Primary Care Telehealth Visits and Its Association with Provider Discussion on Colorectal Cancer Screening in the United States

Background: Provider discussions about colorectal cancer (CRC) screening are the single most important predictor for CRC screening uptake. Methods: Using cross-sectional data from the 2022 Health Information National Trends Survey, we evaluated the relationship between telehealth use and provider discussion about CRC screening with a multivariable logistic regression model. Results: Of adults aged 45-75 years, 20.3% used telehealth services in the past year of which 69.5% had discussed CRC screening with their providers. There was no difference in provider discussion about CRC screening between telehealth users and nonusers (OR 1.26; 95% confidence interval 0.83-1.90). Conclusion: Telehealth is an important adjunct in health care delivery, enhancing patient-provider discussions about CRC screening.

Evaluation of EGFR and COX pathway inhibition in human colon organoids of serrated polyposis and other hereditary cancer syndromes

Serrated polyposis syndrome (SPS) presents with multiple sessile serrated lesions (SSL) in the large intestine and confers increased colorectal cancer (CRC) risk. However, the etiology of SPS is not known. SSL-derived organoids have not been previously studied but may help provide insights into SPS pathogenesis and identify novel biomarkers and chemopreventive strategies. This study examined effects of EGFR and COX pathway inhibition in organoid cultures derived from uninvolved colon and polyps of SPS patients. We also compared with organoids representing the hereditary gastrointestinal syndromes, Familial Adenomatous Polyposis (FAP) and Lynch syndrome (LS). Eighteen total organoid colon cultures were generated from uninvolved colon and polyps in SPS, FAP, LS, and non-syndromic screening colonoscopy patients. BRAF and KRAS mutation status was determined for each culture. Erlotinib (EGFR inhibitor) and sulindac (COX inhibitor) were applied individually and in combination. A 44-target gene custom mRNA panel (including WNT and COX pathway genes) and a 798-gene microRNA gene panel were used to quantitate organoid RNA expression by NanoString analysis. Erlotinib treatment significantly decreased levels of mRNAs associated with WNT and MAPK kinase signaling in organoids from uninvolved colon from all four patient categories and from all SSL and adenomatous polyps. Sulindac did not change the mRNA profile in any culture. Our findings suggest that EGFR inhibitors may contribute to the chemopreventive treatment of SSLs. These findings may also facilitate clinical trial design using these agents in SPS patients. Differentially expressed genes identified in our study (MYC, FOSL1, EGR1, IL33, LGR5 and FOXQ1) may be used to identify other new molecular targets for chemoprevention of SSLs.

Awareness of the causal association between human papillomavirus and anal cancer among US adults

PURPOSE

The incidence of anal cancer is on the rise in the US, especially among high-risk groups. This study examined the prevalence and determinants of awareness of the causal relationship between HPV and anal cancer among US adults.

METHODS

Study data was obtained from the 2017 to 2020 iterations of the Health Information National Trends Survey. The prevalence of awareness that HPV causes anal cancer was estimated among HINTS respondents who were aware of HPV in general. Survey weights were used to provide estimates representative of the adult US population. Multivariable logistic regressions were used to examine the associations between awareness that HPV causes anal cancer and cancer-related behaviors/perceptions and sociodemographic characteristics of respondents.

RESULTS

Two thousand six hundred and eighty four (27.2%) of the study population were aware that HPV caused anal cancer. Those of gay sexual orientation were more aware than heterosexuals [OR 2.27; 95% CI (1.24, 4.14)]. Compared to respondents with a high school diploma or less, individuals with some college education [OR 1.38; 95% CI (1.03, 1.85)] and those with at least a college degree [OR 1.52; 95% CI (1.17, 1.98)] were more likely to be aware. Participants who had positive cancer information seeking behavior were more aware of the HPV-anal cancer link compared to those who did not [OR 1.57; 95% CI (1.30, 1.89)].

CONCLUSION

Population-level awareness that HPV causes anal cancer remains critically low in the US. Sexual orientation, level of education and cancer information seeking behavior are associated with increased awareness of the causal relationship between HPV and anal cancer. Efforts should be directed toward addressing the awareness gap among individuals with lower education levels and promoting curiosity-driven information seeking behaviors.

Applicability of Online Chat-Based Artificial Intelligence Models to Colorectal Cancer Screening

BACKGROUND

Over the past year, studies have shown potential in the applicability of ChatGPT in various medical specialties including cardiology and oncology. However, the application of ChatGPT and other online chat-based AI models to patient education and patient-physician communication on colorectal cancer screening has not been critically evaluated which is what we aimed to do in this study.

METHODS

We posed 15 questions on important colorectal cancer screening concepts and 5 common questions asked by patients to the 3 most commonly used freely available artificial intelligence (AI) models. The responses provided by the AI models were graded for appropriateness and reliability using American College of Gastroenterology guidelines. The responses to each question provided by an AI model were graded as reliably appropriate (RA), reliably inappropriate (RI) and unreliable. Grader assessments were validated by the joint probability of agreement for two raters.

RESULTS

ChatGPT and YouChat™ provided RA responses to the questions posed more often than BingChat. There were two questions that > 1 AI model provided unreliable responses to. ChatGPT did not provide references. BingChat misinterpreted some of the information it referenced. The age of CRC screening provided by YouChat™ was not consistently up-to-date. Inter-rater reliability for 2 raters was 89.2%.

CONCLUSION

Most responses provided by AI models on CRC screening were appropriate. Some limitations exist in their ability to correctly interpret medical literature and provide updated information in answering queries. Patients should consult their physicians for context on the recommendations made by these AI models.

Exploring Stakeholders' Perspectives on Implementing Universal Germline Testing for Colorectal Cancer: Findings From a Clinical Practice Survey

PURPOSE

New guidelines recommend considering germline genetic testing for all patients with colorectal cancer (CRC). However, there is a lack of data on stakeholders' perspectives on the advantages and barriers of implementing universal germline testing (UGT). This study assessed the perspectives of members of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer (CGA-IGC) regarding the implementation of UGT for patients with CRC, including readiness, logistics, and barriers.

METHODS

A cross-sectional survey was sent to 317 active members of CGA-IGC. The survey included sections on demographics, clinical practice specialty, established institutional practices for testing, and questions pertaining to support of and barriers to implementing UGT for patients with CRC.

RESULTS

Eighty CGA-IGC members (25%) participated, including 42 genetic counselors (53%) and 14 gastroenterologists (18%). Forty-seven (59%) reported an academic medical center as their primary work setting, and most participants (56%) had more than 10 years of clinical practice. Although most participants (73%) supported UGT, 54% indicated that changes in practice would be required before adopting UGT, and 39% indicated that these changes would be challenging to implement. There was support for both genetics and nongenetics providers to order genetic testing, and a majority (57%) supported a standardized multigene panel rather than a customized gene panel. Key barriers to UGT implementation included limited genetics knowledge among nongenetics providers, time-consuming processes for obtaining consent, ordering tests, disclosing results, and lack of insurance coverage.

