Many prostate cancer patients and advocates may be less than enthused by data published this week in the New England Journal of Medicine, and based on 11-year follow-up of patients in the European Randomized Study of Screening for Prostate Cancer (ERSPC).
The study managers for the ERSPC have previously reported a 29 percent reduction in prostate cancer-specific mortality among the men in this trial who underwent PSA-based screening for risk of prostate cancer compared to those who had no screening. This most recent study was carried out to assess the degree to which “harms” to quality of life resulting from over-diagnosis and over-treatment can be considered to counterbalance the previously reported benefit.
Heijnsdijk et al. applied a process known as microsimulation screening analysis (MISCAN) to estimate the number of prostate cancers, treatments, deaths, and quality-adjusted life-years (QALYs) gained after the introduction of PSA screening. It should be remembered by readers that this study is based on an exercise of complex modeling skills requiring many assumptions, and so all results are open to considerable question based on assessments of the accuracy of the modeling process.
Having said that, here are the core findings reported by Heijnsdijk and her colleagues:
- For each 1,000 men screened, annual PSA-based screening of men aged between 55 and 69 years of age would result in
- 9 fewer deaths from prostate cancer (a 28 percent reduction in prostate cancer-specific mortality)
- 14 fewer men requiring palliative therapy for prostate cancer (a 35 percent reduction in the need for palliative care)
- A total gain of 73 life-years (i.e., 8.4 years for each prostate cancer-specific death avoided)
- A total gain of 56 quality-adjusted life years (QALYs), with a range of –21 to 97 QALYs
- To prevent a single prostate cancer-specific death
- 98 men would need to be screened
- 5 cancers would need to be detected
- Annual screening of all men aged between 55 and 69 years of age would result in
- An increase in the number of life-years gained (from 73 to 82 per 1,000 men screened)
- No change in the number of QALYs gained (still 56 per 1,000 men screened)
Heijnsdijk and her colleagues conclude that the “benefit of PSA screening was diminished by loss of QALYs owing to postdiagnosis long-term effects.” They are, however, very careful to note their belief that longer follow-up data from both the ERSPC study itself and from appropriate quality-of-life analyses are essential before it would be possible to make any “universal recommendations” about the value of annual PSA-based screening.
The “New” Prostate Cancer InfoLink has not seen the full text of this article, and — even if we had — we do not feel competent to make any reasonable assessment of the validity of the modeling process used by Heijnsdijk et al. We have also not seen the full text of the editorial (by Sox) in the New England Journal of Medicine addressing this article. We will see if we can get copies of the full text of the article and the editorial in the near future. At this point in time we are only able to report what is stated in the abstract of the article.
Other commentaries on this study are already widely available (on HealthDay, on Medscape, on Reuters, on MedPage Today, and on WebMD). Some readers may want to review all of these commentaries. It is apparent from at least some of these commentaries that the editorialist in the New England Journal beleives that these data further justify the importance of discussion between individual patients and their doctors about the risks and benefits of PSA testing before administration of any such test.