Retrospective review of the first three years of a pilot colorectal cancer screening program in the Dominican Republic.

Abstract

e13630 Background: There are no national colorectal cancer (CRC) screening guidelines in the Dominican Republic (DR) and CRC screening is not routinely performed. In 2021, a primary care clinic in Santo Domingo, DR initiated a pilot CRC screening program using fecal immunochemical tests (FIT). This is a retrospective review of the first three years. Methods: We performed a retrospective cohort study of adults > 40 years old undergoing FIT testing (N = 3,696), categorized as asymptomatic (N = 2,886) or symptomatic (N = 810). Patients with positive FIT were referred for colonoscopy. We assessed FIT positivity, colonoscopy completion, adenoma detection, and FIT performance for high-risk lesions (invasive CRC or high-risk adenoma) among colonoscopy completers. Multivariable logistic regression evaluated predictors of colonoscopy completion among asymptomatic patients and predictors of adenoma detection among colonoscopy completers adjusted for symptoms. Results: Overall, 234/3,696 (6.3%) FIT tests were positive (asymptomatic: 4.4%, symptomatic 13.1%) and 10.4% of patients underwent a colonoscopy (asymptomatic 6.9%, symptomatic 23.1%). Among FIT-positive patients, 27.8% completed colonoscopy (asymptomatic 23%, symptomatic 37.7%). Among asymptomatic colonoscopy completers (n = 198), adenoma detection was higher in FIT-positive versus FIT-negative patients (31.0% versus 15.4%, p = 0.041). FIT performance for high-risk lesions showed high negative predictive value (NPV) in both cohorts (asymptomatic NPV 99.4%, symptomatic NPV 94.6%) with low positive predictive value (PPV) (asymptomatic PPV 10.3%, symptomatic PPV 17.5%) [Table 1]. Among asymptomatic patients, FIT positivity was independently associated with colonoscopy completion after adjustment for age and sex (aOR 4.27, 95% CI 2.73-6.67, p < 0.001). Among colonoscopy completers (N = 385, 70 events), FIT positivity was not independently associated with adenoma detection after adjusting for symptoms (aOR 1.46, 95% CI 0.77-2.75, p = 0.244). Among FIT-positive patients (N = 234), colonoscopy completion was associated with any alarm symptom (aOR 3.08, 95% CI 1.67-5.67; p = 0.0003) and alcohol use (aOR 2.74, 95% CI 1.34-5.60; p = 0.0056). Conclusions: Colonoscopy completion after FIT positivity was low, particularly among asymptomatic patients. FIT positivity was associated with adenoma detection in asymptomatic patients and FIT demonstrated high NPV for high-risk lesions. Improving linkage to colonoscopy after positive FIT may increase CRC prevention and early detection in this low-resource setting. FIT performance for high-risk lesions among patients completing colonoscopy. Cohort True Positive (TP) False positive (FP) False negative (FN) True negative (TN) Sensitivity (%) Specificity (%) PPV (%) NPV (%) Asymptomatic (n=198) 3 26 1 168 75.0 86.6 10.3 99.4 Symptomatic (n=187) 7 33 8 139 46.7 80.8 17.5 94.6