CONCLUSION

This study demonstrates wide support among hereditary GI cancer experts for implementation of UGT for patients with CRC. However, alternative service delivery models using nongenetics providers should be considered to address the logistical barriers to UGT implementation, particularly the growing demand for genetic testing.

Current chemoprevention approaches in Lynch syndrome and Familial adenomatous polyposis: a global clinical practice survey

Background

International chemoprevention preferences and approaches in Lynch syndrome (LS) and APC-associated polyposis, including Familial adenomatous polyposis (FAP) and attenuated FAP (AFAP) have not been previously explored.

Aim

To describe current chemoprevention strategies for patients with LS or FAP/AFAP (referred to collectively as FAP) practiced by members of four international hereditary cancer societies through administration of a survey.

Results

Ninety-six participants across four hereditary gastrointestinal cancer societies responded to the survey. Most respondents (91%, 87/96) completed information regarding their demographics and practice characteristics relating to hereditary gastrointestinal cancer and chemoprevention clinical practices. Sixty-nine percent (60/87) of respondents offer chemoprevention for FAP and/or LS as a part of their practice. Of the 75% (72/96) of survey respondents who were eligible to answer practice-based clinical vignettes based off of their responses to ten barrier questions regarding chemoprevention, 88% (63/72) of those participants completed at least one case vignette question to further characterize chemoprevention practices in FAP and/or LS. In FAP, 51% (32/63) would offer chemoprevention for rectal polyposis, with sulindac - 300 mg (18%, 10/56) and aspirin (16%, 9/56) being the most frequently selected options. In LS, 93% (55/59) of professionals discuss chemoprevention and 59% (35/59) frequently recommend chemoprevention. Close to half of the respondents (47%, 26/55) would recommend beginning aspirin at time of commencement of the patient's first screening colonoscopy (usually at age 25yrs). Ninety-four percent (47/50) of respondents would consider a patient's diagnosis of LS as an influential factor for aspirin use. There was no consensus on the dose of aspirin (≤100 mg, >100 mg - 325 mg or 600 mg) to offer patients with LS and there was no agreement on how other factors, such as BMI, hypertension, family history of colorectal cancer, and family history of heart disease, would affect the recommendation for aspirin use. Possible harm among older patients (>70 years) was identified as the most common reason to discourage aspirin use.

Conclusion

Although chemoprevention is widely discussed and offered to patients with FAP and LS by an international group of hereditary gastrointestinal cancer experts, there is significant heterogeneity in how it is applied in clinical practice.

Three Pathologic Criteria for Reproducible Diagnosis of Colonic Sessile Serrated Lesion Versus Hyperplastic Polyp

BACKGROUND

Colonic sessile serrated lesions are thought to predispose to ∼30% of colonic adenocarcinomas. This increased risk, compared to benign hyperplastic polyps, makes their distinction vitally important. However, no gold standard exists to differentiate them, and wide observer variability is reported.

METHODS

To better distinguish these polyps, we investigated 94 serrated polyps (53 sessile serrated lesions and 41 hyperplastic polyps), using an easy-to-apply pathologic scoring system that combines, for the first time, three established distinguishing features: polyp morphology, location, and size. As an additional novel approach, polyp size was assessed by serrated biopsy number compared to endoscopic size. RNA expression profiling served as an additional biomarker. The considerable morphologic overlap across serrated polyps was quantitated for the first time. Interobserver variability was assessed by eight expert gastrointestinal pathologists.

RESULTS

By ROC analysis, polyp size by biopsy number performed best, followed by polyp location and morphology (areas under the curves [AUC] 85.9%, 81.2%, 65.9%, respectively). Optimal discrimination combined all three features (AUC 92.9%). For polyp size, biopsy number proved superior to endoscopic size (AUC 85.9% versus 55.2%, p=0.001). Interobserver variability analysis yielded the highest reported Fleiss and Kappa statistics (0.879) and percent agreement (96.8%), showing great promise toward improved diagnosis.

CONCLUSIONS

The proposed three-criteria pathologic system, combining size by biopsy number, location, and morphology, yields an improved, easy to use, and highly reproducible diagnostic approach for differentiating sessile serrated lesions and hyperplastic polyps.

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.

Patterns of germline and somatic testing after universal tumor screening for Lynch syndrome: A clinical practice survey of active members of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer

Clinical guidelines recommend universal tumor screening (UTS) of colorectal and endometrial cancers for Lynch syndrome (LS). There are limited guidelines for how to integrate germline testing and somatic tumor testing after a mismatch repair deficient (dMMR) tumor is identified. We sought to characterize current practice patterns and barriers to preferred practice among clinical providers in high‐risk cancer programs. A clinical practice survey was sent to 423 active members of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer (CGA‐IGC) with a follow‐up survey sent to 103 clinician responders. The survey outlined clinical vignettes and asked respondents their preferred next test. The survey intended to assess: (1) the role of patient age and family history in risk assessment and (2) barriers to preferred genetic testing. Genetic test options included targeted germline testing based on dMMR expression, germline testing for LS, germline testing with a multigene cancer panel including LS, or paired tumor/germline testing including LS. In October 2020, 117 of 423 (28%) members completed the initial survey including 103 (88%) currently active clinicians. In April 2021, a follow‐up survey was sent to active clinicians, with 45 (44%) completing this second survey. After selecting their preferred next germline or paired tumor/germline tumor test based on the clinical vignette, 39% of respondents reported wanting to make a different choice for the initial genetic test without any testing barriers. The proportion of respondents choosing a different initial genetic test was dependent on the proband's age at diagnosis and specified family history. The reported barriers included patient's lack of insurance coverage, patient unable/unwilling to self‐pay for proposed testing, and inadequate tumor tissue. Responders reported insurance, financial constraints, and limited tumor tissue as influencing preferred genetic testing in high‐risk clinics, thus resulting in possible under‐diagnosis of LS and impacting potential surveillance and cascade testing of at‐risk relatives.

NCCN Guidelines® Insights: Genetic/Familial High-Risk Assessment: Colorectal, Version 1.2021

Identifying individuals with hereditary syndromes allows for timely cancer surveillance, opportunities for risk reduction, and syndrome-specific management. Establishing criteria for hereditary cancer risk assessment allows for the identification of individuals who are carriers of pathogenic genetic variants. The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal provides recommendations for the assessment and management of patients at risk for or diagnosed with high-risk colorectal cancer syndromes. The NCCN Genetic/Familial High-Risk Assessment: Colorectal panel meets annually to evaluate and update their recommendations based on their clinical expertise and new scientific data. These NCCN Guidelines Insights focus on familial adenomatous polyposis (FAP)/attenuated familial adenomatous polyposis (AFAP) syndrome and considerations for management of duodenal neoplasia.

