Primary Tumor Location and Outcomes After Cytoreductive Surgery and Intraperitoneal Chemotherapy for Peritoneal Metastases of Colorectal Origin

BACKGROUND

The aim of this study is to evaluate outcomes in patients with peritoneal metastasis of colorectal cancer (pmCRC) who underwent cytoreductive surgery and intraperitoneal chemotherapy (CRS/IPC) in relation to the location of the primary tumor. Regional therapy, including cytoreductive surgery and intraperitoneal chemotherapy, has been associated with improved survival in patients with pmCRC. Location of the primary tumor has been shown to be prognostic in patients with metastasis.

PATIENTS AND METHODS

A retrospective review was performed for all patients who underwent complete cytoreduction and intraperitoneal chemotherapy from 2010 to 2017, examining patient and tumor characteristics, overall and recurrence-free survival, recurrence patterns, and tumor mutational profiles.

RESULTS

Ninety-three patients were included in the study: 49 (53%) with a right-sided and 44 (47%) with a left-sided primary tumor. Patients with a right-sided tumor had significantly shorter recurrence-free survival (median, 6.3 months; 95% CI, 4.7-8.1 months vs 12.3 months; 95% CI, 3.6-21.7 months; P = 0.02) and overall survival (median, 36.6 months; 95% CI, 26.4-46.9 months vs 83.3 months; 95% CI 44.2-122.4 months; P = 0.03). BRAF and KRAS mutations were more frequent in right-sided tumors, and APC and TP53 mutations were more frequent in left-sided tumors, which were more chromosomally instable. BRAF mutations were associated with early recurrence.

CONCLUSIONS

Tumor sidedness is a predictor of oncological outcomes after CRS/IPC. Tumor sidedness and molecular characteristics should be considered when counseling patients regarding expected outcomes and when selecting or stratifying pmCRC patients for clinical trials of regional therapy.

Abstract 1122: Germline mutation prevalence in young adults with cancer

The identification of germline pathogenic variants in young adult cancer patients is especially critical given risk of second primary cancers, need for appropriate long-term surveillance, potential reproductive implications, and cascade testing of at-risk family members. We sought to determine the prevalence of germline susceptibility in cancer patients, age 18-39, across diverse solid tumor phenotypes. A total of 1201 cases, diagnosed between ages 18-39 were prospectively ascertained from 2015-2019 under a human subjects-approved protocol that provided result transmission of germline analysis. A next-generation sequencing panel consisting of up to 88 genes previously implicated in cancer predisposition (MSK-IMPACT) was utilized. Based on SEER data, we refined our population of young cancer patients into those with 1) early-onset cancer (EO-CA), defined as cancer wherein age 39 is >1 standard deviation (STD) below the mean age of diagnosis for that cancer type and 2) young-adult cancer (YA-CA), defined as cancer wherein age 39 is <1 STD below the mean age at cancer diagnosis. Among EO-CA (n=877) cases, the most common cancers included colorectal, breast, kidney, pancreas, and ovarian cancer, while among YA-CAs (n=324), the most frequent diagnoses were sarcoma, brain, testicular and thyroid cancer. Germline prevalence of likely pathogenic or pathogenic variants (PV) was 21% in the EO-CA versus 13% in YA-CA patients (p=0.002), with an enrichment of high- and moderate-penetrance PVs in the EO-CA cohort (15% vs 10%; p=0.01). Among EO-CAs, the most commonly mutated genes were BRCA2, BRCA1, CHEK2 and ATM, with pancreas, breast, and kidney cancer harboring the highest rates of germline PVs. In contrast, in the YA-CA cohort, TP53 and SDHA mutations predominated. Among YA-CA patients with sarcoma, the 18.1% mutation prevalence was similar to the prevalence in EO-CAs. Matched tumor analyses assessing biallelic inactivation is on-going and will be presented. Among young adults with early-onset phenotypes of malignancies typically presenting at later ages, the increased prevalence of germline PVs supports a role for genetic testing irrespective of tumor type.

Citation Format: Zsofia K. Stadler, Anna Maio, Angelika Padunan, Yelena Kemel, Erin Salo-Mullen, Margaret Sheehan, Kimeisha Belanfanti, Prince R. Tejada, Ozge Birsoy, Diana Mandelker, Liying Zhang, Jesse Galle, Darren Feldman, Laura Boucai, Julia Glade Bender, Anna Piotrowski, Carol Aghajanian, Karen A. Cadoo, Maria I. Carlo, Michael Walsh, Yelena Janjigian, Eileen O'Reilly, Lisa M. DeAngelis, David B. Solit, Barry Taylor, Andrea Cercek, William Tap, Mark E. Robson, Michael F. Berger, Kenneth Offit, Luis A. Diaz. Germline mutation prevalence in young adults with cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1122.

