PSA Testing Reduces Mortality But Not Yet Time for Population Screening
Prostate cancer screening reduces mortality but remains overshadowed by risk of overdiagnosis and overtreatment
- Date: 07 Aug 2014
- Author: Lynda Williams, Senior medwireNews Reporter
- Topic: Cancer Aetiology, Epidemiology, Prevention / Prostate Cancer
medwireNews: The results of the European Randomised study of Screening for Prostate Cancer (ERSPC) show a significant reduction in the risk of mortality for men who undergo prostate-specific Antigen (PSA) testing compared with those who do not.
But the authors emphasise that the high rate of associated overdiagnosis and overtreatment means they must “conclude that the time for population-based screening has not arrived”.
Nevertheless, Fritz Schröder, from Erasmus University Medical Center in Rotterdam, the Netherlands, and co-authors say that, “early diagnosis cannot be refused to men who are well informed and request to be tested.”
They now recommend that future studies should focus on ways to improve prostate cancer diagnosis, such as the use of multiparametric magnetic resonance imaging to differentiate patients with aggressive prostate cancer from those without clinically significant disease.
Over 13 years of follow-up, 7408 cases of prostate cancer were identified in 72,891 men from eight European countries, aged 55 to 69 years, who were randomly assigned to undergo PSA testing and 6107 cases were identified in 89,352 controls who received no intervention.
This gave a rate ratio of prostate cancer incidence of 1.91 after 9 years, 1.66 after 11 years and 1.57 after 13 years of follow-up, with corresponding rates of prostate cancer mortality of 0.85, 0.78 and 0.79.
Thus, PSA screening was associated with an absolute risk reduction of death from prostate cancer after 13 years of 0.11 per 1000 person–years or 1.28 per 1000 randomly assigned participants, the authors explain. This translates to one fewer prostate cancer death per 781 men invited for screening or one fewer death for every 27 additional prostate cancers detected in the screening programme.
When the researchers accounted for men who did not complete screening, the rate ratio of prostate cancer mortality after 13 years was 0.73 among those who did complete screening, they add.
In an accompanying comment in The Lancet, Ian Thompson, from the University of Texas Health Science Center at San Antonio, USA, and Catherine Tangen, from Fred Hutchinson Cancer Research Center in Seattle, Washington, USA, caution that adjusting for non-compliance is “not a precise science”.
They also note that many prostate cancer deaths recorded in the ERSPC may have been prevalent tumours diagnosed at a late stage on patient enrolment to the study.
Despite this, the commentators describe the findings as “crucially important” for the understanding of prostate cancer screening and treatment.
And they add: “Because the median follow-up from diagnosis of prostate cancer was 6.4 years for the intervention group and 4.3 years in the control group, and because high-risk disease often requires 12–15 years to cause death, we would not be surprised if the benefit of screening becomes more apparent with longer follow-up.”
Schröder F, Hugosson J, Roobol M, et al. Screening and prostate cancer mortality: results of the European Randomised Study of Screening for Prostate Cancer (ERSPC) at 13 years of follow-up. Lancet 2014; Early online publication 7 August. doi:10.1016/S0140-6736(14)60525-0
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