LAUSR

INTRODUCTION Surveillance colonoscopy 1-year after surgical resection for patients with stages I-III colorectal cancer (CRC) is suboptimal and data on factors associated with lack of adherence are limited. Using surveillance colonoscopy data from Washington state, we aimed to determine the patient, clinic, and geographical factors associated with adherence. METHODS Using administrative insurance claims linked to Washington (WA) cancer registry data we conducted a retrospective cohort study of adult patients diagnosed with stage I-III CRC between 2011 and 2018 with continuous insurance for at least 18 months after diagnosis. We determined the adherence rate to 1-year surveillance colonoscopy and conducted logistic regression analysis to identify factors associated with completion. RESULTS Of 4,481 stage I-III CRC patients identified, 55.8% completed a 1-year surveillance colonoscopy. The median time to colonoscopy completion was 370 days. On multivariate analysis, older age, higher stage CRC, Medicare insurance or multiple insurance carriers, higher Charlson Comorbidity Index score and living without a partner were significantly associated with decreased adherence to 1-year surveillance colonoscopy. Among 29 eligible clinics, 51% (n=15) reported lower than expected surveillance colonoscopy rates based on patient mix. CONCLUSION Surveillance colonoscopy 1-year after surgical resection is sub-optimal in WA state. Patient and clinic factors, but not geographic factors (Area Deprivation Index), were significantly associated with surveillance colonoscopy completion. This data will inform the development of patient and clinic level interventions to address an important quality of care issue across Washington.