Duodenal adenomas and cancer in MUTYH-associated polyposis: an international cohort study

Although duodenal adenomas and cancer appear to occur significantly less frequently in autosomal recessive MUTYH-associated polyposis (MAP) than in autosomal dominant familial adenomatous polyposis (FAP),1 current guidelines recommend similar endoscopic surveillance for both disorders.2-4 This involves gastro-duodenoscopy starting at 25 to 35 years of age and repeated at intervals determined by Spigelman staging based on the number, size, histological type and degree of dysplasia of adenomas, and by ampullary staging. Case reports of duodenal cancers in MAP suggest that they may develop in the absence of advanced Spigelman stage benign disease and even without coexisting adenomas.1 Recent molecular analyses suggest thatMAPduodenal adenomashave a higher mutational burden than FAP adenomas and are more likely to harbor oncogenic drivermutations, such as those in KRAS.5 These apparent differences in the biology and natural history of duodenal polyposis in FAP and MAP challenge the assumption that the same surveillance should be applied in both conditions