Time to Colonoscopy and Risk of Colorectal Cancer in Patients With Positive Results From Fecal Immunochemical Tests

Abstract

In patients with positive results from a fecal immunochemical test (FIT), failure to receive a timely follow-up colonoscopy may be associated with higher risks of colorectal cancer (CRC) and advanced-stage CRC. We evaluated the prevalence of any CRC and advanced-stage CRC associated with delays in follow-up colonoscopies for patients with positive results from a FIT. We collected data from 39,346 patients (age, 50-69 years) who participated in the Taiwanese Nationwide Screening Program from 2004 through 2012 and had completed a colonoscopy more than 1 month after a positive result from a FIT. Risks of any CRC and advanced-stage CRC (stage III-IV) were evaluated using logistic regression models and results expressed as adjusted odds ratios (aORs) and corresponding 95% CIs. In our cohort, 2003 patients received a diagnosis of any CRC and 445 patients were found to have advanced-stage disease. Compared with colonoscopy within 1-3 months (cases per 1000 patients: 50 for any CRC and 11 for advanced-stage disease), risks were significantly higher when colonoscopy was delayed by more than 6 months for any CRC (aOR, 1.31; 95% CI, 1.04-1.64; 68 cases per 1000 patients) and advanced-stage disease (aOR, 2.09; 95% CI, 1.43-3.06; 24 cases per 1000 patients). The risks continuously increased when colonoscopy was delayed by more than 12 months for any CRC (aOR, 2.17; 95% CI, 1.44-3.26; 98 cases per 1000 patients) and advanced-stage disease (aOR, 2.84; 95% CI, 1.43-5.64; 31 cases per 1000 patients). There were no significant differences for colonoscopy follow up at 3-6 months for risk of any CRC (aOR, 0.98; 95% CI, 0.86-1.12; 49 cases per 1000 patients) or advanced-stage disease (aOR, 0.95; 95% CI, 0.72-1.25; 10 cases per 1000 patients). In an analysis of data from the Taiwanese Nationwide Screening Program, we found that among patients with positive results from a FIT, risks of CRC and advanced-stage disease increase with time. These findings indicate the importance of timely colonoscopy after a positive result from a FIT.