What explains the differences between centres in the European screening trial? A simulation study

Estimating the rate of overdiagnosis with prostate cancer screening: evidence from the Finnish component of the European Randomized Study of Screening for Prostate Cancer

PURPOSE

Screening for prostate cancer may have limited impact on decreasing prostate cancer-related mortality. A major disadvantage is overdiagnosis, whereby lesions are identified that would not have become evident during the man's lifetime if screening had not taken place. The present study aims to estimate the rate of overdiagnosis using Finnish data from the European randomized trial of prostate cancer screening.

METHODS

We used data from 80,149 men randomized to a screening or a control group, distinguishing four birth cohorts. We used the "catch-up method" to identify when the difference in the cumulative incidence of prostate cancer between the screening and control groups had stabilized, implying that the screening has no further effect. We define the overdiagnosis rate to be the relative excess cumulative incidence in the screened group at that point. As an independent method, we also examined the diagnosis rates of T1c tumors as an indicator of early tumors detected by PSA.

RESULTS

The estimates of overdiagnosis rates from the catch-up method using the full period of available follow-up ranged between cohorts from 2.3% to 15.4%, and the T1c analysis gave very similar results.

CONCLUSION

Some overdiagnosis has occurred, but there is uncertainty about its extent. A long follow-up is required to demonstrate the full impact of screening. We evaluated the overdiagnosis rates at a population level, associated with being offered screening, taking account of contamination (screening among the controls). The overall evaluation of screening should incorporate mortality benefit, cost-effectiveness, and quality of life.

Long-term health-related quality of life among men with prostate cancer in the Finnish randomized study of screening for prostate cancer

Background

The long‐term health‐related quality of life (HRQOL) impacts of PCa screening have not been adequately evaluated. We aimed to compare the generic and disease‐specific health‐related quality of life (HRQOL) among men with prostate cancer in the screening arm with the control arm of the PSA‐based prostate cancer screening trial in up to 15 years of follow‐up.

Materials and methods

This study was conducted within population‐based Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC). During 1996‐1999 80,458 men were randomized to the serum prostate‐specific antigen (PSA) screening arm (SA, N = 32 000) and the control arm (CA, N = 48 458). Men in the screening arm were screened at 4‐year intervals until 2007. HRQOL questionnaires were delivered to newly diagnosed prostate cancer patients in the screening and control arm 1996‐2006 (N = 5128) at the time of diagnosis (baseline), at 3‐month, 12‐month and 5, 10, and 15‐year follow‐up. Validated UCLA Prostate Cancer Index (UCLA‐PCI) and RAND 36‐Item Health Survey were used for HRQOL assessment. The data were analyzed with a random effects model for repeated measures.

Results

At baseline, men with prostate cancer in the screening arm reported better Sexual Function, as well as less Sexual and Urinary Bother. Long‐term follow‐up revealed slightly higher HRQOL scores in the screening arm in prostate cancer specific measures at 10‐year post diagnosis, but the differences were statistically significant only in Urinary Bother (UCLA‐PCI score 77.9; 95% CI 75.2 to 80.5 vs. 70.9; 95% CI 66.8 to 74.9 P = .005). The generic HRQOL scores were comparable between the trial arms. The overall differences in disease‐specific or generic HRQOL scores by trial arm did not vary during the follow‐up.

Conclusion

No major differences were observed in HRQOL in men with prostate cancer between the prostate cancer screening and control arms during five to 15‐year follow‐up.

Prostate cancer screening: what can we learn from randomised trials?

In this article, the principle of randomised trials are first described and then prostate cancer screening trials published to date are evaluated based on these principles. A summary of the randomised prostate cancer screening is provided. The conclusion that can be made from the results of the screening trials, as well as limitations of the evidence and open questions are outlined in the end.