Screening and prevention of colorectal cancer

Mortality from colorectal cancer is reduced through screening and early detection; moreover, removal of neoplastic lesions can reduce cancer incidence. While understanding of the risk factors, pathogenesis, and precursor lesions of colorectal cancer has advanced, the cause of the recent increase in cancer among young adults is largely unknown. Multiple invasive, semi- and non-invasive screening modalities have emerged over the past decade. The current emphasis on quality of colonoscopy has improved the effectiveness of screening and prevention, and the role of new technologies in detection of neoplasia, such as artificial intelligence, is rapidly emerging. The overall screening rates in the US, however, are suboptimal, and few interventions have been shown to increase screening uptake. This review provides an overview of colorectal cancer, the current status of screening efforts, and the tools available to reduce mortality from colorectal cancer.

Naproxen chemoprevention promotes immune activation in Lynch syndrome colorectal mucosa

OBJECTIVE

Patients with Lynch syndrome (LS) are at markedly increased risk for colorectal cancer. It is being increasingly recognised that the immune system plays an essential role in LS tumour development, thus making an ideal target for cancer prevention. Our objective was to evaluate the safety, assess the activity and discover novel molecular pathways involved in the activity of naproxen as primary and secondary chemoprevention in patients with LS.

DESIGN

We conducted a Phase Ib, placebo-controlled, randomised clinical trial of two dose levels of naproxen sodium (440 and 220 mg) administered daily for 6 months to 80 participants with LS, and a co-clinical trial using a genetically engineered mouse model of LS and patient-derived organoids (PDOs).

RESULTS

Overall, the total number of adverse events was not different across treatment arms with excellent tolerance of the intervention. The level of prostaglandin E2 in the colorectal mucosa was significantly decreased after treatment with naproxen when compared with placebo. Naproxen activated different resident immune cell types without any increase in lymphoid cellularity, and changed the expression patterns of the intestinal crypt towards epithelial differentiation and stem cell regulation. Naproxen demonstrated robust chemopreventive activity in a mouse co-clinical trial and gene expression profiles induced by naproxen in humans showed perfect discrimination of mice specimens with LS and PDOs treated with naproxen and control.

CONCLUSIONS

Naproxen is a promising strategy for immune interception in LS. We have discovered naproxen-induced gene expression profiles for their potential use as predictive biomarkers of drug activity.

TRIAL REGISTRATION NUMBER

gov Identifier: NCT02052908.

NCCN Guidelines Insights: Colorectal Cancer Screening, Version 2.2020

The NCCN Guidelines for Colorectal Cancer (CRC) Screening describe various colorectal screening modalities as well as recommended screening schedules for patients at average or increased risk of developing sporadic CRC. They are intended to aid physicians with clinical decision-making regarding CRC screening for patients without defined genetic syndromes. These NCCN Guidelines Insights focus on select recent updates to the NCCN Guidelines, including a section on primary and secondary CRC prevention, and provide context for the panel's recommendations regarding the age to initiate screening in average risk individuals and follow-up for low-risk adenomas.

Eflornithine plus Sulindac for Prevention of Progression in Familial Adenomatous Polyposis

BACKGROUND

The efficacy and safety of combination therapy with eflornithine and sulindac, as compared with either drug alone, in delaying disease progression in patients with familial adenomatous polyposis are unknown.

METHODS

We evaluated the efficacy and safety of the combination of eflornithine and sulindac, as compared with either drug alone, in adults with familial adenomatous polyposis. The patients were stratified on the basis of anatomical site with the highest polyp burden and surgical status; the strata were precolectomy (shortest projected time to disease progression), rectal or ileal pouch polyposis after colectomy (longest projected time), and duodenal polyposis (intermediate projected time). The patients were then randomly assigned in a 1:1:1 ratio to receive 750 mg of eflornithine, 150 mg of sulindac, or both once daily for up to 48 months. The primary end point, assessed in a time-to-event analysis, was disease progression, defined as a composite of major surgery, endoscopic excision of advanced adenomas, diagnosis of high-grade dysplasia in the rectum or pouch, or progression of duodenal disease.

RESULTS

A total of 171 patients underwent randomization. Disease progression occurred in 18 of 56 patients (32%) in the eflornithine-sulindac group, 22 of 58 (38%) in the sulindac group, and 23 of 57 (40%) in the eflornithine group, with a hazard ratio of 0.71 (95% confidence interval [CI], 0.39 to 1.32) for eflornithine-sulindac as compared with sulindac (P = 0.29) and 0.66 (95% CI, 0.36 to 1.24) for eflornithine-sulindac as compared with eflornithine. Among 37 precolectomy patients, the corresponding values in the treatment groups were 2 of 12 patients (17%), 6 of 13 (46%), and 5 of 12 (42%) (hazard ratios, 0.30 [95% CI, 0.07 to 1.32] and 0.20 [95% CI, 0.03 to 1.32]); among 34 patients with rectal or ileal pouch polyposis, the values were 4 of 11 patients (36%), 2 of 11 (18%), and 5 of 12 (42%) (hazard ratios, 2.03 [95% CI, 0.43 to 9.62] and 0.84 [95% CI, 0.24 to 2.90]); and among 100 patients with duodenal polyposis, the values were 12 of 33 patients (36%), 14 of 34 (41%), and 13 of 33 (39%) (hazard ratios, 0.73 [95% CI, 0.34 to 1.52] and 0.76 [95% CI, 0.35 to 1.64]). Adverse and serious adverse events were similar across the treatment groups.

CONCLUSIONS

In this trial involving patients with familial adenomatous polyposis, the incidence of disease progression was not significantly lower with the combination of eflornithine and sulindac than with either drug alone. (Funded by Cancer Prevention Pharmaceuticals; ClinicalTrials.gov number, NCT01483144; EudraCT number, 2012-000427-41.).

