Evaluating colonoscopy screening intervals in patients with Lynch syndrome from a large Canadian registry

A study at the University of Toronto evaluated how colonoscopy intervals impact colorectal cancer (CRC) incidence in patients with Lynch syndrome (LS). Among 429 LS patients with a median follow-up of 9,2 years, 44 (10%) developed CRC. Any new adenoma detected at screening decreased 10-year CRC incidence by 11.3%. For MLH1, MLH2, and MLH6 carriers, a screening interval of 1-2 years versus 2-3 years led to a 20-year cumulative CRC risk reduction of almost 30% in females and approximately 15% in males. Individuals without any adenomas detected at screening (53.4% of LS carriers) had an increased 20-year CRC risk of 25.7% among females and 57.2% among males when compared with those with screening-detected adenomas. The authors conclude that the recommended colonoscopy interval of 1-2 year is efficient at detecting adenomas and reducing CRC risk. The observation that more than half of LS patients never had an adenoma detected warrants further investigation about a possible adenoma-free pathway.