Adjuvant Hepatic Artery Infusion Chemotherapy is Associated With Improved Survival Regardless of KRAS Mutation Status in Patients With Resected Colorectal Liver Metastases: A Retrospective Analysis of 674 Patients

OBJECTIVE

To investigate the impact of adjuvant hepatic artery infusion (HAI) in relation to KRAS mutational status in patients with resected colorectal cancer liver metastases (CRLM).

BACKGROUND

Patients with KRAS-mutated CRLM have worse outcomes after resection. Adjuvant HAI chemotherapy improves overall survival after liver resection.

METHODS

Patients with resected CRLM treated at MSKCC with and without adjuvant HAI who had available KRAS status (wild-type, WT; mutated, MUT) were reviewed from a prospectively maintained institutional database. Correlations between KRAS status, adjuvant HAI, clinical factors, and outcomes were analyzed. Cox proportional hazard model was used to adjust for confounders.

RESULTS

Between 1993 and 2012, 674 patients (418 KRAS-WT, 256 MUT) with a median follow up of 6.5 years after resection were evaluated. Fifty-four percent received adjuvant HAI. Tumor characteristics (synchronous disease, number of lesions, clinical-risk score, 2-stage hepatectomy) were significantly worse in the HAI group; however, there were more patients with resected extrahepatic metastases in the no-HAI group. In KRAS-WT tumors, 5-year survival was 78% for patients treated with HAI versus 57% for patients without HAI [hazard ratio (HR) 0.51, P < 0.001]. In KRAS-MUT tumors, 5-year survival was 59% for patients treated with HAI versus 40% for patients without HAI (HR 0.56, P < 0.001). On multivariate analysis, HAI remained associated with improved OS (HR 0.53, P < 0.002) independent of KRAS status and other clinicopathologic factors.

CONCLUSION

Adjuvant HAI after resection of CRLM is independently associated with improved outcomes regardless of KRAS mutational status. Adjuvant HAI may mitigate the worse outcomes seen in patients with resectable KRAS-MUT CRLM.

Abstract PR07: MSI detection in plasma cfDNA: MSI as a marker of disease burden

Lynch syndrome (LS), an inherited predisposition syndrome associated with an increased risk of colorectal, endometrial, and other cancers, is characterized by germline mutations in mismatch repair pathway genes, which typically lead to microsatellite instability (MSI) in the resulting tumors. The FDA approval of pembrolizumab for all advanced MSI-H solid tumors has led to increasing MSI assessment. The presence of MSI in LS-associated tumors provides a unique and transformative opportunity for early detection and disease monitoring in these patients. Here we describe an approach to detect MSI from plasma cfDNA using MSK-ACCESS, a custom capture “liquid biopsy” approved for clinical use by the NY State Department of Health. In addition to frequently mutated exons of 129 genes, MSK-ACCESS also includes 165 highly informative microsatellite loci, selected from over 1,000 microsatellite regions based on &gt;25,000 tumors sequenced using MSK-IMPACT, an FDA-authorized tumor sequencing panel. A key challenge in detecting MSI from cfDNA is the lack of ground truth in these samples, as cfDNA obtained from patients with MSI-high tumors may not always exhibit sufficient tumor-derived DNA fragments. To address this, we developed a machine learning approach for cfDNA analysis trained on orthogonally validated tumors sequenced via MSK-IMPACT. We present Allelic Distance-based Microsatellite Instability Estimator (ADMIE), an approach to translate deviation in tumor/cfDNA from normal/buffy coat DNA at individual microsatellite loci to a binary MSI call. ADMIE achieved a cross-validation precision of 1.00 +/- 0.02 and recall of 0.99 +/- 0.07. We ran this on 44 plasma samples collected from over 30 patients with MSI tumors including colorectal, prostate, and gastric cancers across multiple time points. We also evaluated plasma from 70 patients with known MSS tumors and 46 healthy controls. None of the cfDNA from healthy controls or patients with MSS tumors were found to be MSI positive, indicating high specificity. To establish our limit of detection, we performed in silico dilution experiments leveraging patient samples and MSI signal of biologic origin to simulate different tumor fractions, establishing our limit of detection at 1%. Among patients with MSI-high tumors, we found the presence and magnitude of MSI in the cfDNA to be correlated with measurable response to treatment with immunotherapy. In these patients, we detected MSI in the cfDNA of 6/8 samples where at least one mutation was detectable in plasma above 0.2% at baseline. Among the 4/6 patients for whom we had additional time points post treatment, we did not detect any mutations or evidence of MSI. In one patient, MSK-ACCESS indicated the presence of a second primary tumor based on the detection of MSI and mutations in cfDNA completely independent from those identified in the previously sequenced tumor. Our results suggest that MSI can be reliably detected in cfDNA using MSK-ACCESS and the MSI signature can represent a marker of occult metastatic disease in LS.

