Genomic Landscape of Lynch Syndrome Colorectal Neoplasia Identifies Shared Mutated Neoantigens for Immunoprevention

BACKGROUND & AIMS

Lynch syndrome (LS) carriers develop mismatch repair-deficient neoplasia with high neoantigen (neoAg) rates. No detailed information on targetable neoAgs from LS precancers exists, which is crucial for vaccine development and immune-interception strategies. We report a focused somatic mutation and frameshift-neoAg landscape of microsatellite loci from colorectal polyps without malignant potential (PWOMP), precancers, and early-stage cancers in LS carriers.

METHODS

We generated paired whole-exome and transcriptomic sequencing data from 8 colorectal PWOMP, 41 precancers, 8 advanced precancers, and 12 early-stage cancers of 43 LS carriers. A computational pipeline was developed to predict, rank, and prioritize the top 100 detected mutated neoAgs that were validated in vitro using ELISpot and tetramer assays.

RESULTS

Mutation calling revealed >10 mut/Mb in 83% of cancers, 63% of advanced precancers, and 20% of precancers. Cancers displayed an average of 616 MHC-I neoAgs/sample, 294 in advanced precancers, and 107 in precancers. No neoAgs were detected in PWOMP. A total of 65% of our top 100 predicted neoAgs were immunogenic in vitro, and were present in 92% of cancers, 50% of advanced precancers, and 29% of precancers. We observed increased levels of naïve CD8+ and memory CD4+ T cells in mismatch repair-deficient cancers and precancers via transcriptomics analysis.

CONCLUSIONS

Shared frameshift-neoAgs are generated within unstable microsatellite loci at initial stages of LS carcinogenesis and can induce T-cell responses, generating opportunities for vaccine development, targeting LS precancers and early-stage cancers.

Exercise Training Reduces the Inflammatory Response and Promotes Intestinal Mucosa-Associated Immunity in Lynch Syndrome

PURPOSE

Lynch syndrome (LS) is a hereditary condition with a high lifetime risk of colorectal and endometrial cancers. Exercise is a non-pharmacologic intervention to reduce cancer risk, though its impact on patients with LS has not been prospectively studied. Here, we evaluated the impact of a 12-month aerobic exercise cycling intervention in the biology of the immune system in LS carriers.

PATIENTS AND METHODS

To address this, we enrolled 21 patients with LS onto a non-randomized, sequential intervention assignation, clinical trial to assess the effect of a 12-month exercise program that included cycling classes 3 times weekly for 45 minutes versus usual care with a one-time exercise counseling session as control. We analyzed the effects of exercise on cardiorespiratory fitness, circulating, and colorectal-tissue biomarkers using metabolomics, gene expression by bulk mRNA sequencing, and spatial transcriptomics by NanoString GeoMx.

RESULTS

We observed a significant increase in oxygen consumption (VO2peak) as a primary outcome of the exercise and a decrease in inflammatory markers (prostaglandin E) in colon and blood as the secondary outcomes in the exercise versus usual care group. Gene expression profiling and spatial transcriptomics on available colon biopsies revealed an increase in the colonic mucosa levels of natural killer and CD8+ T cells in the exercise group that were further confirmed by IHC studies.

CONCLUSIONS

Together these data have important implications for cancer interception in LS, and document for the first-time biological effects of exercise in the immune system of a target organ in patients at-risk for cancer.

Gastric Myeloid Sarcoma

Most gastric cancers are adenocarcinomas, but other malignancies can arise in the stomach. Patients with leukemia may develop myeloid sarcoma (MS) in the gastrointestinal tract. Our patient was a 68-year-old woman who was initially diagnosed with acute myeloid leukemia and underwent a matched unrelated stem cell transplantation. She was in remission for 10 years before developing a rare case of gastric MS without acute myeloid leukemia. She had partial response to chemotherapy but ultimately died because of infection. Gastric MS has an incidence of less than 1%. Gastrointestinal involvement usually involves the small intestine and rarely the stomach.

Neoadjuvant Pembrolizumab in Localized Microsatellite Instability High/Deficient Mismatch Repair Solid Tumors

PURPOSE

Pembrolizumab significantly improves clinical outcomes in advanced/metastatic microsatellite instability high (MSI-H)/deficient mismatch repair (dMMR) solid tumors but is not well studied in the neoadjuvant space.

METHODS

This is a phase II open-label, single-center trial of localized unresectable or high-risk resectable MSI-H/dMMR tumors. Treatment is pembrolizumab 200 mg once every 3 weeks for 6 months followed by surgical resection with an option to continue therapy for 1 year followed by observation. To continue on study, patients are required to have radiographic or clinical benefit. The coprimary end points are safety and pathologic complete response. Key secondary end points are response rate and organ-sparing at one year for patients who declined surgery. Exploratory analyses include interrogation of the tumor immune microenvironment using imaging mass cytometry.

RESULTS

A total of 35 patients were enrolled, including 27 patients with colorectal cancer and eight patients with noncolorectal cancer. Among 33 evaluable patients, best overall response rate was 82%. Among 17 (49%) patients who underwent surgery, the pathologic complete response rate was 65%. Ten patients elected to receive one year of pembrolizumab followed by surveillance without surgical resection (median follow-up of 23 weeks [range, 0-54 weeks]). An additional eight did not undergo surgical resection and received less than 1 year of pembrolizumab. During the study course of the trial and subsequent follow-up, progression events were seen in six patients (four of whom underwent salvage surgery). There were no new safety signals. Spatial immune profiling with imaging mass cytometry noted a significantly closer proximity between granulocytic cells and cytotoxic T cells in patients with progressive events compared with those without progression.

CONCLUSION

Neoadjuvant pembrolizumab in dMMR/MSI-H cancers is safe and resulted in high rates of pathologic, radiographic, and endoscopic response, which has implications for organ-sparing strategies.

Phase II trial of weekly erlotinib dosing to reduce duodenal polyp burden associated with familial adenomatous polyposis

IMPORTANCE

Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal adenomas and cancer. Combination sulindac and erlotinib was previously shown to reduce duodenal polyp burden but was associated with a relatively high adverse event (AE) rate.

OBJECTIVE

To evaluate if a once weekly dosing schedule for erlotinib intervention improves the AE profile, while still providing efficacy with respect to reduced polyp burden, in participants with FAP.

DESIGN, SETTING AND PARTICIPANTS

Single-arm trial, enrolling 46 participants with FAP, conducted from October 2017 to September 2019 in eight academic cancer centres.

EXPOSURES

Participants self-administered 350 mg of erlotinib by mouth, one time per week for 6 months.

MAIN OUTCOMES AND MEASURES

Duodenal polyp burden (sum of polyp diameters) was assessed in the proximal duodenum by esophagogastroduodenoscopy performed at baseline and 6 months, with mean per cent change defined as the primary efficacy outcome of interest. Rate of grade 2-3 AEs was evaluated as a co-primary outcome. Secondary outcomes included changes in total duodenal polyp count, along with changes in lower gastrointestinal (GI) polyp burden and count (for participants examined by optional lower endoscopy).

RESULTS

Forty-six participants (mean age, 44.1 years (range, 18-68); women, 22 (48%)) were enrolled; 42 participants completed 6 months of intervention and were included in the per-protocol analysis. Duodenal polyp burden was significantly reduced after 6 months of weekly erlotinib intervention, with a mean per cent change of -29.6% (95% CI, -39.6% to -19.7%; p<0.0001). Similar results were observed in subgroup analyses defined by participants with advanced duodenal polyposis (Spigelman 3) at baseline (mean, -27%; 95% CI, -38.7% to -15.2%; p<0.0001). Post-intervention Spigelman stage was downstaged in 12% of the participants. Lower GI polyp number was also decreased after 6 months of intervention (median, -30.8%; IQR, -47.4% to 0.0%; p=0.0256). Grade 2 or 3 AEs were reported in 71.7% of subjects, with only two experiencing grade 3 toxicity at least possibly related to intervention.

CONCLUSION

In this single-arm, multi-centre trial of participants with FAP, erlotinib one time per week resulted in markedly lower duodenal polyp burden, and modestly reduced lower GI polyp burden, after 6 months of intervention. While AEs were still reported by nearly three-quarters of all participants, these events were generally lower grade and well-tolerated. These findings support further investigation of erlotinib as an effective, acceptable cancer preventive agent for FAP-associated GI polyposis.

TRIAL REGISTRATION NUMBER

NCT02961374.

Colorectal surveillance outcomes from an institutional longitudinal cohort of lynch syndrome carriers

Objective

Lynch Syndrome (LS) carriers have a significantly increased risk of developing colorectal cancer (CRC) during their lifetimes. Further stratification of this patient population may help in identifying additional risk factors that predispose to colorectal carcinogenesis. In most LS patients CRC may arise from adenomas, although an alternative non-polypoid carcinogenesis pathway has been proposed for PMS2 carriers. Using data from our institutional LS cohort, our aim was to describe our current colorectal screening outcomes with a focus on the incidence of adenomas in the context of different MMR genotypes and patient demographics such as gender, race, and ethnicity.