Abstract CT111: Naproxen chemoprevention promotes immune activation in Lynch syndrome colorectal mucosa

Patients diagnosed with germline mutations in MMR genes (Lynch Syndrome, LS) have up to 70-80% lifetime risk of colorectal cancer. Therefore, this high-risk population has the potential to benefit from effective chemopreventive strategies. Naproxen is an NSAID widely used for pain treatment with an excellent safety profile that has demonstrated to be more efficacious preventing colorectal cancer compared to aspirin in vivo using an intestinal tissue-specific mouse model of LS (VC-Msh2-LoxP). The ‘Naproxen trial' was designed to evaluate the modulation of PGE2 levels in colorectal mucosa, evaluate safety and tolerability, and discover novel molecular pathways involved in the chemopreventive activity of naproxen in LS patients. Methods: Participants were randomized to naproxen 440 mg (HD), 220 mg (LD) and placebo by mouth daily for 6 months. Modulation of prostaglandin levels, number of adverse events (AEs) observed in each treatment arm and gene expression profiles by next-generation sequencing (mRNAseq) in normal colorectal mucosa of LS patients after 6 months of intervention were examined. Results: Eighty participants diagnosed with LS were randomized, 25 participants to HD, 27 to LD, and 28 to placebo. From these patients, 54 were considered evaluable per-protocol analysis: 16 in the HD group, 15 in the LD and 23 in placebo. The level of prostaglandin E2 in the colorectal mucosa decreased significantly after treatment with both LD and HD naproxen when compared to placebo (-91.2%±14.1, -93.6%±7.9, and 23.8%±108.4, P-value&lt;0.001, respectively). Moreover, levels of PGE2 urinary metabolite (PGE-M) were significantly changed in both treatment groups when compared to placebo (-47.7%±56.9, -41.1%±40.5, 7.6%±94.3, P-Value&lt;0.018). The intervention was well tolerated, no severe AEs related to treatment were reported, and the total number of AEs was not different across treatment arms. LD and HD naproxen promoted the activity of the immune system by activating different immune cell types without any effect on lymphoid cellularity and changed the expression patterns of the intestinal crypt towards epithelial differentiation and stem cell regulation. Conclusions: Naproxen is a promising strategy for immune interception in LS that induces immune-modulation coupled with changes in the dynamics of the intestinal crypt. We have also discovered naproxen-induced gene expression profiles for their potential use as predictive biomarkers of drug activity.

Citation Format: Laura Reyes Uribe, Wenhui Wu, Ozkan Gelincik, Prashant V. Bommi, Alejandro Francisco-Cruz, Luisa M. Solis, Patrick M. Lynch, Ramona Lim, Elena Stoffel, Priyanka Kanth, N. Jewel Samadder, Maureen E. Mork, Melissa W. Taggart, Ginger L. Milne, Lawrence J. Marnett, Lana Vornik, Diane D. Liu, Maria Revuelta, Kyle Chang, Y. Nancy You, Levy Kopelovich, Ignacio I. Wistuba, J. Jack Lee, Shizuko Sei, Robert H. Shoemaker, Eva Szabo, Ellen Richmond, Asad Umar, Marjorie Perloff, Powell H. Brown, Steven M. Lipkin, Eduardo Vilar. Naproxen chemoprevention promotes immune activation in Lynch syndrome colorectal mucosa [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 CT111.

Colorectal cancer risk based on extended family history and body mass index

Family history and body mass index (BMI) are well-known risk factors for colorectal cancer (CRC), however, their joint effects are not well described. Using linked data for genealogy, self-reported height and weight from driver's licenses, and the Utah Surveillance, Epidemiology, and End-Results cancer registry, we found that an increasing number of first-degree relatives (FDR) with CRC is associated with higher standardized incidence ratio (SIR) for overweight/obese probands but not for under/normal weight probands. For probands with two CRC-affected FDRs, the SIR = 1.91 (95% CI [0.52, 4.89]) for under/normal weight probands and SIR = 4.31 (95% CI [2.46, 7.00]) for overweight/obese probands. In the absence of CRC-affected FDRs, any number of CRC-affected SDRs did not significantly increase CRC risk for under/normal weight probands, but for overweight/obese probands with at least three CRC-affected SDRs the SIR = 2.68 (95% CI [1.29, 4.93]). In the absence of CRC-affected FDRs and SDRs, any number of CRC-affected third-degree relatives (TDRs) did not increase risk in under/normal weight probands, but significantly elevated risk for overweight/obese probands with at least two CRC-affected TDRs was observed; SIR = 1.32 (95% CI [1.04, 1.65]). For nonsyndromic CRC, maximum midlife BMI affects risk based on family history and should be taken into account for CRC risk communication when possible.

Abstract IA35: Molecular characterization of sessile serrated adenoma/polyps: A risk factor for higher colorectal cancer that further associates with endometrial polyps in female African Americans

Colorectal cancer is the third leading cause of cancer-related deaths in the United States, and rates are highest among African Americans (AAs). Sessile serrated adenoma/polyps (SSA/Ps) may be precursors to up to 30% of all colorectal cancers. Flat and mucinous features make SSA/Ps difficult to detect and diagnose. As such, there is a need for specific sensitive molecular biomarkers for an accurate and reliable diagnosis. Our aim was to assess the diagnostic value of molecular biomarkers that may distinguish SSA/Ps from benign hyperplastic polyps (HPs) among AA SSA/P patients. We conducted a retrospective study of all colonoscopies (n=12,085) performed at Howard University Hospital (2010-2015), which confirmed 4,070 AA patients with polyps, including 252 with SSA/Ps. Gene expression and mutation frequency profiles were analyzed in a total of 47 patients (62 specimens: 29 SSA/Ps, 26 HPs, 3 tubular adenomas, and 4 normal tissues). We tested 4 transcripts (MUC6, FSCN1, SEMG1, and TRNP1) using qRT-PCR. MSI and BRAF mutations were analyzed. CIMP analysis was performed using CACNA1G, IGF2, NEUROG1, RUNX, SOCS, and MLH1. In a parallel study, we assessed the association between endometrial polyp occurrence in patients with different types of colorectal lesions. MUC6, SEMG1, TRNP1, and FSCN1 were significantly more expressed in SSA/Ps vs. HPs (P&lt;0.05; fold differences of 37.2, 10.7, 5.8 and 2.5, respectively). BRAF mutation was found in 55.6% of SSA/Ps vs. 12.0% in HPs (P = 0.001). The frequency of CIMP was higher in SSA/Ps but not statistically significant, while MSI was more prevalent in HPs (P &gt; 0.05). There was a higher loss of MLH1 expression in HPs than SSA/Ps (42.9% showing expression vs 70.3% IHC staining &gt;=2 in HPs and SSA/Ps). The SSA/Ps in our AA study were primarily distal (67%). In female patients, SSA/Ps associated with the higher frequency of endometrial polyps (8% vs. 2% in controls, p=0.003). Our results show that MUC6-SEMG1-TRNP1 expression and BRAF mutation have the strongest correlation with SSA/Ps. The distal location might help explain why MSI and CIMP may not be optimal molecular biomarkers in African American patients with SSA/Ps. These markers may be of high relevance for the diagnosis of ambiguous lesions and will benefit patients’ management for scheduling follow-ups based on the nature of index lesions. Females with colon lesions of the SSA/Ps type might benefit from a screening for an endometrial polyp in an age-independent manner.

Citation Format: Hassan Ashktorab, Saman Azam, Babak Shokrani, Edward Lee, Taraneh Arjomand, Priyanka Kanth, Don Delker, Adeyinka Laiyemo, John Caretheres, Mehdi Nouraie, Hassan Brim. Molecular characterization of sessile serrated adenoma/polyps: A risk factor for higher colorectal cancer that further associates with endometrial polyps in female African Americans [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr IA35.