This abstract is also being presented as Poster A54.

Citation Format: Preethi Srinivasan, Alicia Latham, Zalak Patel, John Ziegler, Maysun Hasan, Juber A. Patel, Ian Johnson, Ronak Shah, Fanli Meng, Xiaohong Jing, Grittney Tam, Rose Brannon, Andrea Cercek, Ahmet Zehir, Brian Houck-Loomis, Dana Tsui, Zsofia Stadler, Michael F. Berger. MSI detection in plasma cfDNA: MSI as a marker of disease burden [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr PR07.

Phase I monotherapy dose escalation of RGX-202, a first-in-class oral inhibitor of the SLC6a8/CKB pathway, in patients with advanced gastrointestinal (GI) solid tumors

3504

Background: About 65% of advanced colorectal cancer (CRC) patients (pts) have creatine kinase B (CKB) expressing tumors. CKB expressing (CKB+) GI cancer cells import creatine via the creatine transporter SLC6a8 and utilize it to generate intracellular ATP. RGX-202, a small molecule inhibitor of SLC6a8, reduces intracellular creatine and ATP levels, leading to apoptosis. RGX-202 treatment triggers complete tumor regressions in multiple CKB+ preclinical models, including KRAS mutant CRC. Methods: RGX-202-001 is a phase I escalation/expansion study of RGX-202 +/- FOLFIRI in pts with advanced GI tumors. The primary safety objective during dose escalation is to identify the maximum tolerated dose (MTD), or the maximum tested dose at which multiple dose-limiting toxicities (DLTs) are not observed. The primary efficacy objective is to estimate the antitumor activity of RGX-202 by RECIST. Results: As of January 31, 2020, 17 pts have been treated in 4 single agent dose escalation cohorts: 600 mg BID (3 pts), 1200 mg BID (4 pts), 2400mg BID (5 pts) and 3600mg BID (5pts) given continuously. No DLTs were observed and an MTD was not reached. Treatment-related adverse events (TRAEs) occurring in > 2 pts are shown in the Table. There were no Grade 4 TRAEs. At the highest dose, 2 of 3 CRC pts had prolonged disease control: a patient with a KRAS G13D mutant cancer had SD for 14 weeks; and a patient with KRAS G12V mutant (MSS) cancer had a confirmed PR ongoing at 30 weeks. Exposure to RGX-202 was greater than dose-proportional and the average AUC0-24 ranged from ~15,700 ng-hr/mL in cohort 1 to 241,097 ng-hr/mL in in Cohort 4. Serum and urine creatine levels, pharmacodynamic markers of SLC6a8 inhibition, correlated with systemic exposure to RGX-202. Conclusions: Among 17 patients treated with single agent therapy, no DLTs occurred; notably, exposures predicted to be sufficient to inhibit human tumor growth from preclinical models were achieved along with concomitant pharmacodynamic effects. These data, along with a durable PR observed in the highest dose cohort, support further development of RGX-202. Consequently, dose escalation in combination with FOLFIRI in patients with advanced GI cancers is underway with plans for expansion in CKB+ CRC pts. Clinical trial information: NCT03597581 . [Table: see text]

Peritoneal mesotheliomas characterized by less cell-cycle alterations and more TRAF7 alterations than malignant pleural mesotheliomas