Design

We collected demographics, genetic, colonoscopy, and pathology results from a total of 163 LS carriers who obtained regular screening care at MD Anderson Cancer Center. Data were extracted from the electronic health records into a REDCap database for analysis. Logistic regressions were performed to measure the association between MMR variants and the likelihood of adenomas, advanced adenomas, and CRC. Then, we analyzed the cumulative incidences of these outcomes for the first 36 months following enrollment using Kaplan-Meier incidence curves, and Cox proportional hazard regressions.

Results

On multivariate analysis, age (≥45 years old) was associated with an increased risk of developing adenomas (P=0.034). Patients with a prior or active cancer status were less likely to develop adenomas (P=0.015), despite of the lack of association between surgical history with this outcome (P=0.868). We found no statistically significant difference in likelihood of adenoma development between MLH1 and MSH2/EPCAM, MSH6, and PMS2 carriers. Moreover, we observed no statistically significant difference in the likelihood of advanced adenomas or CRC for any measured covariates. On Cox proportional hazard, compared to MLH1 carriers, the incidence of adenomas was highest among MSH2/EPCAM carriers during for the first 36-months of follow-up (P<0.001). We observed a non-statistically significant trend for Hispanics having a higher and earlier cumulative incidence of adenomas compared to non-Hispanics (P=0.073). No MMR carrier was more likely to develop advanced adenomas. No difference in the incidence of CRC by MMR gene (P=0.198).

Conclusion

Screening recommendations for CRC in LS patients should be based on specific MMR variants and should also be tailored to consider patient demographics.

Role of Abdominal and Pelvic CT Scans in Diagnosis of Patients with Immunotherapy-Induced Colitis

Introduction:

Colitis is one of the most common immune-related adverse events in patients receiving immune checkpoint inhibitors. Although radiographic changes on computed tomography (CT), such as mild diffuse bowel thickening, mesenteric fat stranding, and mucosal enhancement, have been reported, the utility of CT in diagnosis of patients with suspected immune-related colitis is not well documented. The aim of this retrospective study was to determine the value of CT scans in diagnosis of immunotherapy-induced colitis.

Methods:

CT scans of the abdomen and pelvis of 34 patients receiving immunotherapy who had a clinical diagnosis of immunotherapy-induced colitis and 19 patients receiving immunotherapy without clinical symptoms of colitis (controls) were evaluated. Segments of the colon (rectum, sigmoid, descending, transverse, ascending, and cecum) were assessed independently by two abdominal imaging specialists, blinded to the clinical diagnosis. Each segment was assessed for radiographic signs such as mucosal enhancement, wall thickening, distension, and periserosal fat stranding. The presence of any of the signs was considered radiographic evidence of colitis.

Results:

CT findings suggestive of colitis was seen in 20 of 34 patients with symptoms of colitis and in 5 of 19 patients without symptoms of colitis. The sensitivity, specificity, positive predictive value, and negative predictive value for colitis on CT were 58.8%, 73.7%, 80%, and 50%, respectively.

Conclusions:

We found that CT had a low sensitivity, specificity, and negative predictive value for the diagnosis of immunotherapy-induced colitis. We therefore conclude that CT has a limited role in the diagnosis of patients with suspected uncomplicated immune-related colitis.

Ibrutinib With Rituximab in First-Line Treatment of Older Patients With Mantle Cell Lymphoma

PURPOSE

Most patients with mantle cell lymphoma (MCL) are older. In this study, we investigated the efficacy and safety of a chemotherapy-free combination with ibrutinib and rituximab (IR) in previously untreated older patients with MCL (age ≥ 65 years).

METHODS

We enrolled 50 patients with MCL in this single-institution, single-arm, phase II clinical trial (NCT01880567). Patients with Ki-67% ≥ 50% and blastoid morphology were excluded. Ibrutinib was administered with rituximab up to 2 years with continuation of ibrutinib alone. The primary objective was to assess the overall response rate and safety of IR. In evaluable samples, whole-exome sequencing and bulk RNA sequencing from baseline tissue samples were performed.

RESULTS

The median age was 71 years (interquartile range 69-76 years). Sixteen percent of patients had high-risk simplified MCL international prognostic index. The Ki-67% was low (< 30%) in 38 (76%) and moderately high (≥ 30%-50%) in 12 (24%) patients. The best overall response rate was 96% (71% complete response). After a median follow-up of 45 months (interquartile range 24-56 months), 28 (56%) patients came off study for various reasons (including four progression, 21 toxicities, and three miscellaneous reasons). The median progression-free survival and overall survival were not reached, and 3-year survival was 87% and 94%, respectively. None of the patients died on study therapy. Notably, 11 (22%) patients had grade 3 atrial fibrillation. Grade 3-4 myelosuppression was seen in < 5% of patients. Differential overexpression of CCND1, BIRC3, BANK1, SETBP1, AXIN2, and IL2RA was noted in partial responders compared with patients with complete response.

CONCLUSION

IR combination is effective in older patients with MCL. Baseline evaluation for cardiovascular risks is highly recommended. Randomized trial is needed for definitive conclusions.

Combination of Sulindac and Bexarotene for Prevention of Intestinal Carcinogenesis in Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP) is a hereditary colorectal cancer syndrome, which results in the development of hundreds of adenomatous polyps carpeting the gastrointestinal tract. NSAIDs have reduced polyp burden in patients with FAP and synthetic rexinoids have demonstrated the ability to modulate cytokine-mediated inflammation and WNT signaling. This study examined the use of the combination of an NSAID (sulindac) and a rexinoid (bexarotene) as a durable approach for reducing FAP colonic polyposis to prevent colorectal cancer development. Whole transcriptomic analysis of colorectal polyps and matched normal mucosa in a cohort of patients with FAP to identify potential targets for prevention in FAP was performed. Drug-dose synergism of sulindac and bexarotene in cell lines and patient-derived organoids was assessed, and the drug combination was tested in two different mouse models. This work explored mRNA as a potential predictive serum biomarker for this combination in FAP. Overall, transcriptomic analysis revealed significant activation of inflammatory and cell proliferation pathways. A synergistic effect of sulindac (300 μmol/L) and bexarotene (40 μmol/L) was observed in FAP colonic organoids with primary targeting of polyp tissue compared with normal mucosa. This combination translated into a significant reduction in polyp development in Apc^Min/+ and Apc^LoxP/+-Cdx2 mice. Finally, the reported data suggest miRNA-21 could serve as a predictive serum biomarker for polyposis burden in patients with FAP. These findings support the clinical development of the combination of sulindac and bexarotene as a treatment modality for patients with FAP. PREVENTION RELEVANCE: This study identified a novel chemopreventive regimen combining sulindac and bexarotene to reduce polyposis in patients with FAP using in silico tools, ex vivo, and in vivo models. This investigation provides the essential groundwork for moving this drug combination forward into a clinical trial.

Safety and efficacy of neoadjuvant pembrolizumab in mismatch repair deficient localized/locally advanced solid tumors

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Background: Pembrolizumab (Pembro), anti-PD1 therapy, is FDA approved for refractory microsatellite instability high (MSI-H)/deficient mismatch repair (dMMR) advanced/metastatic solid tumors. The robust activity of anti-PD1 therapy in these tumors argues for a neoadjuvant organ-sparing approach. However, the role of anti-PD1 monotherapy in the neoadjuvant setting is unknown. Methods: This is a phase 2 open-label, single center trial (NCT04082572) of MSI-H/dMMR non-metastatic solid tumors with localized unresectable or high risk resectable (defined as ≥ 20% recurrence) with measurable disease per RECISTv1.1 and ECOG PS 0/1. Treatment is Pembro 200mg every 3 wks for 8 cycles (6 months) followed by surgical resection with option to continue therapy for 18 cycles (12 months) followed by observation. First restaging is at 6 wks and includes baseline and 3-week 70-gene ctDNA assessment. To continue on study, patients are required to have PR/CR, SD with tumor shrinkage or SD with decline in ctDNA [highest variant allele frequency (VAF) baseline mutation]. The co-primary endpoints are safety and pathological complete response (pCR). Key secondary endpoints are response rate and organ-sparing at one year for patients who declined surgery. Results: Between 12/2019 and 2/2021, 32 pts were enrolled and treated. Enrolment goal of 35 anticipated to be met by 4/2021. Baseline characteristics included 13 females, median age of 63 yrs (range 26 - 91), Lynch syndrome in 12 pts, BRAF V600E mutation in 11 pts. Tumor type included 24 CRC and 8 non-CRC (1 endometrial, 1 gastric, 1 meningeal, 2 duodenal, 1 ampullary, 2 pancreatic). At baseline disease was resectable in 23 (72%). Among 30 evaluable pts, best overall response rate was 77%: 30% CR (n = 9), 47% PR (n = 14), 20% SD (n = 6), 3% PD (n = 1). Only one pt progressed after initial SD of -18%. Median follow-up is 6.1 months (range 0.1 - 14). Among the 6 (20%) pts who underwent surgery, pCR was seen in 3 (50%). A non-operative approach (pembro for 12 months) has been chosen in 15 pts and 1-year organ-sparing was seen in 2/2 evaluable pts. Treatment-related grade 3/4 immune adverse events (TRAE) were seen in 3 (9%) pts: grade 3 immune hepatitis (2) and grade 3 type 1 diabetes (1). Baseline ctDNA was positive in 17 (53%) pts with a median of 4 mutations per pt (1 - 35) and median highest VAF of 0.9% (range 0.3% to 38.2%). Among 26 pts with successful tumor tissue testing, median tumor mutations were 10.5, range 1 to 21 (Oncomine 134 gene panel). ctDNA decline at 3 weeks was seen in 14/17 (82%) patients. Luminal disease was present in 24 pts with endoscopic response of: CR in 13 (54%), major response 1, pending follow-up evaluation 6, not evaluated 3, and no response in 1. Conclusions: Neoadjuvant pembrolizumab is safe with encouraging clinical activity and this data suggests that a non-operative management for dMMR/MSI-H localized solid tumors should receive further investigation. Clinical trial information: NCT04082572.

