At the same time as the PLCO trial was being carried out in the USA, an analogous but not strictly comparable trial was being carried out in Europe: the European Randomized Screening Study for Prostate Cancer, also known as the ERSPC trial.
The report on this trial, by Schröder et al., appeared in the same issue of the New England Journal of Medicine as the report on the PLCO trial. This was most certainly not random chance.
As with the PLCO trial, the primary goal of this trial was to determine whether regular testing (“screening”) for prostate cancer led to a reduction in deaths from this disease. However, the structure of this trial was very different to that of the PLCO trial. Because this study involved patients from seven different European countries, and there were differences in the study protocol from country to country, this is an extremely difficult study from which to interpret results with a high degree of confidence. However …
The investigators identified 182,000 men aged between 50 and 74 years of age from the seven different European countries starting in “the early 1990s”. (The precise dates that different countries started to enroll patients into this trial varied.) As in the PLCO trial, these men were randomly assigned to a screening group or to a control group. However, there the comparison ends. In the ERSPC study, men in the screening group received a PSA test at an average of once every 4 years and the men in the control group supposedly did not receive PSA tests at all. The 162,243 men included in this particular analysis had a predefined core age of between 55 and 69 years. The primary outcome of the study was the rate of death from prostate cancer, and the mortality follow-up was the same for both groups of patients, ending on the last day of December 2006.
The results of the ERSPC study are as follows:
- 82 percent of men assigned to the screening group accepted at least one offer of screening.
- The cumulative incidence of prostate cancer in the screening group was 8.2 percent at a median follow-up of 9 years.
- The cumulative incidence of prostate cancer in the control group was 4.8 percent over the same median time frame.
- The rate of death in the screening group as compared to the control group was 0.80 (i.e., 20 percent lower).
- The absolute difference in risk of death in the screening group as compared to the control group was 0.71.
- These data imply that, to prevent a single death from prostate cancer, 1,410 men would need to be screened and 48 additional cases of prostate cancer would need to be treated relative to the men in the unscreened population.
- Looking only at those men who were tested during the first round of screening, the rate of death in the screening group as compared to the control group was 0.73.
In this study the authors concluded as follows: “PSA-based screening reduced the rate of death from prostate cancer by 20 percent but was associated with a high degree of overdiagnosis.”
The other conclusion that The “New” Prostate Cancer InfoLink thinks can clearly be drawn from this study, when taken in combination with the PLCO study, is that a 10-year follow-up is insufficient to determine whether prostate cancer screening has an overall mortality benefit. The 20 percent benefit demonstrated by the ERSPC study at 9 years is only border-line significant (P = 0.04). Thus, these two large, randomized studies of prostate cancer screening, involving men between 50 and 74 years of age, have not been able to offer a definitive recommendation regarding the value of prostate cancer screening that can be generally applied to most men.
THE "NEW" PROSTATE CANCER INFOLINK 