Association of Sulindac and Erlotinib vs Placebo With Colorectal Neoplasia in Familial Adenomatous Polyposis: Secondary Analysis of a Randomized Clinical Trial

Importance

Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for colorectal polyps and cancer. A combination of sulindac and erlotinib led to a 71% reduction in duodenal polyp burden in a phase 2 trial.

Objective

To evaluate effect of sulindac and erlotinib on colorectal adenoma regression in patients with FAP.

Design, Setting, and Participants

Prespecified secondary analysis for colorectal adenoma regression was carried out using data from a double-blind, randomized, placebo-controlled trial, enrolling 92 patients with FAP, conducted from July 2010 to June 2014 in Salt Lake City, Utah.

Interventions

Patients were randomized to sulindac, 150 mg twice daily, and erlotinib, 75 mg daily (n = 46), vs placebo (n = 46) for 6 months.

Main Outcomes and Measurements

The total number of polyps in the intact colorectum, ileal pouch anal anastomosis, or ileo-rectum were recorded at baseline and 6 months. The primary outcomes were change in total colorectal polyp count and percentage change in colorectal polyps, following 6 months of treatment.

Results

Eighty-two randomized patients (mean [SD] age, 40 [13] years; 49 [60%] women) had colorectal polyp count data available for this secondary analysis: 22 with intact colon, 44 with ileal pouch anal anastomosis and 16 with ileo-rectal anastomosis; 41 patients received sulindac/erlotinib and 41 placebo. The total colorectal polyp count was significantly different between the placebo and sulindac-erlotinib group at 6 months in patients with net percentage change of 69.4% in those with an intact colorectum compared with placebo (95% CI, 28.8%-109.2%; P = .009).

Conclusion and Relevance

In this double-blind, placebo-controlled, randomized trial we showed that combination treatment with sulindac and erlotinib compared with placebo resulted in significantly lower colorectal polyp burden after 6 months of treatment. There was a reduction in polyp burden in both those with an entire colorectum and those with only a rectal pouch or rectum.

Trial Registration

clinicaltrials.gov Identifier: NCT01187901.

NCCN Guidelines Insights: Genetic/Familial High-Risk Assessment: Colorectal, Version 2.2019

Identifying individuals with hereditary syndromes allows for improved cancer surveillance, risk reduction, and optimized management. Establishing criteria for assessment allows for the identification of individuals who are carriers of pathogenic genetic variants. The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal provide recommendations for the assessment and management of patients with high-risk colorectal cancer syndromes. These NCCN Guidelines Insights focus on criteria for the evaluation of Lynch syndrome and considerations for use of multigene testing in the assessment of hereditary colorectal cancer syndromes.

Abstract 3159: Do molecular markers differentiate between sessile serrated adenoma/polyps and hyperplastic polyps

Background: A significant proportion of colorectal cancers, as much as up to 30%, develop through the alternate serrated pathway. The precursor lesions in this pathway comprise of sessile serrated adenomas or polyps (SSA/SSPs) and hyperplastic polyps (HPs), both with a varying risk-profile associated with them for progression into colorectal cancer. Although both types of polyps can be identified histologically, the clinical challenge for gastroenterologists and pathologists remain for risk-prediction as to which of these polyps have a higher likelihood for subsequent development and progression into colorectal cancer. These data highlight the imperative need for the development of more specific and objective markers that can adequately differentiate between the two types of colonic polyps.

Aim: The aim of our study was to determine a variety of molecular biomarkers that may distinguish SSA/Ps and HPs, and to establish biomarker profiles that associate with low vs. high-risk SSA/Ps.

Methods: We conducted a retrospective study of all colonoscopies (n=12,085) performed at the Howard University Hospital between January 2010 to December 2015; of which 83% were conducted in patients of African American (AA) descent (n=10,027). Among AAs, pathology reports confirmed 4,070 patients with polyps, including 252 with SSA/Ps. Gene expression and mutation frequency profiles were analyzed in a total of 47 patients which included 62 specimens (29 SSPs, 26 HP, 3 tubular adenomas (TA) and 4 normal colonic tissues). From a panel of 51 candidate transcripts, we validated 4 RNA markers (MUC6, FSCN1, SEMG1, and TRNP1) using qRT-PCR. MSI and BRAF mutations were also analyzed. CIMP analysis was performed for the aberrant methylation of CACNA1G, IGF2, NEUROG1, RUNX, SOCS and MLH1. The frequency of gender, age groups, anatomic location, clinical/pathological symptoms and reason for colonoscopy in SSA/P patients was analyzed. The median age range for SSA/P diagnosis was between 50 to 64 years.

Results: MUC6, SEMG1, TRNP1, and FSCN1 expression was significantly higher in SSA/Ps vs. HPs (P &lt; 0.05); with corresponding fold differences of 37.2 10.7, 5.8 and 2.5, respectively. BRAF mutations were found in 55.6% of SSA/Ps as opposed to 12.0% of HPs (P &lt; 0.05). The frequency of CIMP was higher in SSA/Ps and correlated with BRAF mutation, while the degree of MSI was more prevalent in HP (P &gt; 0.05). SSA/P lesions were distal (67%).

Conclusion: Our results show that MUC6 and SEMG1 expression and BRAF mutation have the strongest correlation with SSA/Ps in comparison to HPs. In addition, SSA/Ps were predominantly distal in location. These are novel and distinguishing features compared to the published literature in non-AA populations and may help explain why MSI and CIMP, usually linked to proximal lesions, are not optimal molecular biomarkers in AA patients with such serrated lesions.

Note: This abstract was not presented at the meeting.

Citation Format: Hassan Ashktorab, Saman Azam, Taraneh Tarjoman, Priyanka Kanth, Edward Lee, Mehdi Nouraie, Nazli Atefi, Babak Shokrani, Adeyinka Laiyemo, Ajay Goel, Mark W. Hazel, Ruoxin Yao, Angela Snow, Deborah Neklason, Don Delker, Hassan Brim. Do molecular markers differentiate between sessile serrated adenoma/polyps and hyperplastic polyps [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3159.

Small RNA sequencing of sessile serrated polyps identifies microRNA profile associated with colon cancer

Sessile serrated adenoma/polyps (SSA/Ps) of the colon account for 20-30% of all colon cancers. Small non-coding RNAs, including microRNAs (miRNAs), may function as oncogenes or tumor suppressor genes involved in cancer development. Small RNA sequencing (RNA-seq) was used to characterize miRNA profiles in SSA/Ps, hyperplastic polyps (HPs), adenomatous polyps and paired uninvolved colon. Our 108 small RNA-seq samples' results were compared to small RNA-seq data from 212 colon cancers from the Cancer Genome Atlas. Twenty-three and six miRNAs were differentially expressed in SSA/Ps compared to paired uninvolved colon and HPs, respectively. Differential expression of MIR31-5p, MIR135B-5p and MIR378A-5p was confirmed by RT-qPCR. SSA/P-specific miRNAs are similarly expressed in colon cancers containing genomic aberrations described in serrated cancers. Correlation of miRNA expression with consensus molecular subtypes suggests more than one subtype is associated with the serrated neoplasia pathway. Canonical pathway analysis suggests many of these miRNAs target growth factor signaling pathways.