Are current family-history based colorectal cancer screening guidelines adequate for early detection and potential prevention of young-onset cases?

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Background: Strategies to detect and prevent young-onset colorectal cancer (YOCRC, diagnosed under age 50) are critical. Established high-risk screening guidelines (SGs) aim to detect/prevent YOCRCs arising from hereditary syndromes. For non-hereditary YOCRCs, average-risk screening is being considered at an earlier age, but family history (FH)-based increased-risk screening has been poorly studied. We aimed to define the proportion of non-hereditary YOCRC with a FH, and to determine whether existing SGs could have detected/prevented these cases. Methods: 394 consecutive YOCRC patients presenting for surgical resection were reviewed for tumor MMR status, pedigree and genetic testing. Those with known/suspected hereditary syndrome (by phenotype, MMR status, and/or germline mutation) were excluded (N = 65). Pedigrees (N = 329) were analyzed for first- or second-degree relatives (FDR, SDR) with CRC and the ages of diagnosis. The gap between the recommended age for FH-based CRC screening and the age of YOCRC diagnosis was calculated. Results: 89 (27%) non-hereditary YOCRC patients had a FH of CRC. The median age of diagnosis was 45; the tumors were mostly from the distal colon (22%) and rectum (60%), and stage III (48%) and IV (27%). Twenty-one (24%) patients had 22 FDRs with CRCs diagnosed at age 64 (median); and 71 (80%) patients had 92 SDRs with CRCs diagnosed at age 65 (median). Thirteen (15%) had a FH of YOCRC. The existing SGs consider 39 patients (44%) at increased-risk, and the remaining, average-risk (Table). Screening would have begun prior to the YOCRC diagnoses in 28 (31% [or 46, 52%]) patients. But YOCRC diagnosis preceded the recommended screening age in the remaining 61(69% [or 43, 48%]) patients by a median of 5.3 [or 3.9] years (Table). Conclusions: FH is found in 27% of the non-hereditary YOCRC patients; 15% has a FH of YOCRC. In nearly half of the patients, YOCRC was diagnosed several years earlier than the recommended age for FH-based screening, even assuming perfect SG adoption and starting average risk screening at age 45. Refining existing FH-based SGs can potentially be impactful.[Table: see text]

Longitudinal single-cell profiling reveals molecular heterogeneity and tumor-immune evolution in refractory mantle cell lymphoma

The mechanisms driving therapeutic resistance and poor outcomes of mantle cell lymphoma (MCL) are incompletely understood. We characterize the cellular and molecular heterogeneity within and across patients and delineate the dynamic evolution of tumor and immune cell compartments at single cell resolution in longitudinal specimens from ibrutinib-sensitive patients and non-responders. Temporal activation of multiple cancer hallmark pathways and acquisition of 17q are observed in a refractory MCL. Multi-platform validation is performed at genomic and cellular levels in PDX models and larger patient cohorts. We demonstrate that due to 17q gain, BIRC5/survivin expression is upregulated in resistant MCL tumor cells and targeting BIRC5 results in marked tumor inhibition in preclinical models. In addition, we discover notable differences in the tumor microenvironment including progressive dampening of CD8+ T cells and aberrant cell-to-cell communication networks in refractory MCLs. This study reveals diverse and dynamic tumor and immune programs underlying therapy resistance in MCL.

Abstract 17: Ex-vivo assessment of the effect of Simvastatin in intestinal epithelium of Lynch Syndrome patients

Background: Lynch Syndrome (LS) is a hereditary condition secondary to germline mutations in DNA mismatch repair (MMR) genes, which predisposes patients to develop different tumor types but mainly colorectal and endometrial cancers. Due to the genetic predisposition, chemopreventive strategies become critical in these individuals. One such chemopreventive compound, statin, a potent pharmacologic inhibitor of cholesterol biosynthesis, is known to exert other pleotropic effects such as modulation of cell proliferation, apoptosis, and inflammation, mainly due to inhibition of the mevalonate pathway. Although, chemoprevention studies in the past were performed in cancer stem cell models the effects have not been previously assessed in the physiologic and MMR-deficient stem cell niche. Here, we have successfully established ex-vivo cultures of crypt-villus structures (termed ‘mini-guts' or organoids) in order to interrogate the chemopreventive effects of statins in Lynch Syndrome patients.

Methods: Fresh endoscopic biopsy samples from a total of six LS patients followed at The University of Texas MD Anderson Cancer Center were obtained and ex-vivo organoid cultures were established. Each organoid line (passage &lt; P6) was treated with two different doses of Simvastatin (5 and 10 µM) or DMSO (control) for 48 hours. Total RNA was isolated from organoids treated with control and Simvastatin 10 µM and RNASeq analysis was performed using Illumina HiSeq 4000. Validation of several critical genes was performed by qRT-PCR assay.

Results: RNAseq analysis accounted for a total of 4,386 genes dysregulated in organoids treated with Simvastatin as compared to control. Stem cell markers, LGR5 and ASCL2, and differentiation markers, KRT20 (enterocytes) and MUC2 (goblet), were found to be induced by simvastatin. Gene Set Enrichment Analysis (GSEA) using Hallmark pathway gene sets showed significant enrichment for E2F target genes apart from canonical cholesterol homeostasis pathway. Ingenuity pathways analysis (IPA) revealed a list of top 10 genes which are upregulated/downregulated and implicated in cancer pathway. Validation of selected E2F Hallmark pathway genes (E2F1, TOP2A, Survivin, and KI-67) and IPA cancer pathway genes (KLF2, KLF6, EZH2, p57, and p21) showed a significant and dose dependent modulation upon treatment with Simvastatin.

Conclusions: Treatment with Simvastatin exhibited a profound effect on key genes involved in maintenance of stem cell niche in patient-derived organoids from LS. Simvastatin had a significant effect on E2F target genes implicated in regulation of cell cycle and proliferation via modulation of Ki-67, TOP2A, and Survivin. Along with increase in cyclin-dependent kinase inhibitor p21, there was significant induction of p57, a candidate tumor suppressor gene. Hence, Simvastatin, while it maintains the stem niche, exerts its anti-proliferative effects by specifically modulating genes involved in cell cycle and apoptosis.

Citation Format: Prashant Bommi, Wenhui Wu, Laura Reyes, Kyera Evans, Selvi Thirumurthi, Patrick Lynch, Krishna Sinha, Eduardo Vilar. Ex-vivo assessment of the effect of Simvastatin in intestinal epithelium of Lynch Syndrome patients [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 17.

Efficacy of venetoclax in high risk relapsed mantle cell lymphoma (MCL) - outcomes and mutation profile from venetoclax resistant MCL patients

Venetoclax is effective in relapsed patients with mantle cell lymphoma (MCL). Mechanisms of resistance to venetoclax in MCL are poorly understood. We describe the clinical outcomes and genomic characteristics of 24 multiply relapsed patients (median of five prior lines of therapy) who received venetoclax-based therapies; 67% had progressed on BTK inhibitors (BTKi) and 54% had blastoid or pleomorphic histology. Median follow up after venetoclax treatment was 17 months. The overall response rate was 50% and complete response (CR) rate was 21%, 16 patients had progressed and 15 died. The median progression free, overall and post venetoclax survival were 8, 13.5 and 7.3 months respectively. Whole-exome sequencing (WES) was performed on samples collected from seven patients (including five pairs; before starting venetoclax and after progression on venetoclax). The SMARCA4 and BCL2 alterations were noted only after progression, while TP53, CDKN2A, KMT2D, CELSR3, CCND1, NOTCH2 and ATM were altered 2-4-fold more frequently after progression. In two patients with serial samples, we demonstrated clonal evolution of novel SMARCA4 and KMT2C/D mutations at progression. Mutation dynamics in venetoclax resistant MCL is demonstrated. Our data indicates that venetoclax resistance in MCL is predominantly associated with non-BCL2 gene mutations. Further studies are ongoing in MCL patients to evaluate the efficacy of venetoclax in combination with other agents and understand the biology of venetoclax resistance in MCL.

