CHICAGO — Repeating a flexible sigmoidoscopy at 5 years instead of 3 years after an initial negative exam increases the risk of finding a cancer or advanced adenoma by 70%.
Men are particularly at risk when they delay the follow-up, Dr. Robert Schoen said at the annual Digestive Disease Week. “Not only did men have more neoplasias than women at the 5-year exam, but, when we compared the 3- and 5-year exams, the increase in yield was significantly greater in men than in women.”
The findings were seen in a subanalysis of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Initially, the trial protocol called for repeat flexible sigmoidoscopy 3 years after an initial negative exam. In 1998, the protocol changed to a 5-year follow-up period, said Dr. Schoen of the University of Pittsburgh.
The analysis included two cohorts: those whose repeat screenings took place after 3 years (9,000) and those whose repeat screenings took place after 5 years (24,000). None of the subjects had a polyp identified on their initial exam.
Overall, he said, significantly more 5-year exams were positive for a neoplasm (21% vs. 14%) than were 3-year exams. The crude number of cancers identified was not significantly different between the cohorts, but the number of cancers or advanced adenomas was (12/1,000 vs. 9/1,000 subjects). The crude rate of cancer or any adenoma also was significantly higher in the 5-year group (49/1,000 vs. 34/1,000).
In both cohorts, men were significantly more likely than women to have a neoplasm identified. But in a comparison of the 3- and 5-year exams, men also had a significantly higher change in the yield with the different follow-up times. (See chart.)
After controlling for age, gender, and history of a colon procedure at least 3 years before enrollment, the investigators found delaying the repeat exam to 5 years significantly increased the yield of a cancer or any adenoma by 70% and of cancer or an advanced adenoma by 47%.
Dr. Schoen had no financial disclosures relevant to the study.
Men were significantly more likely than women to have a neoplasm identified.
Source DR. SCHOEN
Source ELSEVIER GLOBAL MEDICAL NEWS