Patterns of family communication and preferred resources for sharing information among families with a Lynch syndrome diagnosis

OBJECTIVES

To explore patterns of communication among families with a Lynch syndrome diagnosis and understand what resources could facilitate family communication.

METHODS

127 probands (i.e., first person in family with identified mutation) and family members participated in semi-structured interviews about: how they learned about the Lynch syndrome diagnosis, with whom they shared genetic test results, confidence in sharing results with other family members, and helpfulness of educational resources.

RESULTS

Both probands and family members were most likely to share genetic test results with parents and siblings, and least likely to share results with aunts, uncles, and cousins. Most participants felt very confident sharing their test results with family members, but reported that certain topics such as cancer risk were challenging to convey. Probands reported the most helpful resources to be access to a specialty clinic or website, while family members described general printed materials as most helpful.

CONCLUSIONS

Families affected by Lynch syndrome may experience barriers to communication with more distant relatives, and may benefit from receiving specific resources (e.g., websites about Lynch syndrome, print materials) to facilitate family communication.

PRACTICE IMPLICATIONS

Providers could emphasize the need to share information with more distant family members and provide appropriate supportive resources.

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.

Variables affecting penetrance of gastric and duodenal phenotype in familial adenomatous polyposis patients

BACKGROUND

Patients with familial adenomatous polyposis (FAP) frequently undergo colectomy to reduce the 70 to 90% lifetime risk of colorectal cancer. After risk-reducing colectomy, duodenal cancer and complications from duodenal surgeries are the main cause of morbidity. Our objective was to prospectively describe the duodenal and gastric polyp phenotype in a cohort of 150 FAP patients undergoing pre-screening for a chemoprevention trial and analyze variables that may affect recommendations for surveillance.

METHODS

Individuals with a diagnosis of FAP underwent prospective esophagogastroduodenoscopy using a uniform system of mapping of size and number of duodenal polyps for a 10 cm segment. Gastric polyps were recorded as the total number.

RESULTS

The distribution of the count and sum diameter of duodenal polyps were statistically different in two genotype groups, those with APC mutations associated with classic FAP had a greater count (median 17) and sum diameter of polyps (median 32 mm) than those with APC mutations associated with attenuated FAP (median count 4 and median sum diameter of 7 mm) (p < 0.0001). The number of gastric polyps did not differ based on genotype (p = 0.67) but advancing age correlated with severity of gastric polyposis (p = 0.019). Spigelman (modified) staging of II or greater was found in 88% of classic FAP patients and 48% attenuated FAP patients. Examples of severe and mild upper GI phenotype are observed in patients with identical APC mutations, showing that the APC mutation location is not absolutely predictive of an upper GI phenotype.

CONCLUSIONS

Most FAP patients have duodenal and gastric polyps which become more prevalent and advanced with age. Standard upper endoscopic surveillance is recommended based on personal history independent of APC mutation location.

TRIAL REGISTRATION

NCT 01187901 registered August 24, 2010, prospective to enrollment.

Abstract CT065: A phase Ib biomarker trial of naproxen in patients at risk for DNA mismatch repair deficient colorectal cancer

Background: Patients diagnosed with Lynch Syndrome (LS) have an approximately 70% lifetime risk of colorectal cancer (CRC) due to the presence of germline mutations in the mismatch repair (MMR) genes. Cyclooxygenases (COX) are key enzymes in the metabolism of Prostaglandins (PGs) being COX-2 induced at sites of inflammation as well as in ~85% of CRC and 50% of premalignant adenomas. Non-steroidal anti-inflammatory drugs (NSAIDs) such as Aspirin and Naproxen exert their therapeutic effects through the inhibition of both COX-1 and COX-2, which causes a reduction in PGs. However, other known non-canonical effects include inhibition of cell growth, induction of cell cycle arrest, and apoptosis. Aspirin has demonstrated chemopreventive properties in LS patients at high doses. Naproxen is widely used for the treatment of pain with an excellent safety profile. In addition, pre-clinical in vivo data using a genetically-engineered mouse model of Lynch Syndrome (Villin-Cre;Msh2LoxP/LoxP) has demonstrated that Naproxen is the most effective NSAID in preventing colorectal tumors and has shown to be superior to Aspirin. The present clinical trial was designed to assess the safety and tolerability of long-term chemoprevention with Naproxen in LS and also to discover novel biomarkers of drug activity.

Methods: LS patients at 4 participating sites (The University of Texas MD Anderson Cancer Center, Dana Farber Cancer Institute, The University of Michigan Comprehensive Cancer Center, and Huntsman Cancer Institute) were randomly assigned to Naproxen 440 mg, 220 mg, or placebo once daily for 6 months. To determine the safety profile and tolerability of Naproxen, adverse events (AEs) were reported using CTCAE V4.03. To assess the activity of the drug intervention we measured Prostaglandin E2 (PGE2) levels in normal colorectal mucosa, its metabolite in urine (PGE-M), levels of Naproxen in plasma and colorectal mucosa at baseline and 6 months after treatment. Response to treatment was defined as 30% reduction in PGE2 levels. Results: A total of 86 patients were registered to this study, 28 randomized to Placebo, 25 to Naproxen 440 mg, and 27 to Naproxen 220 mg. Mean age was 44.6 years, 64% of the patients were females, 53% were unaffected carriers, and MLH1 and MSH2 were the most frequently mutated genes. Fifty-eight completed the study (67%). A total of 183 AEs were recorded in 61 patients, 77% were unrelated or unlikely related to the treatment, only 8 were reported as grade 3 AEs and none of these were related to Naproxen. In the group that received Naproxen at 440 mg, the levels of Naproxen in plasma and normal colorectal mucosa were the highest and the levels of PGE2 and PGE-M were significantly lower when compared to patients in the Placebo arm (P=0.027). In addition, the response rate was the highest among patients receiving Naproxen at 440 mg daily compared to Naproxen at 220 mg and Placebo (87.5% vs 75% vs 13%, respectively).

Conclusions: The tolerance and safety of long-term chemoprevention with Naproxen at a dose of 440 mg for 6 months was excellent. There was evidence of decreased inflammatory activity among LS patients treated with high dose Naproxen compared to Placebo. Biomarker studies to discover novel non-canonical effects of Naproxen via modulation of miRNA and mRNA profiles using next-generation sequencing approaches are currently ongoing.