Cap-fitted endoscopic mucosal resection of ≥ 20 mm colon flat lesions followed by argon plasma coagulation results in a low adenoma recurrence rate

Background and study aims  Endoscopic mucosal resection (EMR) is increasingly used for the treatment of large colonic polyps (≥ 20 mm). A drawback of EMR is local adenoma recurrence. Therefore, we studied the impact of argon plasma coagulation (APC) of the EMR edge on local adenoma recurrence. Patients and methods  This was a retrospective study of patients with laterally spreading tumors (LST) ≥ 20 mm, who underwent EMR from January 2009 to August 2018 and follow-up endoscopic assessment. A cap-fitted endoscope was used to assess completeness of resection by systematically inspecting the EMR defect for any macroscopic disease. This was followed by forced APC of the resection edge followed by clip closure of the defect. Surveillance colonoscopy was performed at 6 months after resection to detect recurrence. Results  Two hundred forty-six patients met the inclusion criteria. Most were female (53 %) and white (80 %), with a Median age of 64 years. Median polyp size was 35 mm (interquartile range, 30-45 mm). Most polyps were located in the right colon (77 %) and were removed by piecemeal EMR (70 %). Eleven patients (5 %) had residual tumor at the resection site. Conclusions  We observed low adenoma recurrence after argon plasma coagulation of the EMR edge with a cap fitted colonoscope in patients with LST ≥ 20 mm of the colon, which requires further validation in a randomized controlled study.

Metachronous colorectal pathology among survivors of young-onset colorectal cancer: Implications for postresection colonoscopic surveillance

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Background: Patients with sporadic young-onset colorectal cancer (CRC) are postulated to have a more biologically active colorectum prone to malignant transformation earlier in life. It is unknown whether there is elevated risk for metachronous colorectal pathology after the index cancer. We aimed to define this risk, to inform their post-resection endoscopic surveillance. Methods: Consecutive CRC patients (aged 18-50, n = 728) were prospectively followed after surgical resection between 2009 and 2017. Patients presenting with hereditary CRC, recurrent disease, or without endoscopy follow-up were excluded. All endoscopy records were subjected to natural language processing and further reviewed. Metachronous colorectal pathology of interest included: high-risk adenoma (≥1cm in size, > 3 in number, or tubulovillious/high-grade dysplasia histology), second CRC, and endoscopically detectable local recurrence. Results: During a 48-month (median) follow-up, 457 patients underwent 1,192 person-years of colonoscopic follow-up. The median age at CRC diagnosis was 44 years. Disease arose from the proximal colon in 9.4%, distal colon in 23.0% and rectum in 67.6%, and was stages I/II in 191 (41.8%), III in 185 (40.4%), and IV in 81 (17.7%). The majority (95.8%) underwent segmental resection, while the remainder had extended resections for synchronous pathology not amendable to preoperative endoscopic clearance. The overall incidence of metachronous pathology was 32 per 1000 person-years: 31 patients developed high-risk adenomas (6.8%), 1 had a second CRC (0.2%), and 7 had luminal recurrences (1.5%). The median time to metachronous pathology was 13.9 (IQR: 11.8-33.1) months, with 21 (53.8%) detected between 12 and 48 months post-resection. Conclusions: For young-onset CRC survivors, the incidence of metachronous colorectal pathology was 32 per 1000 person-years of follow-up. Given the time pattern of detection, adding an interval colonoscopy between the current recommended post-resection surveillance at 12 and 48 months may be beneficial.

[Table: see text]

Clinical characteristics of colitis induced by taxane-based chemotherapy

Background:

Limited data are available concerning the clinical features of toxic gastrointestinal (GI) effects of taxane-based therapy. We describe the clinical, endoscopic and histologic features of taxane-induced colitis.

Methods:

This retrospective study included cancer patients who received taxane therapy and underwent colonoscopy for GI symptoms from 2000-2018.

Results:

Of the 45,527 patients who received taxane therapy during the study period, 76 (0.2%) met the inclusion criteria. Most patients (54%) received paclitaxel, 37% docetaxel, and 9% nab-paclitaxel. The median time from taxane therapy initiation to colitis symptom onset was 31 days. The median duration of colitis symptoms was 30 days. Colitis treatment comprised immunosuppressive therapy in 8 patients (11%), antibiotics in 17 (22%), antimotility agents in 18 (24%), and octreotide or somatostatin in 2 (3%). Thirty-five patients (46%) required hospitalization and seven (9%) required admission to the intensive care unit (ICU). Endoscopy revealed mucosal ulceration in 19 patients (25%), nonulcerative inflammation in 32 (42%), and normal findings in 25 (33%). Seventeen patients (22%) had features of lymphocytic colitis. One patient had spontaneous colonic perforation that required surgical intervention. Colitis symptoms recurred in 7 patients (9%) after initial improvement. Patients who received nab-paclitaxel developed GI toxicity earlier (P=0.003), required colitis-related hospitalization more frequently (P=0.005), and received intravenous fluids more frequently (P=0.025), compared with patients who received other taxanes.

Conclusions:

Taxane-related colitis can present with significant inflammation on colonoscopy, and in a minority of patients as microscopic colitis. Taxane-induced colitis, although uncommon, can lead to ICU admission and colonic perforation.

Safety and efficacy of metal stents for malignant colonic obstruction in patients treated with bevacizumab

BACKGROUND AND AIMS

The aim of this study was to examine clinical outcomes and adverse events (AEs) of self-expandable metal stents (SEMSs) in the management of malignant colonic obstruction (MCO).

METHODS

Patients with SEMSs for MCO treated at our institution from 2007 to 2016 were included. Clinical success was defined as successful oral intake after the procedure and technical success as stent deployment across the stricture in the desired location.

RESULTS

Of 199 patients, the mean age was 58, 54% were men, and 99% had stage IV cancer. MCO etiology was colorectal cancer in 82% and extrinsic compression in 17%. Technical success was achieved in 99.5% and clinical success in 89%. The SEMSs were palliative in 97% and were a bridge to surgery in 4%. MCO occurred in the left side of the colon in 90%, transverse in 4.5%, and ascending colon in 5.5%. SEMSs were placed in curved segments in 30% and straight segments in 70%. Tandem SEMSs were required in 27 patients. Forty-six patients had 48 AEs (24%), including 2% periprocedure, 15% postprocedure, and 83% after 72 hours. Stent-related AEs (n = 25) included persistent obstruction (n = 14), occlusion (n = 10), and failure of expansion (n = 1). Procedural AEs (n = 23) included minor bleeding (n = 2), perforations (n = 4), abdominal pain (n = 12), stent migration (n = 4), and respiratory insufficiency (n = 1). Repeat procedures were performed in 21 of 46 patients. After SEMSs, 48 patients underwent surgery, including resection with primary anastomosis (n = 8), resection with definitive stoma (n = 18), and diverting stoma without resection (n = 19). Mean time to surgery after SEMS placement was 175 days. Postsurgical AEs occurred in those with resections (leak, 2; infection, 2). Of 104 receiving bevacizumab, 22% had AEs, including 1 perforation compared with 3 in the nonbevacizumab group (P = .549). Mean overall survival was 5.6 months. Extrinsic compression and curved strictures were associated with poor clinical success by univariate analysis and etiology (noncolonic with poor outcome) by multivariate analysis.

CONCLUSIONS

SEMSs for MCO has high technical but suboptimal clinical success. Curved strictures and extrinsic compression are associated with poor outcomes. The perforation rate was not higher in the bevacizumab compared with the nonbevacizumab group, although this should be further validated in a larger population.

Exploring the genetic basis of Lynch-like syndrome through paired germline and tumor exome sequencing

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Background: Lynch-like syndrome (LLS) is characterized by a diagnosis of mismatch repair deficient (dMMR) malignancy where somatic bi-allelic mutations in canonical MMR pathway genes ( MLH1, MSH2, MSH6, PMS2) have been identified as the main cause. Yet, a substantial proportion of cases remain unexplained by MMR somatic bi-allelic events or germline mutations. We hypothesize that LLS cases with young-onset cancers carry cryptic germline alterations in other pathways. To explore this contribution, we performed analyses of the germline and tumor mutation landscapes in LLS patients diagnosed with dMMR cancers. Methods: 18 probands with young-onset (age <50 years) dMMR colorectal or uterine cancers were selected from a familial cancer registry. The absence of deleterious germline MMR mutation and/or somatic MLH1inactivation was confirmed by standard clinical testing. We performed whole-exome sequencing (Illumina HiSeq) of germline (peripheral blood) DNA. Variant calls, quality-control, allele-frequency filtering (<1% in reference cohorts), and in silicoannotation were performed using the GATK and polyphen/SIFT tools. Pathway analysis was performed using the DAVID suite. For 16 of 18 patients, targeted exon sequencing of 408 cancer-related genes was performed on paired tumor/normal tissue samples (Ion Torrent AmpliSeq) and analyzed with VarScan 2. Results: 237,055 rare germline variants were detected in our cohort. We enriched a subset of 758 variants with putative frameshift (45.1%), stop gain or loss (25%), or splice site alteration (29.9%). Pathway analysis of genes altered by this subset revealed excess events in DNA damage repair (e.g. ERCC5, POLM, POLN, EXO5) and mRNA splicing (e.g. SCAF1, SRSF4) pathways. Preliminary analysis of somatic mutations profiles shows frequent alteration of known drivers including APC(64%) and NOTCH1(36%). Conclusions: Our exploratory analysis provides novel evidence that LLS patients may harbor an excess of deleterious germline mutations in DNA damage repair- and mRNA splicing-related genes. Future studies will identify genes which are targeted by both germline and somatic mutation with the goal of nominating putative causal genes. Defining additional mechanisms of dMMR in LLS cancers may help to refine prevention strategies for (un)affected individuals.

