In a 20 year follow up study screening for prostate cancer was found to have no effect on mortality, reports a Swedish study in the British Medical Journal.

Neither the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial or the European Randomized Study of Screening for Prostate Cancer (ERSPC) have shown unequivocal benefit from prostate specific antigen screening. In 1987 a randomised controlled trial on screening for prostate cancer was started in Norrköping, Sweden, by Gabriel Sandblom and colleagues from the Department of Urology at Norrköping to determine whether screening for prostate cancer reduces prostate specific mortality.

In the study 9026 men, aged between 50 and 69 years, who had been identified in the 1987 National Population Register were randomly allocated to be screened for prostate cancer by including every sixth man from a list of birth dates. Altogether 1494 men were randomly allocated to screening with the remaining 7532 men constituting the control group. For the first two occasions screening was undertaken by digital rectal examination, while for the last occasion it was combined with prostate specific antigen testing.

Results showed that 85 cases of prostate cancer (5.7%) were diagnosed in the screened group and 292 (3.9%) in the control group. The prostate specific mortality was 30/85 (35%) for men with prostate cancer diagnosed in the screening group and 130/292 (45%) for men with prostate cancer diagnosed in the control group. The overall mortality for men with prostate cancer was 69/85 (81%) in the screening group and 252/292 (86%) in the group. The median cancer specific survival was 201 months in the screened group versus 133 months in the control group. The long rank test did not show a significantly longer prostate cancer survival (P=0.065) or overall survival (P=0.14) when the screening group was compared to the control group.

"In this randomised controlled trial, screening for prostate cancer did not seem to have a significant effect on mortality from prostate cancer after 20 years of follow-up," conclude the authors.

The incidence of prostate cancer, they add, was higher in the screened group, most probably due to the detection of a larger number of indolent tumours that did not reduce prostate cancer specific survival or overall survival. "The risk for over detection and overtreatment in the screening group is considerable," they write.

The policy implications of the study, they add, are that before undergoing prostate cancer testing, asymptomatic men should be informed about the potential hazards of treatment with curative intent in case prostate cancer is diagnosed. "These include erectile dysfunction, urinary incontinence, and bowel symptoms. The discomfort associated with prostate biopsy and the psychological effects of false positive results should also be considered," write the authors, adding that the next goal should be to find ways of discriminating indolent tumours from high risk tumours and to find less aggressive treatments for indolent tumours.

Article: Sandbloom G, Varenhorst E, Rosell J et al. Randomised prostate cancer screening trial: 20 years follow-up. BMJ 2011; 342: d1539.