Lowering the current prostate-specific antigen (PSA) threshold for recommending a prostate biopsy may subject millions of men to unnecessary, potentially harmful medical procedures with no evidence that it will improve prostate cancer mortality rates, according to a new study in the August 3 issue of the Journal of the National Cancer Institute.
Currently, doctors recommend that men with an "abnormal" PSA level--a level exceeding 4.0 ng/mL--receive a prostate biopsy to test for prostate cancer. However, some men diagnosed with prostate cancer have a PSA level lower than this threshold, prompting some in the medical field to suggest lowering the cutoff to 2.5 ng/mL to possibly detect more cancer cases.
To examine the implications of this suggestion, H. Gilbert Welch, M.D., M.P.H., of the Department of Veterans Affairs Medical Center in White River Junction, Vt., and colleagues examined data from the 2001-2002 National Health and Nutrition Examination Survey for 1,308 men of 40 years of age or older with no prior history of prostate cancer, and National Cancer Institute data on the risk of prostate cancer death. Using this information, they calculated the effects of lowering the PSA cutoff to 2.5 ng/mL on men screened by a PSA test.
They found that if all US men aged 40-69 (those most likely to be screened) were tested using PSA with a 4.0 ng/mL threshold, about 1.5 million of them would have a PSA level abnormally high enough to justify a biopsy. Lowering the threshold to 2.5 ng/mL would call for an additional 1.8 million men to receive biopsies. This group of "abnormal" men would comprise 10.7% of all US men between the ages of 50 and 59, and 17% of men between the ages of 60 and 69.