The Pelvis-First Approach for Robotic Proctectomy in Patients with Redundant Abdominal Colon

BACKGROUND

Robotic surgery is increasingly performed for low rectal cancer.1 A redundant sigmoid colon makes retraction and pelvic dissection challenging. We present a 'pelvis-first' approach to robotic proctectomy where pelvic dissection occurs prior to colonic mobilization.

METHODS

A 26-year-old woman was diagnosed with a clinical T3N1 rectal adenocarcinoma at 3 cm from the anal verge. The patient had Lynch syndrome, with a germline mutation in the PMS2 gene. A near-complete clinical response was observed after neoadjuvant chemoradiation (NCRT), and the patient wished to delay surgery and permanent colostomy. Additional FOLFOX was administered and led to a complete clinical response. After 2.5 months of watchful delay of surgery, the tumor regrew, and the patient then underwent robotic abdominoperineal resection (APR).

RESULTS

Initial exploration revealed a highly redundant sigmoid colon. A pelvis-first approach was undertaken. The colon was left tethered and outside of the pelvis during the pelvic dissection. The levator ani was divided transabdominally. Vascular dissection and left colon mobilization were completed after pelvic dissection.2 The specimen was removed transanally, obviating the need for abdominal incision. An end colostomy was created laparoscopically, and the perineum was closed primarily after omental flap. The patient recovered without complications.

CONCLUSIONS

The 'pelvis-first' approach to proctectomy is advantageous for patients with a highly redundant sigmoid colon. Transabdominal division of the levator ani during APR ensures excellent circumferential margin. Although Lynch syndrome-associated rectal cancer can show excellent response to NCRT,3 patients undergoing watchful delay of surgery require close monitoring and prompt triggering of salvage proctectomy when tumor regrowth is observed.4^,5.

Outcomes of disease-specific next-generation sequencing gene panel testing in adolescents and young adults with colorectal cancer

PURPOSE

Adolescents and young adults with colorectal cancer (CRC) have attracted recent attention, with a hereditary syndrome identified in one-third of patients diagnosed ≤ 35. We aimed to study this population to determine if a CRC-specific gene panel increased the yield of testing.

METHODS

Patients with CRC ≤ 35 evaluated from 05/2014-11/2017 were identified from the genetic counseling database. Records were reviewed for personal/family history and genetic counseling outcomes.

RESULTS

One hundred forty-three patients with CRC ≤ 35 were included. One hundred four (72.7%) underwent CRC panel testing. Thirty-nine (27.2%) had syndrome-directed testing, declined, or were lost to follow-up. Forty-two patients had a genetic syndrome (29.4%). Twenty-four of the 42 hereditary patients (57.1%) were identified via syndrome-directed testing. Mutations identified via panel testing were consistent with patient personal/family history. Thirty-three patients had at least one variant of uncertain significance.

CONCLUSION

Hereditary syndromes were identified in 29.4% of patients. Panel testing in patients without a phenotype did not increase diagnostic yield, but identified variants in one-third. Disease-specific panel testing is of low yield in young patients without a suggestive personal/family history. Testing broader panels may increase the yield of mutation pick-up in this population, although at the expense of identifying variants.

Quality of endoscopy reporting at index colonoscopy significantly impacts outcome of subsequent EMR in patients with > 20 mm colon polyps

Background and study aims  Endoscopic mucosal resection (EMR) is safe and cost-effective in management of patients with colon polyps. However, very little is known about the actions of the referring endoscopist following identification of these lesions at index colonoscopy, and the impact of those actions on the outcome of subsequent referral for EMR. The aim of this study was to identify practices at index colonoscopy that lead to failure of subsequent EMR. Patients and methods  Two hundred and eighty-nine consecutive patients with biopsy-proven non-malignant colon polyps (> 20 mm) referred for EMR were analyzed to identify practices that could be improved from the time of identifying the lesion at index colonoscopy until completion of therapy. Results  EMR was abandoned at colonoscopy at the EMR center in 71 of 289 patients (24.6 %). Reasons for abandoning EMR included diagnosis of invasive carcinoma (n = 9; 12.7 %), tethered lesions (n = 21; 29.6 %) from prior endoscopic interventions, and overly large (n = 22; 31 %) and inaccessible lesions (n = 17; 24 %) for complete and safe resection whose details were not recorded in the referring endoscopy report, or polyposis syndromes (n = 2; 2.8 %) that were not recognized. Conclusions  In our practice, one in four EMR attempts were abandoned as a result of inadequate diagnosis or management by the referring endoscopist, which could be improved by education on optical diagnosis of polyps, comprehensive documentation of the procedure and avoidance of interventions that preclude resection.

Clinical characteristics and outcomes of immune checkpoint inhibitor-induced pancreatic injury

Background

Immune checkpoint inhibitor (ICI)-induced pancreatic injury (ICIPI) is not well documented in the literature. We aimed to describe the clinical characteristics and outcomes of patients who developed ICIPI.

Methods

We reviewed the medical records of consecutive patients who had a confirmed diagnosis of ICIPI (Common Terminology Criteria for Adverse Events grade ≥ 3 lipase elevation with or without clinical symptoms) from April 2011 through April 2018.

Results

Among the 2,279 patients received ICI and had lipase values checked thereafter, 82 (4%) developed ICIPI. Overall, 65% of patients received inhibitors of programmed death protein-1 or its ligand. Compared with asymptomatic presentation, patients who had clinical symptoms of pancreatitis (n = 32) had higher levels of lipase (P = 0.032), more frequent imaging evidence of pancreatitis (P = 0.055), and more frequent hospitalization (P < 0.001) and received intravenous fluids (P < 0.001) and steroids more frequently (P = 0.008). Twelve patients (15%) developed long-term adverse outcomes of ICIPI; three had chronic pancreatitis, four had recurrence of ICIPI, and six had subsequent diabetes. Among 35 patients who resumed ICI therapy, four (11%) had recurrence of lipase elevation. Logistic regression revealed that smoking and hyperlipidemia were associated with increased risk for long-term adverse outcomes of ICIPI, and intravenous fluids were associated with reduced risk. Patients who resumed ICI therapy survived longer than patients who discontinued ICI therapy permanently, statistically not significant (P = 0.0559). Patients who developed long-term adverse outcomes of ICIPI survived significantly longer than those who did not (P = 0.0295). The highest proportion of patients (6/21, 29%) developed long-term adverse outcomes of ICIPI was among those without typical symptoms of pancreatitis, continued ICI therapy after ICIPI, and did not receive intravenous fluids.

Conclusion

ICIPI can present as typical acute pancreatitis, with risk of the development of a pseudocyst, diabetes, and chronic pancreatitis. ICI resumption after ICIPI may lead to recurrence of lipase elevation without increased risk of long-term adverse outcomes, and can increase survival duration. Intravenous fluids may prevent long-term adverse outcomes, but steroids do not appear to affect outcomes of ICIPI. Asymptomatic ICIPI presentation may lead to undertreatment of ICIPI owing to underestimation of its degree, and therefore, intravenous fluid administration could potentially could potentially be benificial to prevent long-term adverse outcomes even in asymptomatic patients.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0502-7) contains supplementary material, which is available to authorized users.

Physical activity and the risk of colorectal cancer in Lynch syndrome

Greater physical activity is associated with a decrease in risk of colorectal cancer for the general population; however, little is known about its relationship with colorectal cancer risk in people with Lynch syndrome, carriers of inherited pathogenic mutations in genes affecting DNA mismatch repair (MMR). We studied a cohort of 2,042 MMR gene mutations carriers (n = 807, diagnosed with colorectal cancer), from the Colon Cancer Family Registry. Self-reported physical activity in three age-periods (20-29, 30-49 and ≥50 years) was summarized as average metabolic equivalent of task hours per week (MET-hr/week) during the age-period of cancer diagnosis or censoring (near-term exposure) and across all age-periods preceding cancer diagnosis or censoring (long-term exposure). Weighted Cox regression was used to estimate the hazard ratio (HR) and 95% confidence intervals (CI) for the association between physical activity and colorectal cancer risk. Near-term physical activity was associated with a small reduction in the risk of colorectal cancer (HR ≥35 vs. <3.5 MET-hr/week, 0.71; 95% CI, 0.53-0.96). The strength and direction of associations were similar for long-term physical activity, although the associations were not nominally significant. Our results suggest that physical activity is inversely associated with the risk of colorectal cancer for people with Lynch syndrome; however, further confirmation is warranted. The potential modifying effect of physical activity on colorectal cancer risk in people with Lynch syndrome could be useful for risk prediction and support counseling advice for lifestyle modification to reduce cancer risk.

Colorectal premalignancy is associated with consensus molecular subtypes 1 and 2

Background

Gene expression-based profiling of colorectal cancer (CRC) can be used to identify four molecularly homogeneous consensus molecular subtype (CMS) groups with unique biologic features. However, its applicability to colorectal premalignant lesions remains unknown.

