Adenoma detection rate predicted risk for interval colorectal cancer after screening colonoscopy

An endoscopist’s rate of adenoma detection was an independent predictor of risk for developing interval colorectal cancer, researchers conducting a study in Poland concluded.

“The risk was significantly higher among subjects who underwent colonoscopies that were performed by endoscopists with an adenoma detection rate of less than 20% than among subjects examined by endoscopists with a detection rate of 20% or more,” researchers wrote. “A second widely recommended quality indicator, the cecal intubation rate, was not associated with the risk of interval cancer.”

Researchers collected data from 186 endoscopists who performed colonoscopy-based colorectal-cancer screening exams on 45,026 people. There were 42 interval colorectal cancers detected during a follow-up of 188,788 person-years. Most of the cancers discovered (83.3%) occurred in patients with no family history of colorectal cancer, and 92.9% of cancers were found in those in whom no adenomas had been identified during screening examination.

The researchers found that an individual detection rate of less than 20% was significantly associated with an increased risk for interval colorectal cancer. The HRs increased when the adenoma detection rate was less than 11% (HR=10.94; 95% CI, 1.37-87.01); when the rate was 11% to 14.9% (HR=10.75; 95% CI, 1.36-85.06); and when the rate was 15% to 19.9% (HR=12.5; 95% CI, 1.51-103.43).

Additionally, researchers also found age to be an independent predictor. Individuals aged 60 to 66 years had 19 cancers (HR=13.35; 95% CI, 1.69-105.65) compared with only one cancer discovered in those aged 40 to 49 years.

Kaminski MF. N Engl J Med. 2010; 362:1795-1803.