, 30.3% (10/33) vs CRC/EC 9.1% (3/33); p-value = 0.03). IHC was completed in 86.4% (57/66) of LS MSI-H/MSI-I tumors, with 98.3% MMR-D-concordance. Of LS pts with MSS tumors, 78% had MSH6/PMS2 mutations, but 71% of LS pts with MSI-H/MSI-I tumors had MLH1/MSH2/EPCAM mutations(p-value < 0.001). 89% (33/37) of MSS tumors of LS pts had non-MMR-D signatures. Conclusions: MSI-H/MMR-D is predictive of LS across tumor types and suggests a more heterogeneous spectrum of LS-associated cancers than previously appreciated. Nearly 40% of LS pts with MSI-H/MMR-D non-CRC/EC tumors did not meet clinical criteria for genetic testing, suggesting that MSI-H/MMR-D tumors, regardless of cancer type or family history, should prompt germline testing for the evaluation of LS.