New research indicates that PSA screening results in a long lead time (time it would take for a cancer to be diagnosed clinically in the absence of screening) and a high overdiagnosis probability (percentage of cancers detected by screening that would not have been diagnosed before death). The results of this study were published in the Journal of the National Cancer Institute.[1]

Prostate cancer is typically a disease of aging. It may persist undetected for many years without causing symptoms. In fact, most men die with prostate cancer, not from prostate cancer. Approximately 20% of men will develop prostate cancer during their lifetime, yet only 3% will actually die of the disease.

The PSA blood test is a simple blood test that measures the level of prostate-specific antigen, a protein that is normally secreted and disposed of by the prostate gland. High PSA levels may indicate the presence of prostate cancer cells or other noncancerous prostate conditions. PSA screening has long been a controversial practice because it is unclear whether the early diagnosis of prostate cancer results in decreased mortality from the disease.

In the current study, researchers used three different computer models to estimate lead times and the percentage of overdiagnosed cancers due to PSA screening from 1985-2000 among U.S. men ages 54-80. The models indicated that the estimated mean lead time ranged from 5.4-6.9 years and overdiagnosis ranged from 23- 42% of PSA-detected cancers.

Overdiagnosis is a huge concern in terms of financial costs, unnecessary treatment, debilitating side effects, and undue anxiety. Prostate cancer grows so slowly that many men end up dying from other causes before the prostate cancer poses a threat. The early diagnosis of a tumor often forces men into treatment that may not prolong their life yet can leave them with side effects such as incontinence and impotence. In addition, the long lead time leaves men living with the anxiety of cancer for a disproportionate amount of time. Overdiagnosis also carries a financial burden for patients, insurance providers, and the healthcare system. High PSA levels often lead to unnecessary biopsies and treatment.

Research is ongoing in order to sift through the confusion of this controversial issue. In the meantime patients are advised to weigh the benefits and risks of PSA screening and to make an informed decision with their physician as to the best course of action.

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