Citation Format: Laura Reyes Uribe, Ramona Lin, Elena M. Stoffel, N. Jewel Samadder, Patrick Lynch, Priyanka Kanth, Ginger Milne, Lawrence J. Marnett, Valerie Sepeda, Diane D Liu, Y. Nancy You, Lana A. Vornik, J. Jack Lee, Ellen Richmond, Asad Umar, Marjorie Perloff, Steven M. Lipkin, Powel H. Brown, Eduardo Vilar-Sanchez. A phase Ib biomarker trial of naproxen in patients at risk for DNA mismatch repair deficient colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT065.

Intramucosal lipomas of the colon implicate Cowden syndrome

Intramucosal lipomas are rare and easily overlooked by pathologists, despite their diagnostic significance for Cowden syndrome (PTEN hamartoma tumor syndrome), an inherited multiorgan cancer syndrome. Only 25-35% of patients harbor identifiable PTEN mutations, thus clinical features, like intramucosal lipomas, remain the mainstay of diagnosis. The significance and diagnostic approach to intramucosal lipomas have not been thoroughly addressed in the literature. Intramucosal lipomas are mimicked by pseudolipomatosis coli, an artifactual mucosal gas infiltration from endoscopic insufflation. This differential was investigated by morphology and S-100 immunohistochemistry. Twenty-five colonic intramucosal lipomas were identified from 176 archival gastrointestinal lipomas from 1998 to 2017. Controls included 40 submucosal lipomas and 30 pseudolipomatoses. S-100 immunohistochemistry on all 95 lesions confirmed delicate fat vacuole membranous and nuclear S-100 staining in lipomas absent from pseudolipomatoses. Differentiating morphology between intramucosal lipoma and pseudolipomatosis, respectively, included consistently large, regular fat vacuoles (92% vs 7%), associated spindle cells (80% vs 0%), and mucosal lymphoid aggregate involvement (12% vs 80%). Of the 25 intramucosal lipomas, five patients (20%) had confirmed Cowden syndrome (four with PTEN mutations). In four of these Cowden patients, the intramucosal lipoma was the index diagnostic lesion. Three (12%) intramucosal lipoma patients had additional clinical features associated with Cowden syndrome, but did not meet the diagnostic criteria. Sporadic-type intramucosal lipomas were identified in 17 patients (68%) without evidence of Cowden syndrome, including three with normal PTEN genetic testing. No distinguishing endoscopic or pathologic polyp features were identified between sporadic and syndromic intramucosal lipomas. These data provide evidence that intramucosal lipomas are important harbingers of Cowden syndrome, making up approximately one-third of this series, the largest in the literature. We also show for the first time that two-thirds of intramucosal lipomas are sporadic. Gastrointestinal pathologists, gastroenterologists, and geneticists should increase their awareness of this subtle but diagnosable lesion strongly associated with Cowden syndrome.

Chemoprevention with Cyclooxygenase and Epidermal Growth Factor Receptor Inhibitors in Familial Adenomatous Polyposis Patients: mRNA Signatures of Duodenal Neoplasia

To identify gene expression biomarkers and pathways targeted by sulindac and erlotinib given in a chemoprevention trial with a significant decrease in duodenal polyp burden at 6 months (P < 0.001) in familial adenomatous polyposis (FAP) patients, we biopsied normal and polyp duodenal tissues from patients on drug versus placebo and analyzed the RNA expression. RNA sequencing was performed on biopsies from the duodenum of FAP patients obtained at baseline and 6-month endpoint endoscopy. Ten FAP patients on placebo and 10 on sulindac and erlotinib were selected for analysis. Purity of biopsied polyp tissue was calculated from RNA expression data. RNAs differentially expressed between endpoint polyp and paired baseline normal were determined for each group and mapped to biological pathways. Key genes in candidate pathways were further validated by quantitative RT-PCR. RNA expression analyses of endpoint polyp compared with paired baseline normal for patients on placebo and drug show that pathways activated in polyp growth and proliferation are blocked by this drug combination. Directly comparing polyp gene expression between patients on drug and placebo also identified innate immune response genes (IL12 and IFNγ) preferentially expressed in patients on drug. Gene expression analyses from tissue obtained at endpoint of the trial demonstrated inhibition of the cancer pathways COX2/PGE2, EGFR, and WNT. These findings provide molecular evidence that the drug combination of sulindac and erlotinib reached the intended tissue and was on target for the predicted pathways. Furthermore, activation of innate immune pathways from patients on drug may have contributed to polyp regression. Cancer Prev Res; 11(1); 4-15. ©2017 AACRSee related editorial by Shureiqi, p. 1.

Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism

Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells.

Abstract LB-074: Regression of duodenal neoplasia in familial adenomatous polyposis patients using COX and EGFR inhibition: A randomized placebo-controlled trial

The objective of this trial was to test the effect of a combination of COX and EGFR inhibition on duodenal adenoma progression in patients with familial adenomatous polyposis (FAP). FAP is caused by mutations in the APC gene and is characterized by the development of hundreds of colorectal adenomas and colorectal cancer. FAP patients are also at increased risk for duodenal neoplasia with a ∼10% lifetime risk of duodenal carcinoma. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful. Preclinical data has illustrated that a combination of cyclooxygenase (COX) and epidermal growth factor (EGFR) inhibition diminishes small intestinal adenoma development by 87% in mice with germline Apc mutations. Therefore, we conducted a double blind, randomized, placebo-controlled trial in which FAP patients received combination therapy with 150 mg sulindac twice per day and 75 mg erlotinib daily or placebo for 6 months (NCT01187901). The total number and diameter of polyps in a 10cm segment of the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden, calculated as the sum of the diameters of polyps. We also evaluated RNA expression in duodenal tissue and polyps at endpoint from 10 patients on drug and 10 patients on placebo by RNA sequencing. Seventy-three randomized patients were included in the intention to treat analysis. Over six months, the median change in total duodenal polyp burden was an increase of 8.0 mm from baseline burden in the placebo group (23.0 to 31.0 mm) and the median change in the sulindac-erlotinib group was a decrease of 8.5 mm (29.0 to 19.5 mm). The estimated net difference in change between the two groups was -19.0 mm (95% CI: -32.0, -10.9; P&lt;0.001). Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of patients receiving treatment and 20% of patients receiving placebo (P&lt;0.001). We identified ∼ 750 differentially expressed genes (fold ≥ 2, false discovery rate &lt; 0.05) in polyps from patients on placebo as compared with patient-matched normal duodenum which were unchanged in polyps from patients on drug. These differentially expressed genes suggested increased EGFR, prostaglandin E2 (PGE2 or COX2) and WNT signaling in duodenal polyps from patients on placebo but not on drug. In duodenal tissue from patients on drug when compared to tissue from patients on placebo, we identified differentially expressed genes suggestive of a reactivated immune response including interferon gamma and interleukin 12 signaling; a possible mechanism for the regression of duodenal polyps observed in drug treated patients. In conclusion, combined chemoprevention with sulindac and erlotinib in FAP patients is effective to lower duodenal polyp burden, block COX2 and EGFR activity, and may reactivate immune surveillance. At the doses tested, however, frequent adverse events may limit the use of these medications.

