Weiss, Jennifer M.

Patients with familial adenomatous polyposis (FAP) are at increased risk of developing cancer, with the most common sites being colorectal, duodenal/ampullary and thyroid. In the last decade, an alarming increase in gastric cancer has been reported in the Western FAP population. These cancers are often diagnosed at an advanced stage with poor prognosis, even in patients undergoing regular upper endoscopic surveillance. Most gastric cancers in Western patients with FAP occur in the proximal stomach, where a carpeting of fundic gland polyposis hampers visualization of gastric cancer and its precursor lesions during endoscopic surveillance. Although fundic gland polyps are the most prevalent proximal polyp, several different dysplastic lesions can be found in the stomachs of patients with FAP. including fundic gland polyps with dysplasia, foveolar-type adenomas, pyloric gland adenomas, and intestinal-type adenomas. Although adenomas are the most likely precursors to gastric cancer, the exact lesions responsible for gastric cancer in FAP are not yet fully understood. This review focuses on gastric polyposis and the characteristics of gastric cancer in Western patients with FAP, including risk factors, lesion detection, surveillance and management of gastric polyposis, and areas for future research.

Gastric cancer is a significant global health concern, with CDH1-associated gastric cancer representing a small but important subset of cases. Historically, individuals with CDH1 pathogenic germline variants were advised to undergo prophylactic total gastrectomy due to the high reported risk of gastric cancer and the limited sensitivity of upper endoscopy in detecting signet ring cell carcinoma (SRCC). However, emerging data suggest that the cumulative lifetime risk of advanced gastric cancer among CDH1 germline pathogenic variant carriers is lower than previously thought, and early-stage SRCC detected on endoscopy does not necessarily indicate imminent—or even eventual—progression to advanced cancer. The near-universal presence of T1a SRCC in gastrectomy specimens from asymptomatic CDH1 pathogenic variant carriers calls into question the reflexive recommendation for gastrectomy, including upon detection of SRCC during surveillance. Furthermore, the morbidity and quality-of-life impact associated with total gastrectomy require careful consideration. Active endoscopic surveillance has shown promise as an alternative management strategy for gastrectomy in patients lacking indicators of >T1a SRCC, though current data are limited by short follow-up periods and selection bias. This review synthesizes recent findings on the natural history of CDH1-associated gastric cancer and evaluates the risks and benefits of gastrectomy versus active endoscopic surveillance, with the goal of helping clinicians provide personalized and evidence-based recommendations for patients with CDH1 pathogenic variants.

Multigene panel testing has allowed for the detection of a growing number of inherited pathogenic/likely pathogenic variants in people at high risk of cancer, including endometrial cancer (EC). Hereditary syndromes associated with EC include Lynch syndrome, PTEN hamartoma tumor syndrome, and Peutz-Jeghers syndrome. This manuscript provides the latest recommendations from the NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric on the screening and management of EC in patients at high risk for these syndromes, as well as the advantages and limitations of multigene panel testing. This manuscript also describes recent updates to these guidelines regarding de-implementation of colon cancer screening in individuals with CHEK2 pathogenic/likely pathogenic variants, based on the most up-to-date evidence regarding the association between CHEK2 pathogenic/likely pathogenic variants and colon cancer risk.

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 at which to initiate screening in average-risk individuals and those with increased risk based on personal history of childhood, adolescent, and young adult cancer.

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.