Patients and methods

We assembled the largest transcriptomic premalignancy dataset by integrating different public and proprietary cohorts of adenomatous and serrated polyps from sporadic (N = 311) and hereditary (N = 78) patient populations and carried out a comprehensive analysis of carcinogenesis pathways using the CMS random forest (RF) classifier.

Results

Overall, transcriptomic subtyping of sporadic and hereditary polyps revealed CMS2 and CMS1 subgroups as the predominant molecular subtypes in premalignancy. Pathway enrichment analysis showed that adenomatous polyps from sporadic or hereditary cases (including Lynch syndrome) displayed a CMS2-like phenotype with WNT and MYC activation, whereas hyperplastic and serrated polyps with CMS1-like phenotype harbored prominent immune activation. Rare adenomas with CMS4-like phenotype showed significant enrichment for stromal signatures along with transforming growth factor-β activation. There was a strong association of CMS1-like polyps with serrated pathology, right-sided anatomic location and BRAF mutations.

Conclusions

Based on our observations made in premalignancy, we propose a model of pathway activation associated with CMS classification in colorectal carcinogenesis. Specifically, while adenomatous polyps are largely CMS2, most hyperplastic and serrated polyps are CMS1 and may transition into other CMS groups during evolution into carcinomas. Our findings shed light on the transcriptional landscape of premalignant colonic polyps and may help guide the development of future biomarkers or preventive treatments for CRC.

Incidence of immune-related adverse events and its association with treatment outcomes: the MD Anderson Cancer Center experience

Background Immunotherapy is emerging as the cornerstone for treatment of patients with advanced cancer, but significant toxicity (immune-related adverse events [irAEs]) associated with unbridled T cell activity remains a concern. Patients and methods A retrospective review of the electronic medical records of 290 patients with advanced cancer treated on an immunotherapy-based clinical trial in the Department of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center between February 2010 and September 2015 was performed. Clinical and laboratory parameters were collected to determine the incidence of irAEs, risk factors, and their association with treatment outcomes. Results Ninety eight of 290 patients (34%) experienced any grade irAEs. Among the 15 (5.2%) patients with grade ≥ 3 irAEs, the most common irAEs were dermatitis and enterocolitis. Although 80% of the patients with grade ≥ 3 irAEs required systemic corticosteroids, all the 15 patients recovered from the irAEs. On re-challenge, 4 of the 5 patients who had received systemic corticosteroids for irAE continued to respond. There were no irAE-related deaths. Importantly, patients with grade ≥ 3 irAEs had improved overall response rate (25 vs. 6%; p = 0.039) and longer median time to progression (30 weeks vs. 10 weeks; p = 0.0040) when compared to those without grade ≥ 3 irAEs. Conclusion Incidence of irAEs with immunotherapeutic agents indicates an active immune status, suggestive of potential clinical benefit to the patient. Further validation of this association in a large prospective study is warranted.

Endoscopic and Histologic Features of Immune Checkpoint Inhibitor-Related Colitis

BACKGROUND

Diarrhea and colitis are the second most common immune checkpoint inhibitor (ICPI)-induced adverse events. However, a comprehensive characterization of the endoscopic and histologic features of ICPI-induced diarrhea and colitis is lacking. Therefore, we aimed to describe endoscopic and histologic features of ICPI-induced gastrointestinal toxicities and to assess their association with patients' clinical characteristics and outcomes.

METHODS

We retrospectively reviewed records of 53 patients with ICPI-related diarrhea/colitis between 2011 and 2017. We collected data on demographics, diarrhea/colitis grade, treatment, and endoscopic and histologic findings. Long-term follow-up included repeat endoscopy findings, diarrhea recurrence, and overall survival. We compared groups by treatment, endoscopic and histologic findings, and constructed Kaplan-Meier survival curves.

RESULTS

Most patients had grade 2 or higher diarrhea (87%) and colitis (60%). Thirty-one patients were successfully treated with corticosteroids, and 22 additionally required infliximab. On endoscopy, 21 (40%) patients had ulcerations and 22 (42%) had nonulcerative inflammation. Patients with ulcerations had more steroid-refractory disease (P = 0.044) and high-grade diarrhea (P = 0.033). Histology showed mostly acute (23%) or chronic (60%) inflammation. During mean follow-up duration of 18.9 months, 19 (36%) developed recurrent diarrhea. Most patients had persistent endoscopic (8/13, 62%) and histologic (9/11, 82%) inflammation. Patients with higher-grade adverse events had improved survival. Higher-grade colitis was associated with endoscopic inflammation (P = 0.039), but grade of diarrhea was not associated with endoscopic inflammation or grade of colitis.

CONCLUSION

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Hepatotoxicity in advanced cancer patients receiving immune-based cancer treatment

67

Background: Immune-based cancer treatment (IBCT) is increasingly used to treat a variety of cancers. Despite the promising results, adverse events such as dermatitis, colitis, and hepatitis remain a concern. Hepatitis is usually mild but may be severe, requiring modification or cessation of treatment. Here, we describe several cases of immune-mediated hepatitis. Methods: We identified patients enrolled in clinical trials using IBCT through the Department of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center, between January 2010 and July 2015. Charts were reviewed for mention of “autoimmune hepatitis”, “hepatitis” or abnormal transaminases, all of which were attributed to IBCT by the treating physician. Hepatotoxicity was graded based on CTCAE v4.0. Results: We identified 12 cases of immune-related hepatotoxicity out of 290 patients. Three patients (1.03%) had grade 3 elevation of transaminases, designated as “autoimmune hepatitis.” Each required systemic steroids and transaminases returned to baseline within a month. IBCT was temporarily held in 2 cases and was permanently discontinued in the third due to grade 4 myositis rather than hepatitis. One patient (0.3%) had grade 2, and eight patients (2.8%) had grade 1 transaminases elevations that were possibly attributable to immunotherapy, but which resolved spontaneously without alteration in treatment. Other significant reported immune-related toxicities ≥ grade 3 were: dermatitis (n = 4), enterocolitis (n = 3), myasthenia gravis (n = 2), myositis (n = 2), pneumonitis, pleuritis, and pancreatitis (n = 1 each). Conclusions: 1.03% of patients experienced grade 3 elevation of transaminases that were attributable to immune therapy. Hepatic adverse events related to immunotherapy in our study were manageable. Further studies are needed to develop biomarkers to identify patients at risk to develop such toxicities. [Table: see text]

Does deep sedation with propofol affect adenoma detection rates in average risk screening colonoscopy exams?

AIM

To determine the effect of sedation with propofol on adenoma detection rate (ADR) and cecal intubation rates (CIR) in average risk screening colonoscopies compared to moderate sedation.

METHODS

We conducted a retrospective chart review of 2604 first-time average risk screening colonoscopies performed at MD Anderson Cancer Center from 2010-2013. ADR and CIR were calculated in each sedation group. Multivariable regression analysis was performed to adjust for potential confounders of age and body mass index (BMI).

RESULTS

One-third of the exams were done with propofol (n = 874). Overall ADR in the propofol group was significantly higher than moderate sedation (46.3% vs 41.2%, P = 0.01). After adjustment for age and BMI differences, ADR was similar between the groups. CIR was 99% for all exams. The mean cecal insertion time was shorter among propofol patients (6.9 min vs 8.2 min; P < 0.0001).

CONCLUSION

Deep sedation with propofol for screening colonoscopy did not significantly improve ADR or CIR in our population of average risk patients. While propofol may allow for safer sedation in certain patients (e.g., with sleep apnea), the overall effect on colonoscopy quality metrics is not significant. Given its increased cost, propofol should be used judiciously and without the implicit expectation of a higher quality screening exam.

B-Cell Lymphoma Patient-Derived Xenograft Models Enable Drug Discovery and Are a Platform for Personalized Therapy

Purpose: Patients with B-cell lymphomas often relapse after frontline therapy, and novel therapies are urgently needed to provide long-term remission. We established B-cell lymphoma patient-derived xenograft (PDX) models to assess their ability to mimic tumor biology and to identify B-cell lymphoma patient treatment options.Experimental Design: We established the PDX models from 16 patients with diffuse large B-cell lymphoma, mantle cell lymphoma, follicular lymphoma, marginal zone lymphoma, or Burkitt lymphoma by inoculating the patient tumor cells into a human bone chip implanted into mice. We subjected the PDX models to histopathologic and phenotypical examination, sequencing, and drug efficacy analysis. Primary and acquired resistance to ibrutinib, an oral covalent inhibitor of Bruton tyrosine kinase, were investigated to elucidate the mechanisms underlying ibrutinib resistance and to identify drug treatments to overcome resistance.Results: The PDXs maintained the same biological, histopathologic, and immunophenotypical features, retained similar genetic mutations, and produced comparable drug responses with the original patient tumors. In the acquired ibrutinib-resistant PDXs, PLC-γ2, p65, and Src were downregulated; however, a PI3K signaling pathway member was upregulated. Inactivation of the PI3K pathway with the inhibitor idelalisib in combination with ibrutinib significantly inhibited the growth of the ibrutinib-resistant tumors. Furthermore, we used a PDX model derived from a clinically ibrutinib-relapsed patient to evaluate various therapeutic choices, ultimately eliminating the tumor cells in the patient's peripheral blood.Conclusions: Our results demonstrate that the B-cell lymphoma PDX model is an effective system to predict and personalize therapies and address therapeutic resistance in B-cell lymphoma patients. Clin Cancer Res; 23(15); 4212-23. ©2017 AACR.

