Biennial PSA measurements lowered the relative risk of metastatic prostate cancer by nearly 50%.
Biennial PSA screening decreases the likelihood of being diagnosed with metastatic prostate cancer, but nearly doubles the chance of being diagnosed with prostate cancer of any type, a Swedish sudy found.
Gunnar Aus, MD, of Sahlgrens University Hospital in Göteborg, and his colleagues randomly selected 20,000 men aged 50-65 years from the Swedish Population Registry, and divided them evenly into an intervention group and control group.
After excluding those who had prostate cancer, there were 9,972 men in the intervention group (of whom 7,516 responded to an invitation to have their PSA tested every two years and 2,456 did not) and 9,973 in the control group. The investigators monitored the diagnosis of metastatic cancer in the control arm using the Swedish Cancer RegIstry.
After 10 years of follow-up, 24 cases of metastatic prostate cancer were diagnosed in the screening group (0.24%) compared with 47 cases in the controls (0.47%), which translates into a 48.9% decrease in risk, the investigators reported in European Urology (2007;51:659-664). Of the 24 cases diagnosed in the screening group, 13 occurred in the nonresponders. During the study period, 810 cases of prostate cancer were diagnosed in the screening group compared with 442 among controls.
The absolute number of cases of metastatic prostate cancer was small, the authors pointed out. The likelihood of living 10 years without being newly diagnosed with metastatic prostate cancer in the screening and controls arms was 99.76% and 99.53%, respectively, they reported.