Background and aim: Because the risk of colorectal cancer has not been well examined in fecal immunochemistry test (FIT)-positive patients who previously underwent colonoscopy, this study aimed to investigate this topic.
Methods: This was a single-center, observational study of prospectively collected data in Japan. FIT-positive, average-risk patients who underwent colonoscopy were divided into groups as follows: those who never underwent colonoscopy in the past (no colonoscopy group), those with a history of colonoscopy between 6 months and 5 years (0.5- to 5-year colonoscopy group), and those with a history of colonoscopy more than 5 years ago (> 5-year colonoscopy group). We investigated the prevalence of advanced neoplasia and invasive cancer among these groups using multiple logistic regression analysis.
Results: Detection rates of advanced neoplasia in the no colonoscopy group, 0.5- to 5-year colonoscopy group, and > 5-year colonoscopy group were 14.8% (240/1626), 3.9% (13/330), and 6.9% (17/248), respectively. Detection rates of invasive cancer in each aforementioned group were 5.7% (92/1,626), 0.3% (1/330), and 1.2% (3/248), respectively. Odds ratios of advanced neoplasia in the 0.5- to 5-year colonoscopy group and > 5-year colonoscopy were 0.23 (95% confidence interval [CI]: 0.13-0.42) and 0.40 (95% CI: 0.24-0.68), respectively, in multivariate analysis. The odds ratios of invasive cancer in each aforementioned group were 0.05 (95% CI: 0.01-0.37) and 0.19 (95% CI: 0.06-0.61), respectively.
Conclusion: Re-screening with the FIT should not be recommended for at least 5 years for average-risk patients after colonoscopy without high-risk neoplasms, because the risks of colorectal cancer are low in such patients.
Keywords: cancer screening; colonoscopy; colorectal neoplasms; occult blood.
© 2018 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.