Outcome of EMR as an alternative to surgery in patients with complex colon polyps

BACKGROUND AND AIMS

Patients with complex colon polyps were traditionally referred for surgery to avoid adverse events associated with endoscopic resection. Recent advances in endoscopic imaging as well as endoscopic hemostasis and clip closure allow for the use of EMR as an alternative to surgery for such lesions. To determine the outcome of treatment of complex colon polyps with EMR as an alternative to surgery, we conducted a retrospective observational study.

METHODS

Two hundred three patients with complex colon polyps were referred to an EMR center as an alternative to surgery. Patients underwent a protocol-driven EMR. The primary endpoint was the complete resection rate. Secondary endpoints were safety, residual adenoma rate, and incidence of missed synchronous polyps.

RESULTS

EMR was performed in 155 patients and was deferred in 48 patients who were referred to surgery. EMR specimens revealed benign polyps in 149 and cancer in 6 patients. EMR adverse events occurred in 7 patients, requiring hospitalization in 5 of them. None of the patients died as a result of their adverse events. Surveillance colonoscopy at 4 to 6 months after resection of a benign lesion in 137 patients revealed residual adenoma at the scar site in 6 patients and additional synchronous precancerous lesions in 117 patients that were not removed by the referring endoscopist. None underwent surgery for failure of EMR. The overall precancerous lesion burden was 2.83 per patient, the adenoma burden was 2.13 per patient, and the serrated polyp burden was .69 per patient.

CONCLUSIONS

EMR can be used instead of surgery for complex colon polyps in 75% of patients with few adverse events and few residual adenomas at resection sites. In addition, careful repeat examination of the entire colon for synchronous lesions overlooked by the referring endoscopist is required for most patients. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01827241.).

Can Technology Improve the Quality of Colonoscopy?

In order for screening colonoscopy to be an effective tool in reducing colon cancer incidence, exams must be performed in a high-quality manner. Quality metrics have been presented by gastroenterology societies and now include higher adenoma detection rate targets than in the past. In many cases, the quality of colonoscopy can often be improved with simple low-cost interventions such as improved procedure technique, implementing split-dose bowel prep, and monitoring individuals' performances. Emerging technology has expanded our field of view and image quality during colonoscopy. We will critically review several technological advances in the context of quality metrics and discuss if technology can really improve the quality of colonoscopy.

Abstract 67: Genomic and mutational profiling of human colon adenomas reveals early driver mutations and a TGF-β-CEA regulated profile

Introduction: Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the world with 143,700 newly diagnosed cases in 2012. The rapid development of cancers in small, sessile adenomas could be a contributing factor that may have been overlooked. Identifying high risk patients through genomic analysis of adenomas could potentially lead to an early intervention therapy.

Methods: Whole Genome Sequence (WGS) and Whole Exome Sequence (WES) analyses were performed for 4 pairs of normal controls (two from proximal colon and two from the distal colon) and colorectal adenomas (2 sessile serrated (SSA) and 2 tubulovillous adenomas (TVA) less than 1 cm in size). Transcriptome sequence analysis was performed in seven pairs of control-test matched adenomas (6 TVA and 1 SSA). Expression level of CEA and TGF-β pathway members were carried out on 30 non dysplastic adenomas and normal colon tissues by immunohistochemistry.

Results: 1. Hyper-mutator profiles were observed in two of the samples (1 SSA and 1 TVA) by WGS with 1709 mutations after normalization with normal paired samples. 2. The samples showed an average mutation frequency of 0.55 mutations per 106 bases. 3. Aberrant mutational profiles was detected in seven of the eleven adenomas, with distinct mutational signatures among the samples, two with high, two intermediate and three low mutational rates. 4. Six of the eleven adenomas (1 SSA and 4 TVAs) showed alteration in the Wnt and p53 pathway. 5. Transitional single nucleotide substitutions of C:T&gt;G:A in the mutational spectrum were observed in 37% of the samples. 6. Subtle localized hyper mutation (kataegis) was observed among two of the samples. 7. Five out of eleven adenomas showed mutations in the TGF-β (transforming growth factor-β) and CEA pathways members, overlapping with Wnt/p53 mutations in four adenomas. 8. Analyses of expression level of CEA and TGF-β pathway members in 30 non dysplastic tissues revealed a marked increase (over 8 fold) in CEA expression in 25% of adenoma samples which was linked to concomitant loss of TGF-β signaling. 9. Further functional studies revealed that CEA associated with TGF-β Type I receptor and disruption of TGF-β tumor suppressor signaling with activation of STAT3.

Conclusions: Our studies indicate that small adenomas both TVAs and SSAs can resemble CRCs in genomic profiling and may reflect a high risk population. Genetic and mechanistic analyses reveal that disruption of CEA/TGF-β pathway in early adenomas may reflect a new and early role for these pathways in CRC. This study further supports the biomarker driven targeting of CEA/TGF-β in high risk adenomas and can be used as a prognostic marker for early detection of aggressive adenoma-CRC progression.

Citation Format: Vipin K. Menon, Raju S. Gottumukkala, Jian Chen, Xiaoping Su, Nipun Mistry, Avijit Majumdar, Ji-Hyun Shin, Shulin Li, Kirti Shetty, Xifeng Wu, Brian Weston, Ethan Miller, John R. Stroehlein, Marta L. Davila, Mehnaz A. Shafi, Asif Rashid, Bhaskar V. Kallakury, Selvi Thirumurthi, John S. McMurray, Sue-Hwa Lin, Wilma Jogunoori, Lopa Mishra. Genomic and mutational profiling of human colon adenomas reveals early driver mutations and a TGF-β-CEA regulated profile. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 67. doi:10.1158/1538-7445.AM2015-67

Management of polypectomy complications

The 2 most significant complications of colonoscopy with polypectomy are bleeding and perforation. Incidence rates for bleeding (0.1%-0.6%) and perforation (0.7%-0.9%) are generally low. Recognition of pertinent risk factors helps to prevent these complications, which can be grouped into patient-related, polyp-related, and technique/device-related factors. Endoscopists should be equipped to manage bleeding and perforation. Currently available devices and techniques are reviewed to achieve hemostasis and close colon perforations.

Safety of endoscopic interventions in patients with thrombocytopenia

BACKGROUND

The risk of endoscopic interventions in thrombocytopenia has received little attention in the medical literature.

OBJECTIVE

The aim of this study was to assess the safety of endoscopic interventions including evaluation of GI bleeding (GIB) in patients with thrombocytopenia.

DESIGN AND SETTING

Retrospective study, tertiary oncology center.

PATIENTS AND INTERVENTION

Review of consecutive endoscopies with preprocedure platelet counts (PCs) of 75 × 10(3)/μL or lower.

MAIN OUTCOME MEASUREMENTS

Risk of bleeding with routine endoscopic interventions and transfusion requirement after evaluation of GIB.

RESULTS

A total of 617 (351 upper, 266 lower [90 colonoscopies]) endoscopies were performed in 395 patients. Forceps-biopsy specimens were obtained in 398 endoscopies (mean ± standard deviation [SD] PC: 38.21 ± 11.7 × 10(3)/μL) and 45 polypectomies were performed in 17 endoscopies (mean ± SD PC: 39.65 ± 8.53 × 10(3)/μL). The risk of bleeding was 1.5% (6 of 398 endoscopies) at the biopsy site and 4% (2 of 45 polypectomies) at the polypectomy site. Active GIB (mean ± SD PC: 32.85 ± 4.0 × 10(3)/μL) was observed in 68 (11% of 617) endoscopies and intervention (mean ± SD PC: 33.68 ± 4.6 × 10(3)/μL) was performed in 41 procedures. Together, angiodysplasias and ulcers were the most common etiology (51.2% of 41). Hemostasis was achieved in 39 (95.1% of 41) procedures. Comparison of blood transfusions ± 3 days of successful therapy showed a 52% reduction (P < .001). By multivariate analysis, a higher aggregate blood transfusion 3 days preceding endoscopy (odds ratio 1.32; 95% confidence interval, 1.16-1.50; P < .001) predicted endoscopic findings of active GIB.

LIMITATIONS

Retrospective design, single center.

CONCLUSIONS

In the largest endoscopic experience reported in thrombocytopenic patients (Common Terminology Criteria for Adverse Events grade 3 or lower), bleeding caused by standard forceps biopsy and polypectomy (≤10 mm) was minor and easily controlled. Endoscopic therapy for GIB is safe and significantly reduces the packed red blood cell requirement and should be considered in patients with thrombocytopenia in the setting of an appropriate transfusion strategy.

Radiation exposure from diagnostic imaging studies among patients with inflammatory bowel disease in a safety-net health-care system

BACKGROUND/AIMS

Radiographic imaging studies are important in the management of patients with inflammatory bowel disease (IBD), but are associated with radiation exposure. IBD patients in a safety-net health-care system may be at risk of high exposure to radiation. Our purpose was to identify associations of high-dose radiation exposure among an ethnically diverse cohort of IBD patients in a safety-net health-care system.

