Many doctors don’t. A new study published this week in the Annals of Internal Medicine has found that cancer screening statistics are not well understood by most primary care physicians (PCPs) in this country, which may influence how physicians discuss screening with their patients or how they teach trainees.

Researchers found that 76% of PCPs mistakenly believe that better survival rates with cancer screening proves that screening saves lives. And almost half (47%) of the physicians mistakenly indicated they believed that increased cancer detection in screened populations also saves lives. Both statistics are often misused by PCPs to promote screening.

The fact is that screening automatically increases survival rates because when cancer is detected prior to onset of symptoms, the patient will live longer — regardless of whether anything is done to treat them. Few of the more than 400 physicians in the study who took the internet survey correctly recognized that only reduced mortality in a randomized trial constitutes evidence of the benefit of screening.

“Misunderstanding of statistics has been fueling a great deal of screening,” Dr. Otis Brawley, chief medical officer of the American Cancer Society told Reuters Health. “Unfortunately we have all been taught that the way to deal with cancer is to find it early. As we have learned more and more about cancer, we are starting to find that that’s not true.”

For a number of tests, there is not only no evidence of benefit, but there is evidence of potential harm. One such controversial practice is prostate cancer screening, which has become widespread.

There is a now a push for education in screening statistics (especially cancer screening) to extend beyond doctors to the public.

Physician’s Weekly wants to know… Is more screening better, regardless of screening statistics? Due to the strong influence of the media, should educational efforts extend to journalists?