Annual Fecal Occult Blood Testing Can Be Safely Suspended for Up To 5 Years After a Negative Colonoscopy in Asymptomatic Average-Risk Patients

Abstract

Background: In clinical practice, physicians often continue to perform annual fecal occult blood testing (FOBT) in patients who have had a recent negative colonoscopy. The Centers for Disease Control and Prevention (CDC) discourages this practice because it increases the likelihood of false positive results, and they recommend suspending annual FOBT for 5-10 years after a negative total colon exam. However, these recommendations were based on “expert” opinion. The aim of this prospective study was to determine the proportion of patients with a positive FOBT who had adenomas and cancers on colonoscopy stratified according to duration of time since the last negative colonoscopy. Methods: 1,119 asymptomatic average-risk patients ≥ 50 years of age who were referred for colonoscopy to evaluate a positive FOBT were prospectively identified. A detailed medical history was obtained from all patients prior to colonoscopy, and subjects were stratified by the duration of time since last colonoscopy (never had a colonoscopy, negative colonoscopy >10 years, 5-10 years, or >5 years). The proportion of patients in each category with adenomas of any size, adenomas = 10 mm, advanced neoplasms (adenomas = 10 mm or any adenoma, regardless of size, with villous histology, high-grade dysplasia, or cancer), and cancers was assessed. Results: The mean age (68.9 ± 9.6 years), sex (95.2% male), and race (48.1% white, 32.1% black, 15.6% Hispanic, and 4.2% other) did not differ between the 4 groups. Colonoscopy was complete to the cecum in 97.1% of patients and was similar in all 4 groups (P = 0.61). Overall, adenomas of any size were detected in 42.8% of patients, adenomas =10 mm in 14.7%, advanced neoplasms in 20.7%, and cancers in 7.3%. Conclusions: In asymptomatic average-risk patients who have had a negative colonoscopy within the last 5 years, the prevalence of adenomas is low and no patient was diagnosed with cancer. Although these findings support the CDC recommendations to suspend annual FOBT for up to 5 years after a negative total colon examination, suspending FOBT for up to 10 years may miss potentially curable lesions.