9059

Background: While peritoneal mesotheliomas (PM) are clinically distinct from malignant pleural mesotheliomas (MPM) it is unknown if genetic alterations reflect these differences. Here we report the molecular alterations and clinicopathologic characteristics of a prospectively collected PM cohort as compared to MPM. Methods: Patients with PM (n = 59) and targeted next generation sequencing (NGS; MSK-IMPACT) from January 2014 to January 2019 were assessed and followed through February 2020. Germline variants were analyzed in consented patients. NGS was compared to patients with MPM (n = 194) assessed in the same time interval. Results: Median age at diagnosis was 61 (range: 20-77), 56% were women (n = 33), and 92% had epithelioid histology (n = 54). 66% had ascites (n = 39) and 24% developed extra-abdominal metastases (n = 14; including lung, pleura, and mediastinum). 68% (n = 40) underwent surgical debulking and 80% (n = 47) had infusional therapy (median lines: 3) including platinum/pemetrexed (n = 38), EPIC (n = 22), HIPEC (n = 15), and immunotherapy (n = 16). The median overall survival (OS) from diagnosis was 5.4 years (median follow up 3.5 years). The median tumor mutation burden (TMB) was 1.8 mut/Mb (range: 0-14.9) in PM vs 2.0 mut/Mb (range: 0-31.5) in MPM (p = 0.049). More patients with PM had TRAF7 alterations than in MPM (5/59 vs 3/194; p = 0.02) while fewer had CDKN2A/ CDKN2B (4 vs 55; p = 0.0004). All patients with TRAF7 altered PM had well-differentiated papillary epithelioid histology. There was no difference in the prevalence of other common alterations such as BAP1 (32 vs 98; p = 0.66), NF2 (12 vs 55, p = 0.24), SETD2 (11 vs 24; p = 0.28), and TP53 (9 vs 28; p = 0.84) in PM vs MPM respectively. Patients with BAP1-altered PM had shorter OS (4.6 vs 9.8 years; HR 2.6, 95% CI 1.1-6.4; p = 0.04) while TRAF7-altered PM had improved OS (not reached vs 4.8 years; HR 0.3, 95% CI 0.1-0.9; p = 0.04) compared to wild type. 13% (4/30) of patients with PM had pathogenic variants on germline NGS ( POT1 I78T, MUTYH R109Y, BAP1 E402*, APC I1037K). Conclusions: NGS confirms the distinct biology of PM compared to MPM. Specifically, the former shows fewer cell cycle ( CDKN2) alterations compared to MPM. In contrast to MPM, BAP1 alteration was associated with shorter survival. As previously described, we found enrichment of TRAF7 in well differentiated papillary epithelioid PM associated with improved survival but notably some TRAF7 alterations were identified in poorly differentiated MPM. Consistent with other reports, the prevalence of germline alterations was 13%.

Do differences in the microbiome explain early onset in colon cancer?

e16070

Background: Intestinal dysbiosis has been hypothesized as a possible etiology of the increasing incidence of early-onset colon cancer (EO-CC). Here, we compare the microbiome signature in nonmetastatic, microsatellite stable (MSS) EO-CC to average-onset colon cancer (AO-CC). Methods: Specimens from patients with resected stage I-III MSS colon cancer from 2014-2019 were sequenced by MSK-IMPACT, a large panel next generation sequencing (NGS) assay. A validated technique using non-human read sequences from NGS analysis was used to identify the microbial species in tumor tissue. The tumor microbial alpha diversity and differentially abundant microbiome were compared between patients younger than 40 years (EO-CC) with those older than 60 years (AO-CC). Results: Of 275 patients with MSS, 24 (mean 33.6, range 24-39) and 114 patients (mean 70, range 61-90) had EO-CC and AO-CC, respectively. There was no significant difference in clinicopathological features including gender, tumor stage and neoadjuvant treatment between the two groups. EO-CC was more likely to present with left sided disease compared to AO-CC (81% vs. 45%, p = 0.001). There was no significant difference in the tumor microbial diversity (alpha diversity) between the EO-CC and AO-CC (pShannon= 0.95). Although there was a relative abundance of microbial species from bacterial phylum such as Actinobacteria, Deinococcus-Thermus, α-proteobacteria, γ-proteobacteria and δ-proteobacteria in EO-CC compared to AO-CC, this difference was not significant after controlling for multiple comparisons (Table). Conclusions: Our analysis did not reveal a significant difference between EO-CC and AO-CC in both the abundance and diversity of tumor microbial species, suggesting intestinal dysbiosis may not be a major driver in early onset colorectal cancer pathogenesis. However, additional studies with a larger sample size are warranted for further analysis and subgroup comparison. [Table: see text]

A phase II study of induction PD-1 blockade in subjects with locally advanced mismatch repair-deficient rectal adenocarcinoma