METHODS

A study was performed on patients with IBD receiving care from the Harris County Hospital District. Radiation exposure was calculated using total number of imaging studies performed between from 2000 and 2010 and estimates of radiation dose per study. Associations of high-dose radiation exposure, defined as a cumulative effective dose (CED) >50 mSv, were identified by using univariate and multivariate logistic regression.

RESULTS

The study cohort of 278 patients with IBD was ethnically diverse, with 30 % Caucasian, 44 % African-American, and 26 % Hispanic. The median CED was 10.40 mSv (SD 20.02). Annualized radiation doses were 3.45 mSv/year among patients with Crohn's disease (CD) and 1.27 mSv/year among patients with ulcerative colitis, p < 0.02. Approximately 13 % of IBD patients received a CED >50 mSv. There were no differences in radiation exposure based on age, gender, or race/ethnicity.

CONCLUSIONS

A small proportion of IBD patients in a safety-net health-care system received high doses of diagnostic radiation exposure. Use of diagnostic imaging studies that limit radiation exposure should be encouraged.

Detection of clarithromycin resistance in Helicobacter pylori following noncryogenic storage of rapid urease tests for 30 days

OBJECTIVE

Traditional Helicobacter pylori (H. pylori) eradication therapy has been undermined by increasing antimicrobial, especially clarithromycin, resistance. Susceptibility testing in some areas is difficult to achieve or unavailable. We aimed to determine whether gastric biopsy specimens stored at room temperature for rapid urease test (RUT) were suitable for clarithromycin susceptibility testing of H. pylori.

METHODS

After 30 days of storage at room temperature, DNA was extracted from gastric biopsies present in RUTs (Hpfast). H. pylori status and clarithromycin susceptibility were evaluated using H. pylori-specific polymerase chain reaction (PCR) for ureA, vacA, and allele-specific primer-PCR of the 23S rRNA genes. The PCR results were compared with histology, RUT, and culture results. H. pylori positive was defined as RUT and either culture or histology positive; H. pylori negative as RUT, culture and histology negative.

RESULTS

Samples from 31 patients were evaluated; 11 were H. pylori positive including 9 by culture; seven of which had allele-specific primer-PCR results from the RUT specimen for the detection of mutations of the 23S rRNA gene. When both tests were available, culture and PCR results were concordant in 7 cases. In 15 of the 20 histology, RUT and culture negative patients, three PCR were negative. In one patient, all of the three tests were positive; and in three only the 23S rRNA was positive and in one only ureA was positive.

CONCLUSION

Gastric biopsy specimens stored in the gel of RUT for 30 days can be used for molecular testing to confirm the diagnosis of H. pylori infection and test for clarithromycin susceptibility.

Epidemiology of inflammatory bowel disease among an indigent multi-ethnic population in the United States

BACKGROUND

Environmental factors, including socioeconomic status, may affect inflammatory bowel disease (IBD). There is a paucity of data on the epidemiology of IBD among patients of low socioeconomic status.

AIM

To examine the epidemiologic features of IBD among African-American, Hispanic, and Caucasian patients from a county hospital, where the majority of the patients are socioeconomically disadvantaged.

METHODS

A retrospective study was conducted on a cohort of patients diagnosed with IBD based on clinical, radiologic, endoscopic, and histological data. We reviewed charts of adults aged 20-70 years diagnosed with IBD between 2000 and 2006. Demographic data, disease subtype, and phenotypic features of IBD were recorded based on the Montreal Classification. The data were analyzed using the chi-square, Fisher exact, Wilcoxon rank-sum, and Student's t-tests.

RESULTS

The study cohort included 273 patients, with 54% female, 30% Caucasian, 44% African-American, and 26% Hispanic. Over half (54%) of the patients had Crohn's disease (CD), and 46% had ulcerative colitis (UC). The mean age at diagnosis was 40 ± 14 years with no significant difference between CD and UC (age 43 ± 13 versus 44.5 ± 14, respectively; P = 0.5). Females were diagnosed at a significantly later age than males (46 ± 13 years versus 40 ± 13, respectively; P = 0.001). This trend remained significant for females with CD and UC, and across each racial/ethnic group. Hispanic patients were diagnosed with UC more often than Caucasian patients (64% versus 34%; odds ratio [OR] 3.5; 95% confidence interval [CI]: 1.8-6.5, P = 0.0003) or African-Americans (64% versus 43%; OR 2.3; 95% CI: 1.3-4.3, P = 0.005). Among the 147 patients with CD, 54% had fistulizing and/or stricturing disease. The prevalence of fistulizing, stricturing, and inflammatory CD was similar across all age, gender, and racial/ethnic groups.

CONCLUSIONS

Within an indigent population, UC was diagnosed more often in Hispanics than CD. Females were diagnosed at a significantly older age than males across all racial/ethnic groups. There was no difference in the CD phenotypes between the three ethnic groups. Understanding the epidemiology of IBD will require examination of the interactions between gender, race/ethnicity, and environmental factors.

Helicobacter pylori infection in India from a western perspective

Helicobacter pylori is a common bacterial infectious disease whose manifestations predominately affect the gastrointestinal tract. India is the prototypical developing country as far as H. pylori infection is concerned and more than 20 million Indians are estimated to suffer from peptic ulcer disease. Considering the high level of Medicine and of the pharmaceutical industry, one would expect that India would be the source of much needed information regarding new therapies and approaches that remain effective in the presence of antimicrobial resistance, new methods to reliably prevent reinfection, and the development of therapeutic and preventive vaccines. Here, we discuss H. pylori as an Indian problem with an emphasis on H. pylori infection as a serious transmissible infectious disease. We discuss the pros and cons of eradication of H. pylori from the entire population and come down on the side of eradication. The available data from India regarding antimicrobial use and resistance as well as the effectiveness of various treatments is discussed. Rigorous ongoing studies to provide current regional antibiotic resistance patterns coupled with data concerning the success rate with different treatment regimens are needed to guide therapy. A systematic approach to identify reliably effective (e.g., 90% or greater treatment success) cost-effective regimens is suggested as well as details of regimens likely to be effective in India. H. pylori is just one of the health care problems faced in India, but one where all the resources are on hand to understand and solve it.

Validation of ICD-9-CM diagnostic codes for inflammatory bowel disease among veterans

BACKGROUND

Inflammatory bowel disease (IBD) is well described among young whites and less so among the elderly and non-whites. Population-level data is required to assess outcomes among minority groups.

AIM

To validate diagnostic codes for IBD from the Department of Veterans Affairs.

METHODS

National databases were used to identify local patients with Crohn's disease (CD) and ulcerative colitis (UC), the extra-intestinal manifestations and surgical procedures associated with IBD. Diagnosis was confirmed by manual chart abstraction. Multivariable logistic regression was used to derive diagnostic algorithms for CD and UC, which were then validated in an independent cohort.

RESULTS

The test cohort of 3,827 patients (1,316 potential cases, 2,511 random controls) was predominantly male (94%), white (56%), and of age of 58 (standard deviation 15). The positive predictive value (PPV) of CD codes was superior (88-100%) to UC (50-93%). The accuracy of extra-intestinal manifestations and surgeries was poor (PPV 0-29%). ICD-9-CM code 555.x without 560.9 had a PPV of 91% for CD in the validation cohort. Code 556.x with age, gender, and race factors was highly predictive of UC (c-statistic 0.9, PPV of 81%).

CONCLUSION

VA administrative data can diagnose elderly and non-white patients with IBD.

Identification of Helicobacter pylori infected patients, using administrative data

BACKGROUND

Helicobacter pylori is a prevalent organism implicated in peptic ulcer disease.

AIM

To validate administrative data for diagnosis of H. pylori-infected patients.

METHODS

Administrative data identified patients with ICD-9 code for H. pylori (041.86) or prescription of eradication therapy; diagnosis was confirmed by chart abstraction. Multivariable regression assessed predictors of infection considering drug therapy, ICD-9 code 041.86, procedure code, in-patient or out-patient diagnostic code, age, gender and race to generate an algorithm for validation.

RESULTS

The test cohort of 531 patients (361 potential cases; 170 random controls) was primarily male (94%), Caucasian (59%) and elderly [67 years (s.d. 10)]. The positive predictive value (PPV) of ICD-9 code 041.86 was 100% and 97.4% if from an in-patient or out-patient encounter, respectively. Eradication drug therapy had a PPV of 73.7% (triple therapy) and 97.7% (quadruple therapy). The strongest predictors were out-patient ICD-9 code 041.86 (OR 8.1; 95% CI: 7.0-9.1); eradication drug therapy (OR 7.4; 95% CI: 6.6-8.3); oesophagogastroduodenoscopy (OR 3.5; 95% CI: 3.3-3.6); and age > or =70 (OR 1.2; 95% CI: 1.1-1.4). An algorithm including these data elements yielded a c-statistic of 0.93 and PPV of 97.9%.

CONCLUSIONS

Administrative data can diagnose H. pylori-infected patients. The diagnostic algorithm includes presence of eradication drug therapy overlapping with an out-patient ICD-9 code 041.86 among elderly adults.