Published: July 9, 2025
Recent advances in colonoscopy techniques are helping physicians detect more colon cancers while reducing complications, according to updated medical guidelines that emphasize quality indicators and improved detection methods.
William B. Evans III, M.D., gastroenterologist with Norton Gastroenterology Consultants of Louisville, presented the findings at a continuing medical education session, outlining key changes in how physicians should perform and evaluate colonoscopy procedures to maximize cancer screening effectiveness.
The most critical quality measure is the adenoma detection rate (ADR), which tracks how often physicians find and remove precancerous polyps during screening procedures. Current standards require detection rates of at least 30% for men and 20% for women, with an overall benchmark of 25%.
“The higher the ADR, the lower the risk of interval colon cancers between colonoscopies,” Dr. Evans said.
Interval cancers, which develop after a screening but before the next scheduled procedure, account for nearly 10% of all colon cancers.
Other quality indicators include reaching the cecum in at least 95% of procedures and spending a minimum of six minutes examining the colon during scope withdrawal, though some studies suggest nine minutes may be more effective.
Physicians are adopting more sophisticated systems to describe and categorize polyps they discover. The Paris Classification system helps doctors distinguish between raised polyps that grow off the colon wall and flat lesions that can be harder to detect.
The Boston Bowel Preparation Scale replaces older, less specific terminology with numerical grades from 0 to 3 for different colon segments. A total score of 6 out of 9, with all segments scoring at least 2, is required for patients to wait the full 10 years before their next screening.
Advanced imaging techniques, including narrow-band imaging, help physicians identify which polyps may contain cancer cells that have spread deeper into tissue layers. These high-risk lesions require surgical removal rather than endoscopic treatment.
New removal techniques are making procedures safer while maintaining effectiveness. Cold snare polypectomy, which doesn’t use electrical current, reduces bleeding and perforation risks to less than 1% while achieving nearly 100% complete removal rates.
For larger polyps, physicians are encouraged to use endoscopic mucosal resection rather than immediately referring patients for surgery. Studies show endoscopic removal of benign large polyps results in lower mortality, fewer complications and reduced cost, compared with surgical approaches.
“Surgery for benign polyps can result in higher mortality, morbidity and cost than endoscopic resection,” Dr. Evans said, though he acknowledged that reimbursement issues and training limitations sometimes can prevent optimal treatment.
Artificial intelligence programs are showing promise in improving polyp detection rates. A recent analysis of nearly 30,000 patients found computer-assisted systems increased detection rates by 20% and decreased miss rates by 55% without significantly extending procedure time.
Water exchange techniques, where physicians infuse water to distend the colon instead of air, also may improve detection while reducing patient discomfort during difficult procedures.
New guidelines specify follow-up intervals based on initial screening findings:
The guidelines represent collaboration between major gastroenterology societies to standardize care and improve outcomes.
Medical organizations are offering expanded training programs to help physicians implement the new techniques and classification systems. While the changes may seem complex initially, according to Dr. Evans, they become routine with practice.
“These classification systems have been proven to improve our ability to perform better quality colonoscopy,” he said. “Once you start using these regularly, they become automatic.”
The emphasis on quality metrics reflects growing recognition that not all colonoscopies provide equal cancer protection. Studies have linked low-performing physicians to higher rates of interval cancers, particularly for right-sided colon lesions that can be more difficult to detect.
Implementation of these guidelines could significantly improve the effectiveness of colon cancer screening programs, which have contributed to declining death rates from the disease over the past two decades.