TPS4123

Background: The treatment of patients with locally advanced rectal cancer includes total neoadjuvant therapy with chemotherapy, chemoradiation followed by surgery. While most rectal cancers respond to combination induction chemotherapy, patients with mismatch repair deficient (dMMR) or MSI-H tumors have a significantly higher chance of progression with this treatment regimen. dMMR or MSI-H tumors have shown remarkable responses to PD-1 blockade, but the effect of neoadjuvant checkpoint inhibition has not been well studied. In this trial we will determine the pathologic complete response rate (pCR) of neoadjuvant anti-PD-1 blockade followed by standard chemoradiation in dMMR or MSI-H locally advanced rectal cancer. We hypothesize that treatment naïve dMMR or MSI-H rectal cancers will achieve a robust clinical response to PD-1 blockade and that the total neodjuvant therapy with PD-1 blockade followed by chemoradiation will improve pCR rates. Methods: Eligible patients ≥18 years of age with Stage II (T3-4, N-) or Stage III (any T, N+) histologically confirmed dMMR or MSI-H (by NGS) rectal adenocarcinoma will be enrolled. Patients will receive TSR-042 (500mg IV) every 3 weeks for a maximum of 8 cycles (6 months of treatment). Imaging, internal endoscopic exam and ctDNA blood draw will be performed at 6 weeks and every 3 months during induction anti-PD-1 treatment. Adverse events and surgical complications will be graded according to the NCI CTCAE v5 and the Clavien-Dindo classification, respectively. Following neoadjuvant checkpoint blockade, patients will undergo conventional chemoradiotherapy followed by surgical resection. The primary endpoint is pathologic complete response compared with historical control in pMMR patients. Patients will be followed up every 6 months for assessment of disease-free survival for up to five years. Clinical trial information: NCT04165772 .

Colorectal cancer statistics, 2020

Colorectal cancer (CRC) is the second most common cause of cancer death in the United States. Every 3 years, the American Cancer Society provides an update of CRC occurrence based on incidence data (available through 2016) from population-based cancer registries and mortality data (through 2017) from the National Center for Health Statistics. In 2020, approximately 147,950 individuals will be diagnosed with CRC and 53,200 will die from the disease, including 17,930 cases and 3,640 deaths in individuals aged younger than 50 years. The incidence rate during 2012 through 2016 ranged from 30 (per 100,000 persons) in Asian/Pacific Islanders to 45.7 in blacks and 89 in Alaska Natives. Rapid declines in incidence among screening-aged individuals during the 2000s continued during 2011 through 2016 in those aged 65 years and older (by 3.3% annually) but reversed in those aged 50 to 64 years, among whom rates increased by 1% annually. Among individuals aged younger than 50 years, the incidence rate increased by approximately 2% annually for tumors in the proximal and distal colon, as well as the rectum, driven by trends in non-Hispanic whites. CRC death rates during 2008 through 2017 declined by 3% annually in individuals aged 65 years and older and by 0.6% annually in individuals aged 50 to 64 years while increasing by 1.3% annually in those aged younger than 50 years. Mortality declines among individuals aged 50 years and older were steepest among blacks, who also had the only decreasing trend among those aged younger than 50 years, and excluded American Indians/Alaska Natives, among whom rates remained stable. Progress against CRC can be accelerated by increasing access to guideline-recommended screening and high-quality treatment, particularly among Alaska Natives, and elucidating causes for rising incidence in young and middle-aged adults.

Management of Locally Advanced Rectal Cancer During The COVID-19 Pandemic: A Necessary Paradigm Change at Memorial Sloan Kettering Cancer Center

The COVID-19 pandemic will consume significant health care resources. Given the concerns for rapidly increasing infection rates in the United States, impending staffing shortages, and the potential for resource reallocation, we rapidly reevaluated our rectal cancer practice policies during this public health emergency. Before the pandemic, we commonly used total neoadjuvant therapy with a strong preference for long-course chemoradiation. In the setting of the ongoing pandemic, we now mandate short-course radiation therapy (SCRT). Despite multiple randomized trials demonstrating no difference in locoregional recurrence, distant recurrence, or overall survival between SCRT and long-course chemoradiation, the adaptation of SCRT in the United States has been low given concerns for less tumor downstaging and increased toxicity. In the setting of the ongoing and likely prolonged COVID-19 pandemic, we feel that these concerns must be reevaluated, because SCRT presents a well-validated alternative that will allow us to meet the needs of a greater number of potentially curable patients at a time when resources are severely and acutely constrained.

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.

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.

