Prostate Cancer Screening (PDQ®): Screening - Health Professional Information [NCI] - Evidence of Benefit
Summary of First Four Prostate, Lung, Colorectal, and Ovarian Screening Roundsa continued...
In the screening group, 82% of men accepted at least one offer of screening. With 14 years of data, and a median follow-up of 9 years, there were 5,990 prostate cancers diagnosed in the screening group and 4,307 in the control group, corresponding to a cumulative incidence of 8.2% and 4.8%, respectively. There were 214 prostate-cancer deaths in the screening group and 326 prostate cancer deaths in the control group in the core age group. The unadjusted rate ratio for death from prostate cancer in the screening group was 0.80 (95% CI, 0.67–0.95); after adjustment for sequential testing with alpha spending due to two previous interim analyses (based on Poisson regression analysis), the rate ratio was 0.80 (95% CI, 0.65–0.98). The rates of death in the two study groups began to diverge after 7 to 8 years and continued to diverge further over time.
The absolute difference between the screening and control groups was 0.71 prostate-cancer deaths per 1,000 men. Thus, in order to prevent one prostate-cancer death, the number of men who would need to be screened would be 1,410. The additional prostate cancers diagnosed by screening resulted in an increase in cumulative incidence of 34 per 1,000 men, so that 48 additional subjects would need to be treated to prevent one death from prostate cancer. Thus, PSA-based screening reduced the rate of death from prostate cancer by 20% but was associated with a high risk of overdiagnosis.
Important information that was not reported includes the contamination rate in the control group, and the treatment administered to the prostate cancer cases by stage and by randomly assigned group. Incompleteness of data is also a concern because it appears that several of the participating countries have not yet provided data beyond the 10-year point at which the major effect appears to occur. Longer follow-up will be needed to determine the final results of this trial.
While the ERSPC demonstrated a 29% relative reduction in mortality from prostate cancer among men who were screened at 4-year intervals, there were associated harms from overdiagnosis and long-term treatment effects. Microsimulation Screening Analysis (MISCAN) was used to estimate the quality-adjusted life-years (QALYs) associated with annual PSA screening, based on results from the ERSPC trial. Health states considered in the analysis of QALYs included biopsy, cancer diagnosis, radiation therapy, radical prostatectomy, active surveillance, postrecovery period, palliative therapy and terminal illness. Adverse effects considered included overdiagnosis and various degrees of incontinence and erectile dysfunction. The model predicted that annual screening of 1,000 men aged 55 to 69 years would lead to nine fewer deaths from prostate cancer (98 men screened to prevent one prostate cancer death). Overall, 73 life-years would be gained, but QALYs gained was only 56 life-years on average with a range of -21 to 97 life-years. Screening men aged 55 to 74 years increased life-years gained but resulted in the same number of QALYs on average (56 life-years).