Adenomas and Beyond: Colonoscopy Surveillance, Racial and Socioeconomic Disparities in Lynch Syndrome.

BACKGROUND AND AIMS: Pathogenic mutations in the mismatch repair (MMR) genes cause Lynch syndrome. Adenoma resection can prevent colorectal cancer (CRC), but the occurrence of precancerous lesions is understudied in Lynch syndrome. METHODS: Using retrospective cohort data, we examined racial and socioeconomic differences in the occurrence of adenoma, sessile serrated lesions (SSLs), and CRC during the first colonoscopy. We also estimated the association between MMR subtype and time to adenoma or SSL occurrence during follow-up colonoscopies. RESULTS: Of the 187 patients included in this study, the most common MMR subtype identified was MSH6 (31.0%). At first colonoscopy, 23% of patients had SSLs, 8.6% had adenomas, and 17.1% of patients had CRC. There was no difference by race or socioeconomic status (SES) in the occurrence of adenoma or SSL at first colonoscopy, but patients of lower SES had greater odds of having CRC (odds ratio: 1.24; 95% confidence interval [CI]: [1.01, 1.52]). During follow-up of patients with normal first colonoscopy, the odds of adenoma or SSL were higher among MSH6 compared to MLH1 (hazard ratio [HR]: 3.71; 95% CI: [1.08, 12.78]) and MSH2 carriers (HR: 9.52; 95% CI: [2.32, 39.11]). Among those with adenoma or SSL at first colonoscopy, MSH6 carriers were more likely to develop adenoma or SSL during follow-up compared to MLH1 carriers (HR: 3.68; 95% CI: [1.02, 13.26]). CONCLUSION: Adenoma and SSL were highest among MSH2 carriers at first colonoscopy, while MSH6 carriers had the highest risk of adenomas and SSLs during follow-up. Patients from lower SES backgrounds had higher odds of CRC at first colonoscopy.