Coaltered Ras/B-raf and TP53 Is Associated with Extremes of Survivorship and Distinct Patterns of Metastasis in Patients with Metastatic Colorectal Cancer

PURPOSE

We aimed to investigate genomic correlates underlying extremes of survivorship in metastatic colorectal cancer and their applicability in informing survival in distinct subsets of patients with metastatic colorectal cancer.

EXPERIMENTAL DESIGN

We examined differences in oncogenic somatic alterations between metastatic colorectal cancer cohorts demonstrating extremes of survivorship following complete metastasectomy: ≤2-year (n = 17) and ≥10-year (n = 18) survivors. Relevant genomic findings, and their association with overall survival (OS), were validated in two independent datasets of 935 stage IV and 443 resected stage I-IV patients.

RESULTS

In the extremes-of-survivorship cohort, significant co-occurrence of KRAS hotspot mutations and TP53 alterations was observed in ≤2-year survivors (P < 0.001). When validating these findings in the independent cohort of 935 stage IV patients, incorporation of the cumulative effect of any oncogenic Ras/B-raf (i.e., either KRAS, NRAS, or BRAF) and TP53 alteration generated three prognostic clusters: (i) TP53-altered alone (median OS, 132 months); (ii) Ras/B-raf-altered alone (65 months) or Ras/B-raf- and TP53 pan-wild-type (60 months); and (iii) coaltered Ras/B-raf-TP53 (40 months; P < 0.0001). Coaltered Ras/B-raf-TP53 was independently associated with mortality (HR, 2.47; 95% confidence interval, 1.91-3.21; P < 0.001). This molecular profile predicted survival in the second independent cohort of 443 resected stage I-IV patients. Coaltered Ras/B-raf-TP53 was associated with worse OS in patients with liver (n = 490) and lung (n = 172) but not peritoneal surface (n = 149) metastases. Moreover, coaltered Ras/B-raf-TP53 tumors were significantly more likely to involve extrahepatic metastatic sites with limited salvage options.

CONCLUSIONS

Genomic analysis of extremes of survivorship following colorectal cancer metastasectomy identifies a prognostic role for coaltered Ras/B-raf-TP53 and its association with distinct patterns of colorectal cancer metastasis.

Evolution of surgical management of gallbladder carcinoma and impact on outcome: results from two decades at a single-institution

BACKGROUND

The surgical approach to gallbladder cancer (GBCA) has evolved in recent years, but the impact on outcomes is unknown. This study describes differences in presentation, surgery, chemotherapy strategy, and survival for patients with GBCA over two decades at a tertiary referral center.

METHODS

A single-institution database was queried for patients with GBCA who underwent surgical evaluation and exploration and was studied retrospectively. Univariate logistic regression was used to assess the relationship between time and treatment. Univariate Cox proportional hazard regression assessed the association between year of diagnosis and survival.

RESULTS

From 1992 to 2015, 675 patients with GBCA were evaluated and 437 underwent exploration. Complete resection rates increased over time (p < 0.001). In those submitted to complete resection (n = 255, 58.4%), more recent years were associated with lower likelihood of bile duct resection and major hepatectomy but greater odds of neoadjuvant and adjuvant chemotherapy (p < 0.05). No significant association was found between year of diagnosis and OS or RFS (p > 0.05) for patients with complete resection.

CONCLUSION

Over the study period, GBCA treatment evolved to include fewer biliary and major hepatic resections with no apparent adverse impact on outcome. Further prospective trials, specifically limited to GBCA, are needed to determine the impact of adjuvant chemotherapy.

Adjuvant Hepatic Arterial Infusion Pump Chemotherapy After Resection of Colorectal Liver Metastases: Results of a Safety and Feasibility Study in The Netherlands

Background

The 10-year overall survival with adjuvant hepatic arterial infusion pump (HAIP) chemotherapy after resection of colorectal liver metastases (CRLMs) was 61% in clinical trials from Memorial Sloan Kettering Cancer Center. A pilot study was performed to evaluate the safety and feasibility of adjuvant HAIP chemotherapy in patients with resectable CRLMs.

Study Design

A phase II study was performed in two centers in The Netherlands. Patients with resectable CRLM without extrahepatic disease were eligible. All patients underwent complete resection and/or ablation of CRLMs and pump implantation. Safety was determined by the 90-day HAIP-related postoperative complications from the day of pump placement (Clavien–Dindo classification, grade III or higher) and feasibility by the successful administration of the first cycle of HAIP chemotherapy.

