Prostate cancer mortality was reduced almost by half over a 14-year period in a randomized patient population following prostate-specific antigen (PSA) screening, said the results of a study published online June 30 in the Lancet Oncology.
The extent of benefits and harms associated with prostate cancer screening remains under continuous debate, explained Jonas Hugosson, MD, from the University of Gothenburg in Sweden, and colleagues. The researchers sought to determine whether the benefits of prostate-cancer screening compared favorably to other cancer screening programs.
Noting that screening men for the presence of PSA can decrease the risk of death, as increased concentrations of this antigen indicate higher risk, the authors designed a randomized controlled trial to include 20,000 men born between 1930 and 1944, living in Gothenburg. Half of the men were placed in either the intervention arm (screening group), who were invited for PSA testing every two years, and the other half were placed in a control group not invited for screening. Men in the screening group with raised PSA concentrations were offered additional tests such as digital rectal examinations and prostate biopsies.
In each cohort, 48 men were excluded due to death or immigration before the randomization date or prevalent prostate cancer. Primary endpoints for the study included prostate-cancer specific mortality, analyzed according to the intention-to-screen principle, explained the authors.
For the 9,952 men in the screening cohort, 76 percent underwent screening at least once. At the 14-year follow up, the researchers found that 1,138 men in the screening group and 718 in the control group were diagnosed with prostate cancer, signifying a cumulative prostate-cancer incidence of 12.7 percent in the screening group and 8.2 percent in the control group.
Additionally, Hugosson and colleagues observed an absolute cumulative risk reduction of death from prostate cancer of 0.4 percent, from 0.9 percent in the control group, to 0.5 percent in the screening group. The rate ratio for death from prostate cancer was 0.56 percent in the screening group compared with the control group and the rate ratio of death from prostate cancer for the screening cohort compared with the control group was 0.44 percent.
“Overall, 293 men needed to be invited for screening and 12 diagnosed to prevent one prostate cancer death,” determined the researchers.
The findings of the study suggested that a PSA-based screening program is acceptable for men 50 years and older and the benefit of prostate-cancer screening compares favorably to other cancer screening programs; however, “the risk of over-diagnosis is substantial and the number needed to treat is at least as high as in breast cancer screening programs,” concluded Hugosson.