Screening intervals for colonic neoplasia.

Surveillance examinations after detection of an adenoma are one of the largest contributors to the cost of colorectal cancer screening. Screening colonoscopy, beginning at the age of 50 years, is increasing in frequency and becoming part of the zeitgeist. Given the high rate of adenomatous polyp detection on colonoscopy, the amount of time spent and costs consumed by surveillance are likely to grow to significant levels in the coming years. Guidelines for surveillance examinations vary across specialty organizations. Individuals with advanced adenomas are at increased risk for recurrent advanced adenomas. The impact of multiple nonadvanced adenomas or a single nonadvanced adenoma on subsequent risk of an advanced adenoma or cancer is less clear. Recommended surveillance after colorectal cancer has greater consensus, but concerns remain. Studies that predict the need and the needed timing of surveillance remain an important research priority.