Results

A total of 20 patients, with a median age of 57 years (interquartile range [IQR] 51–64) were included. Grade III or higher HAIP-related postoperative complications were found in two patients (10%), both of whom had a reoperation (without laparotomy) to replace a pump with a slow flow rate or to reposition a flipped pump. No arterial bleeding, arterial dissection, arterial thrombosis, extrahepatic perfusion, pump pocket hematoma, or pump pocket infections were found within 90 days after surgery. After a median of 43 days (IQR 29–52) following surgery, all patients received the first dose of HAIP chemotherapy, which was completed uneventfully in all patients.

Conclusion

Pump implantation is safe, and administration of HAIP chemotherapy is feasible, in patients with resectable CRLMs, after training of a dedicated multidisciplinary team.

A rectal cancer organoid platform to study individual responses to chemoradiation

Rectal cancer (RC) is a challenging disease to treat that requires chemotherapy, radiation and surgery to optimize outcomes for individual patients. No accurate model of RC exists to answer fundamental research questions relevant to patients. We established a biorepository of 65 patient-derived RC organoid cultures (tumoroids) from patients with primary, metastatic or recurrent disease. RC tumoroids retained molecular features of the tumors from which they were derived, and their ex vivo responses to clinically relevant chemotherapy and radiation treatment correlated with the clinical responses noted in individual patients' tumors. Upon engraftment into murine rectal mucosa, human RC tumoroids gave rise to invasive RC followed by metastasis to lung and liver. Importantly, engrafted tumors displayed the heterogenous sensitivity to chemotherapy observed clinically. Thus, the biology and drug sensitivity of RC clinical isolates can be efficiently interrogated using an organoid-based, ex vivo platform coupled with in vivo endoluminal propagation in animals.

Changes in the multidisciplinary management of rectal cancer from 2009 to 2015 and associated improvements in short-term outcomes

AIM

Significant recent changes in management of locally advanced rectal cancer (LARC) include preoperative staging, use of extended neoadjuvant therapies and minimally invasive surgery (MIS). This study was aimed at characterizing these changes and associated short-term outcomes.

METHOD

We retrospectively analysed treatment and outcome data from patients with T3/4 or N+ LARC ≤ 15 cm from the anal verge who were evaluated at a comprehensive cancer centre in 2009-2015.

RESULTS

In total, 798 patients were identified and grouped into five cohorts based on treatment year: 2009-2010, 2011, 2012, 2013 and 2014-2015. Temporal changes included increased reliance on MRI staging, from 57% in 2009-2010 to 98% in 2014-2015 (P < 0.001); increased use of total neoadjuvant therapy, from 17% to 76% (P < 0.001); and increased use of MIS, from 33% to 70% (P < 0.001). Concurrently, median hospital stay decreased (from 7 to 5 days; P < 0.001), as did the rates of Grade III-V complications (from 13% to 7%; P < 0.05), surgical site infections (from 24% to 8%; P < 0.001), anastomotic leak (from 11% to 3%; P < 0.05) and positive circumferential resection margin (from 9% to 4%; P < 0.05). TNM downstaging increased from 62% to 74% (P = 0.002).

CONCLUSION

Shifts toward MRI-based staging, total neoadjuvant therapy and MIS occurred between 2009 and 2015. Over the same period, treatment responses improved, and lengths of stay and the incidence of complications decreased.

Romiplostim Treatment of Chemotherapy-Induced Thrombocytopenia

PURPOSE

Chemotherapy-induced thrombocytopenia (CIT) leads to delay or reduction in cancer treatment. There is no approved treatment.

METHODS

We conducted a phase II randomized trial of romiplostim versus untreated observation in patients with solid tumors with CIT. Before enrollment, patients had platelets less than 100,000/μL for at least 4 weeks, despite delay or dose reduction of chemotherapy. Patients received weekly titrated romiplostim with a target platelet count of 100,000/μL or more, or were monitored with usual care. The primary end point was correction of platelet count within 3 weeks. Twenty-three patients were treated in a randomization phase, and an additional 37 patients were treated in a single-arm, romiplostim phase. Resumption of chemotherapy without recurrent CIT was a secondary end point.

RESULTS

The mean platelet count at enrollment was 62,000/μL. In the randomization phase, 14 of 15 romiplostim-treated patients (93%) experienced correction of their platelet count within 3 weeks, compared with one of eight control patients (12.5%; P < .001). Including all romiplostim-treated patients (N = 52), the mean platelet count at 2 weeks of treatment was 141,000/μL. The mean platelet count in the eight observation patients at 3 weeks was 57,000/μL. Forty-four patients who achieved platelet correction with romiplostim resumed chemotherapy with weekly romiplostim. Only three patients (6.8%) experienced recurrent reduction or delay of chemotherapy because of isolated CIT.