Part of this abstract was presented as part of a preliminary presentation.

Citation Format: Deborah W. Neklason, Don A. Delker, Kenneth M. Boucher, Priyanka Kanth, Kathryn Byrne, Philip Bernard, Wade Samowitz, Michelle W. Done, Therese Berry, Lisa Pappas, Laurel Smith, Danielle Sample, Rian Davis, Matthew K. Topham, Randall W. Burt, Scott K. Kuwada, N Jewel Samadder. Regression of duodenal neoplasia in familial adenomatous polyposis patients using COX and EGFR inhibition: A randomized placebo-controlled trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-074.

Gene Signature in Sessile Serrated Polyps Identifies Colon Cancer Subtype

Sessile serrated colon adenoma/polyps (SSA/P) are found during routine screening colonoscopy and may account for 20% to 30% of colon cancers. However, differentiating SSA/Ps from hyperplastic polyps (HP) with little risk of cancer is challenging and complementary molecular markers are needed. In addition, the molecular mechanisms of colon cancer development from SSA/Ps are poorly understood. RNA sequencing (RNA-Seq) was performed on 21 SSA/Ps, 10 HPs, 10 adenomas, 21 uninvolved colon, and 20 control colon specimens. Differential expression and leave-one-out cross-validation methods were used to define a unique gene signature of SSA/Ps. Our SSA/P gene signature was evaluated in colon cancer RNA-Seq data from The Cancer Genome Atlas (TCGA) to identify a subtype of colon cancers that may develop from SSA/Ps. A total of 1,422 differentially expressed genes were found in SSA/Ps relative to controls. Serrated polyposis syndrome (n = 12) and sporadic SSA/Ps (n = 9) exhibited almost complete (96%) gene overlap. A 51-gene panel in SSA/P showed similar expression in a subset of TCGA colon cancers with high microsatellite instability. A smaller 7-gene panel showed high sensitivity and specificity in identifying BRAF-mutant, CpG island methylator phenotype high, and MLH1-silenced colon cancers. We describe a unique gene signature in SSA/Ps that identifies a subset of colon cancers likely to develop through the serrated pathway. These gene panels may be utilized for improved differentiation of SSA/Ps from HPs and provide insights into novel molecular pathways altered in colon cancer arising from the serrated pathway. Cancer Prev Res; 9(6); 456-65. ©2016 AACR.

Effect of Sulindac and Erlotinib vs Placebo on Duodenal Neoplasia in Familial Adenomatous Polyposis: A Randomized Clinical Trial

IMPORTANCE

Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal polyps and cancer. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful.

OBJECTIVE

To evaluate the effect of a combination of sulindac and erlotinib on duodenal adenoma regression in patients with FAP.

DESIGN, SETTING, AND PARTICIPANTS

Double-blind, randomized, placebo-controlled trial, enrolling 92 participants with FAP, conducted from July 2010 through June 2014 at Huntsman Cancer Institute in Salt Lake City, Utah.

INTERVENTIONS

Participants with FAP were randomized to sulindac (150 mg) twice daily and erlotinib (75 mg) daily (n = 46) vs placebo (n = 46) for 6 months.

MAIN OUTCOMES AND MEASURES

The total number and diameter of polyps in the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden at 6 months. Polyp burden was calculated as the sum of the diameters of polyps. The secondary outcomes were change in total duodenal polyp count, change in duodenal polyp burden or count stratified by genotype and initial polyp burden, and percentage of change from baseline in duodenal polyp burden.

RESULTS

Ninety-two participants (mean age, 41 years [range, 24-55]; women, 56 [61%]) were randomized when the trial was stopped by the external data and safety monitoring board because the second preplanned interim analysis met the prespecified stopping rule for superiority. Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of participants receiving treatment and 20% of participants receiving placebo (P < .001). Only 2 participants experienced grade 3 adverse events. [table: see text].

CONCLUSIONS AND RELEVANCE

Among participants with FAP, the use of sulindac and erlotinib compared with placebo resulted in a lower duodenal polyp burden after 6 months. Adverse events may limit the use of these medications at the doses used in this study. Further research is necessary to evaluate these preliminary findings in a larger study population with longer follow-up to determine whether the observed effects will result in improved clinical outcomes.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT 01187901.

RNA sequencing of sessile serrated colon polyps identifies differentially expressed genes and immunohistochemical markers

BACKGROUND

Sessile serrated adenomas/polyps (SSA/Ps) may account for 20-30% of colon cancers. Although large SSA/Ps are generally recognized phenotypically, small (<1 cm) or dysplastic SSA/Ps are difficult to differentiate from hyperplastic or small adenomatous polyps by endoscopy and histopathology. Our aim was to define the comprehensive gene expression phenotype of SSA/Ps to better define this cancer precursor.

RESULTS

RNA sequencing was performed on 5' capped RNA from seven SSA/Ps collected from patients with the serrated polyposis syndrome (SPS) versus eight controls. Highly expressed genes were analyzed by qPCR in additional SSA/Ps, adenomas and controls. The cellular localization and level of gene products were examined by immunohistochemistry in syndromic and sporadic SSA/Ps, adenomatous and hyperplastic polyps and controls. We identified 1,294 differentially expressed annotated genes, with 106 increased ≥10-fold, in SSA/Ps compared to controls. Comparing these genes with an array dataset for adenomatous polyps identified 30 protein coding genes uniquely expressed ≥10-fold in SSA/Ps. Biological pathways altered in SSA/Ps included mucosal integrity, cell adhesion, and cell development. Marked increased expression of MUC17, the cell junction protein genes VSIG1 and GJB5, and the antiapoptotic gene REG4 were found in SSA/Ps, relative to controls and adenomas, were verified by qPCR analysis of additional SSA/Ps (n = 21) and adenomas (n = 10). Immunohistochemical staining of syndromic (n≥11) and sporadic SSA/Ps (n≥17), adenomatous (n≥13) and hyperplastic (n≥10) polyps plus controls (n≥16) identified unique expression patterns for VSIG1 and MUC17 in SSA/Ps.

CONCLUSION

A subset of genes and pathways are uniquely increased in SSA/Ps, compared to adenomatous polyps, thus supporting the concept that cancer develops by different pathways in these phenotypically distinct polyps with markedly different gene expression profiles. Immunostaining for a subset of these genes differentiates both syndromic and sporadic SSA/Ps from adenomatous and hyperplastic polyps.