Table 23.

Statements pertaining to MUTYH-associated polyposis-related colonic manifestations—extended version

Statements
MAP.LGM.1 Is lower-GI tract surveillance recommended? Lower-GI tract surveillance is recommended in individuals with biallelic MUTYH pathogenic variants.
MAP.LGM.2 From what age should colonoscopy surveillance be performed? Colonoscopy surveillance, in the absence of symptoms, should generally start at the age of 18 years, but exceptionally may be started earlier, based upon family history.
MAP.LGM.3 What are the recommended intervals of colonoscopy/endoscopic surveillance? The surveillance interval should be 1–2 yearly but may be personalized according to phenotype (polyp burden).
MAP.LGM.4 Which patient characteristics determine the indication for prophylactic colonic resection? A: Most MAP patients present with an a-FAP-like colorectal polyposis. For these patients, endoscopic resection of colorectal adenomas may be preferred over surgery. B: If surgery is considered, it should be discussed in a multidisciplinary setting. The discussion must consider the polyp burden (colonic and rectal), age, co-morbidities, and the patient’s views, as well as their compliance with endoscopic surveillance. C: The type of surgery depends on the rectal polyp burden. Consider colectomy with IRA as the first option. If there is dense rectal polyposis that cannot be managed endoscopically, consider proctocolectomy with IPAA. D: Prophylactic surgery is not recommended in patients with pathogenic variants in MUTYH who have not developed colorectal polyps or cancer.
MAP.LGM.5 What is the recommended extent of resection/surgery according to the patient’s characteristics? MAP patients may benefit from a total colectomy instead of a segmental colectomy when they present with or without confirmed colorectal cancer. However, patients who have received thorough counselling may choose to undergo a segmental colectomy instead.
MAP.LGM.6 Is surveillance of the remaining lower-GI tract indicated after surgery? A: Lower-GI tract surveillance is recommended in MAP patients. The surveillance interval should be 1–2 yearly but may be personalized according to phenotype. B: In patients having proctocolectomy with IPAA, endoscopic surveillance of the pouch is recommended post-surgery.

a-FAP, attenuated familial adenomatous polyposis; GI, gastrointestinal; IPAA, ileal pouch anal anastomosis; IRA, ileorectal anastomosis; MAP, MUTYH-associated polyposis.