Clinical Management of Oligopolyposis of Unknown Etiology

Cancer risk management for adenomatous oligopolyposis (10–99 colonic adenomas) depends upon whether the oligopolyposis results from a defined hereditary syndrome. Herein, we summarize genetic testing strategies for evaluation of oligopolyposis and outline colonoscopy and extra-colonic surveillance for individuals without a detectable hereditary syndrome, who have a condition referred to as oligopolyposis of unknown etiology (OPUE). Multi-gene panel genetic testing is appropriate for individuals with 10 or more cumulative colonic adenomas, yet a significant proportion of these individuals lack a molecular diagnosis and are defined clinically as having OPUE. Current consensus guidelines for OPUE surveillance support colonoscopy every 1–2 years with consideration of surgery if polyp clearance cannot be achieved. Data regarding extra-colonic surveillance is scant; however, screening of the upper gastrointestinal tract, thyroid, and small bowel may be considered on an individualized basis, similar to current clinical practices for familial adenomatous polyposis, despite a lack of strong supporting evidence. Multi-gene panel genetic testing should be recommended for all individuals with colonic oligopolyposis. Management of OPUE, especially extra-colonic surveillance, remains a challenging area of practice. It is crucial for individuals with OPUE to maintain contact with a specialized gastrointestinal genetics program, as genetic testing capabilities and medical recommendations will continue to evolve.