Adenoma Detection Rates Affect Colon Cancer Risk and Mortality

Routine colonoscopies play a vital role in colon cancer prevention, but experts say it isn’t just the test itself that matters – it’s the quality of the examination.

Adenoma detection rate (ADR) is a numeric value that represents the number of people over 50 who undergo a complete screening colonoscopy and have a precancerous polyp, or adenoma, detected. For years, ADR has been accepted as a valuable measure of colonoscopy quality, but new research suggests that ADRs may be a key indicator in colon cancer incidence and survival outcomes.

Reinier G.S. Meester, M.Sc., of Erasmus MC University Medical Center in Rotterdam, the Netherlands, and his team of researchers analyzed information from more than 57,000 screening colonoscopies and found evidence that higher ADRs may lower lifetime risk of colorectal cancer incidence and death by up to 50 or 60 percent. To perform their study, Meester and colleagues compared unscreened patients to patients who had been screened by physicians with ADRs ranging from 7.4 percent to 53 percent. ADRs were classified into five groups, called quintiles, with the lowest ADRs in quintile 1 and highest ADRs in quintile 5.

The results of their microsimulation model showed that unscreened patients had a lifetime colorectal cancer risk of 34.2 per 1,000 and a lifetime colorectal mortality risk of 13.4 per 1,000. Patients with physicians in quintile 1 had an incidence risk of 26.6 per 1,000, while patients with physicians in quintile 5 had an incidence risk of 12.5 per 1,000. Estimates showed that the risk of incidence and mortality decreased by 11 to 13 percent for every 5-point increase in ADR, an overall difference of 53 to 60 percent among the five quintiles.

The study authors say more research is needed to determine why ADRs vary and whether increasing ADRs will improve patient outcomes.

The study can be found in the June 16 issue of JAMA (Source: News Medical).

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