CONCLUSION

This prospective trial evaluated treatment of CIT with romiplostim. Romiplostim is effective in correcting CIT, and maintenance allows for resumption of chemotherapy without recurrence of CIT in most patients.

Association of Preoperative and Postoperative Serum Carcinoembryonic Antigen and Colon Cancer Outcome

Importance

Guidelines recommend measuring preoperative carcinoembryonic antigen (CEA) in patients with colon cancer. Although persistently elevated CEA after surgery has been associated with increased risk for metastatic disease, prognostic significance of elevated preoperative CEA that normalized after resection is unknown.

Objective

To investigate whether patients with elevated preoperative CEA that normalizes after colon cancer resection have a higher risk of recurrence than patients with normal preoperative CEA.

Design, Setting, and Participants

This retrospective cohort analysis was conducted at a comprehensive cancer center. Consecutive patients with colon cancer who underwent curative resection for stage I to III colon adenocarcinoma at the center from January 2007 to December 2014 were identified.

Exposures

Patients were grouped into 3 cohorts: normal preoperative CEA, elevated preoperative but normalized postoperative CEA, and elevated preoperative and postoperative CEA.

Main Outcomes and Measures

Three-year recurrence-free survival (RFS) and hazard function curves over time were analyzed.

Results

A total of 1027 patients (461 [50.4%] male; median [IQR] age, 64 [53-75] years) were identified. Patients with normal preoperative CEA had 7.4% higher 3-year RFS (n = 715 [89.7%]) than the combined cohorts with elevated preoperative CEA (n = 312 [82.3%]) (P = .01) but had RFS similar to that of patients with normalized postoperative CEA (n = 142 [87.9%]) (P = .86). Patients with elevated postoperative CEA had 14.9% lower RFS (n = 57 [74.5%]) than the combined cohorts with normal postoperative CEA (n = 857 [89.4%]) (P = .001). The hazard function of recurrence for elevated postoperative CEA peaked earlier than for the other cohorts. Multivariate analyses confirmed that elevated postoperative CEA (hazard ratio [HR], 2.0; 95% CI, 1.1-3.5), but not normalized postoperative CEA (HR, 0.77; 95% CI, 0.45-1.30), was independently associated with shorter RFS.

Conclusions and Relevance

Elevated preoperative CEA that normalizes after resection is not an indicator of poor prognosis. Routine measurement of postoperative, rather than preoperative, CEA is warranted. Patients with elevated postoperative CEA are at increased risk for recurrence, especially within the first 12 months after surgery.

Genomic stratification beyond Ras/B-Raf in colorectal liver metastasis patients treated with hepatic arterial infusion

Background

Resection of colorectal liver metastases (CLM) can cure disease, but many patients with extensive disease cannot be fully resected and others recur following surgery. Hepatic arterial infusion (HAI) chemotherapy can convert extensive liver disease to a resectable state or decrease recurrence risk, but response varies and no biomarkers currently exist to identify patients most likely to benefit.

Methods

We performed a retrospective cohort study of CLM patients receiving HAI chemotherapy whose tumors underwent MSK‐IMPACT sequencing. The frequency of oncogenic alterations and their association with overall survival (OS) and objective response rate were analyzed at the individual gene and signaling pathway levels.

Results

Three hundred and seventy patients met inclusion criteria: 189 (51.1%) who underwent colorectal liver metastasectomy followed by HAI + systemic therapy (Adjuvant cohort), and 181 (48.9%) with unresectable CLM (Metastatic cohort) who received HAI + systemic therapy, consisting of 63 (34.8%) with extrahepatic disease and 118 (65.2%) with liver‐restricted disease. Genomic alterations were similar in each cohort, and no individual gene or pathway was significantly associated with objective response. Patients in the adjuvant cohort with concurrent Ras/B‐Raf alteration and SMAD4 inactivation had worse prognosis while in the metastatic cohort patients with co‐alteration of Ras/B‐Raf and TP53 had worse OS. Similar findings were observed in a validation cohort.

Conclusions

Concurrently altered Ras/B‐Raf and SMAD4 mutations were associated with worse survival in resectable patients, while concurrent Ras/B‐Raf and TP53 alterations were associated with worse survival in unresectable patients. The mutual exclusivity of Ras/B‐Raf, SMAD4, and TP53 may have prognostic value for CLM patients receiving HAI.