P1936 - Racial Differences in Pre-Cancerous Colorectal Polyps and Colorectal Cancer During Surveillance Colonoscopy Among Patients With Lynch Syndrome: Experiences From a Mid-Atlantic Healthcare System

Joseph Atarere, MD, MPH¹, Mariah Malak Bilalaga, MD¹, Ramya Vasireddy, MBBS¹, Boniface Mensah, MBChB, MPH¹, Greeshma Gaddipati, MBBS¹, Simardeep Singh, MBBS¹, Ted Akhiwu, MBBS, MPH¹, Stephanie M. Woo, MD², Priyanka Kanth, MD^2
1MedStar Union Memorial Hospital, Baltimore, MD; ²MedStar Georgetown University Hospital, Washington, DC

Introduction: Lynch syndrome (LS) is the most common hereditary form of colorectal cancer (CRC) caused by mutations in the mismatch repair (MMR) system. Due to the early onset of CRC, all carriers of LS are offered colonoscopies starting at 20-25 years of age. Blacks/African Americans (AA) have the highest mortality from CRC and previous studies have shown that advanced adenomas are more common during screening colonoscopies in Blacks/AAs compared to Whites. In this study, we aimed to assess if racial disparities in the prevalence of precancerous lesions and CRC persist among high-risk patients with LS.

Methods: We extracted data from a retrospective cohort study of patients in a large Mid-Atlantic healthcare system with a germline diagnosis of LS. We included those who had completed ≥ 1 colonoscopy between April 13^th, 2005, and February 27^th, 2024. The primary outcome of interest was the finding on baseline colonoscopy [negative, adenoma, sessile serrated polyp (SSP) or CRC]. The primary independent variable was race, categorized as White, Black/AA and Others. We also included data on genetic mutations (MLH1, MSH2, MSH6, PMS2 and EPCAM), age, sex, and smoking status. We described the population characteristics by race and compared colonoscopy findings at baseline by mutation using stacked bar charts. Using an age and mutation-adjusted logistic regression model, we evaluated racial disparities in detection of adenoma, SSP or CRC on baseline colonoscopy.

Results: A total of 173 patients were included this study of which 129 (74.6%) were of White race. MSH6 (31.8%) was the most common mutation subtype identified. Over half (52.0%) of participants had normal findings while 16.2% had CRC on baseline colonoscopy (Table 1). The proportion of CRC was highest among those with MLH1 (25.0%) and lowest in MSH2 (8.3%). Among those without CRC, the proportion of precancerous lesions (SSP and adenomas) was highest with MSH2 (45.5%) and lowest with PMS2 (16.0%) (fig 1). In the adjusted model, there was no significant difference in colonoscopy findings by race [OR 1.32 for Black compared to White; 95% CI (0.57, 3.07)].

Discussion: CRC and precancerous lesions were more common among MLH1 and MSH2 respectively. We found no evidence of a difference in the proportion of CRC and precancerous lesions by race on baseline colonoscopy which is reassuring. A significant number of patients had CRC at baseline highlighting the need for more effective genetic screening programs.



Disclosures:


Joseph Atarere, MD, MPH¹, Mariah Malak Bilalaga, MD¹, Ramya Vasireddy, MBBS¹, Boniface Mensah, MBChB, MPH¹, Greeshma Gaddipati, MBBS¹, Simardeep Singh, MBBS¹, Ted Akhiwu, MBBS, MPH¹, Stephanie M. Woo, MD², Priyanka Kanth, MD². P1936 - Racial Differences in Pre-Cancerous Colorectal Polyps and Colorectal Cancer During Surveillance Colonoscopy Among Patients With Lynch Syndrome: Experiences From a Mid-Atlantic Healthcare System, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.