Each 1% increase in adenoma detection rates during colonoscopies results in a 3% decrease in colorectal cancer risk, according to recent research published in the New England Journal of Medicine — the largest study to date examining the link between detection rates and future risks.
Researchers at Kaiser Permanente in Oakland, Calif., examined the records of more than 314,000 colonoscopies performed by 136 experienced gastroenterologists — they had completed at least 300 colonoscopies and performed an average of 2,150 exams per year — in the health system between January 1998 and December 2010. Adenoma detection rates ranged from 7.4% to 52.5%, according to the researchers, who identified 712 patients who suffered colon cancer 6 months to 10 years after undergoing colonoscopies, including 255 patients with advanced-stage cancers and 147 patients who died from colon cancer.
Physicians with the highest adenoma detection rates discovered cancerous growths in 33% to 52% of all exams, which resulted in 0.05% of patients developing colon cancer each year. Conversely, physicians with the lowest detection rates found growths in 7% to 19% of all colonoscopies performed, resulting in 0.1% of patients developing colon cancer.
The findings show adenoma detection rates are an accurate quality metric for physicians performing colonoscopies, says Douglas A. Corley, MD, PhD, a research scientist at the Kaiser Permanente Northern California Division of Research and the study's lead author. He adds, "Given these results, to maximize the effectiveness of our screening programs, we have been providing feedback to physicians for 3 years and have been developing new methods to maximize detection rates."