Do physicians understand cancer screening statistics? A national survey of primary care physicians in the United States by Odette Wegworth, published in the March 6, 2012 issue of the Annuals of Internal Medicine, found, “Most primary care physicians mistakenly interpreted improved survival and increased detection with screening as evidence that screening saves lives. Few correctly recognized that only reduced mortality in a randomized trial constitutes evidence of the benefit of screening.” Primary care physicians were more enthusiastic about the screening test supported by irrelevant evidence (5-year survival increased from 68% to 99%) than about the test supported by relevant evidence (cancer mortality reduced from 2 to 1.6 in 1000 persons). (Screening is performed by early detection tests, like mammograms to find breast cancer and PSA tests for prostate cancer. Comments: Survival statistics are susceptible to lead-time and over-diagnosis biases. While your doctor should know this basic information, most don’t; and you and your family will pay dearly for his or her ignorance. Lead-time bias occurs when disease is found earlier, but the day of death remains the same. For example, if a person is destined to die in June of 2017 of cancer, and the cancer is found in June of 2016, then the person would have lived for only a year knowing about the cancer. However, if aggressive testing is used and by “earlier detection,” the cancer is found in June of 2012, then the person lived much longer aware of the cancer (for five years), but he/she still dies the same day. If cure is defined as “living for five years,” then, in this example, the person was cured by early detection, but still died the same day. The entire newsletter from this doctor (John McDougall) can be found here: http://www.drmcdougall.com/misc/2012nl/mar/120300.htm (Click on March 2012 & click on MORE & scroll down to doctors, mammograms, PSA testing) Any MD's here care to comment?