U of M Study: More Prostate Screening Not Equal to Fewer Deaths

More prostate screening leads to more diagnoses of prostate cancer, but doesn't translate to fewer deaths, according to new research at the University of Minnesota.

Half of the 76,693 men in the study were randomly assigned to be offered annual screening with prostate-specific antigen tests for six rounds and digital rectal physical exams the first four rounds.
The other 38,350 men were randomly assigned to usual-care and did not receive recommendations for or against annual prostate cancer screening.

“What this report tells us is that the short-term benefits of prostate cancer screening, using present methods, do not result in the reductions in death that we had hoped,” said Timothy R. Church, Ph.D., professor in the University of Minnesota’s School of Public Health and cancer researcher with the University’s Masonic Cancer Center.

The U.S. Preventive Services Task Force, whose recommendations are considered the gold standard for clinical preventive services, recently concluded that there is insufficient evidence to assess the balance of benefits and harms for prostate cancer screening in men younger than age 75 and recommended against prostate cancer screening in men age 75 and older.

“It is possible that prostate cancer screening may produce longer-term benefits, and we will continue to monitor men in this study with the hope that we eventually will see reduced death from this disease,” Church said. “In the meantime, it is important to remember that men differ in their risks for prostate cancer based on their family and personal history. Those men who are concerned about their prostate health should consult with their physicians about the best way to proceed.”

Of the men in the group who were offered annual screening, 85 percent had PSA tests and 86 percent had DREs. Men in the screening group were referred to their physician or health care provider for follow-up testing for prostate cancer if their PSA level was greater than 4.0 nanograms per milliliter (ng/mL) or if DRE found an abnormality.

Men in the usual-care group sometimes had these tests as well, due to the growing public acceptance of such screening. Screening by PSA in this usual-care group increased from 40 percent at the beginning of the study to 52 percent of men by the last screening year, and screening with DRE ranged from 41 percent initially to 46 percent by the last screening year.

The National Cancer Institute (NCI) began the PLCO trial in 1992 to provide answers about the effectiveness of prostate, lung, colorectal, and ovarian cancer screening tests in reducing deaths from these cancers. Christine Berg, M.D., is the NCI leader of the PLCO trial and the senior author on this report on prostate cancer screening.

The data are being made public now because the trial’s Data and Safety Monitoring Board, an independent review committee that meets every six months, saw a continuing lack of evidence that screening reduces death due to prostate cancer as well as clear evidence that screening causes men to be treated unnecessarily.

The report is published in the New England Journal of Medicine.