Background
Prostate cancer is one of the leading causes of death from malignant disease among men in the developed world.
One strategy to decrease the risk of death from this disease is screening with prostate-specific antigen (PSA); however, the extent of benefit and harm with such screening is under continuous debate.
Aim
To assess the benefits and harms of PSA screening from the Goteborg randomised prostate-cancer screening trial.
Methods
In December 1994, 20,000 men born between 1930 and 1944, randomly sampled from the population register, were randomised by computer in a 1:1 ratio to either a screening group invited for PSA testing every 2 years (n=10,000) or to a control group not invited (n=10,000).
Men in the screening group were invited up to the upper age limit (median 69, range 67-71 years) and only men with raised PSA concentrations were offered additional tests such as digital rectal examination and prostate biopsies.
The primary endpoint was prostate-cancer specific mortality, analysed according to the intention-to-screen principle. The study is ongoing, with men who have not reached the upper age limit invited for PSA testing.
Results
In each group, 48 men were excluded because of death or emigration before the randomisation date or prevalent prostate cancer. In men randomised to screening, 7578 (76%) of 9952 attended at least once.
During a median follow-up of 14 years, 1138 men in the screening group and 718 in the control group were diagnosed with prostate cancer, resulting in a cumulative prostate-cancer incidence of 12.7% in the screening group and 8.2% in the control group (hazard ratio 1.64; 95% CI 1.50-1.80; p<0.0001).
The absolute cumulative risk reduction of death from prostate cancer at 14 years was 0.40% (95% CI 0.17-0.64), from 0.90% in the control group to 0.50% in the screening group.
The rate ratio for death from prostate cancer was 0.56 (95% CI 0.39-0.82; p=0.002) in the screening compared with the control group.
The rate ratio of death from prostate cancer for attendees (those invited for screening who attended at least once) compared with the control group was 0.44 (95% CI 0.28-0.68; p=0.0002).
Overall, 293 (95% CI 177-799) men needed to be invited for screening and 12 to be diagnosed to prevent one prostate cancer death.
Conclusion
This study shows that prostate cancer mortality was reduced by almost half over 14 years. However, the risk of over-diagnosis is substantial and the number needed to treat is at least as high as in breast-cancer screening programmes.
The benefit of prostate-cancer screening compares favourably to other cancer screening programs.
