Grading the New US Preventive Services Task Force Prostate Cancer Screening Recommendation

Abstract

ON OCTOBER 11, 2011, THE US PREVENTIVE SERvices Task Force (USPSTF) issued for public comment a draft recommendation statement regarding screening for prostate cancer. The public comment period is a new step taken by the USPSTF prior to finalizing its recommendation statements to help make its recommendations clearer and more useful to primary care providers. In taking this step, the task force signaled its intention to change its 2008 recommendation from a grade I statement (the current evidence is insufficient to assess the balance of the benefits and harms of the service) to a grade D recommendation—“The US Preventive Services Task Force . . . recommends against prostatespecific antigen (PSA)-based screening for prostate cancer.” Following an updated review of the evidence, the USPSTF concluded that there is moderate certainty that the harms of PSA-based screening for prostate cancer outweigh the benefits. The reaction from the media to the impending change has been swift, and organizations that support screening for prostate cancer in general have criticized the new recommendation. Is this reaction justified? In support of its D recommendation, the USPSTF highlighted 3 randomized screening trials (gauged to be of “fair” quality, the highest quality evidence they found). Yet, 2 of these 3 trials demonstrated a benefit to screening in terms of reducing prostate cancer-specific mortality. One trial, the European Randomized Study of Screening for Prostate Cancer, found that 1410 men must be screened an average of 1.7 times over 9 years to prevent 1 prostate cancer death, comparable with the benefit from screening mammography in 50to 59-year-old women (which has a B recommendation from the USPSTF). Although this study prespecified the 55to 69-year-old age group as the core group for analysis of PSA screening, the task force chose to include in its analysis results from several of the countries that enrolled men outside the core age range, negating the positive findings. The other positive study cited by the USPSTF, the Goteborg trial, found a much lower number needed to screen, ie, 293 men would need to undergo screening to save 1 life from prostate cancer. The task force noted that this trial constituted a subgroup of the European Randomized Study of Screening for Prostate Cancer and discounted the results because they were inconsistent with the main results. The third study, the prostate component of the US Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, was indeed negative but was limited by a high prescreening rate in both the screening and control groups of the study and by a similarly high contamination rate in the control group (ie, many men in the control group also underwent screening outside of the trial), mitigating against finding any true benefit to screening. Regardless of the controversy surrounding the question of benefit, there is unanimity in the estimation of harm. All agree that men face serious risks from diagnostic testing and treatment of screen-detected prostate cancers, ranging from sexual, urinary, and bowel injury to treatment-related death. Moreover, many men who are diagnosed with and treated for prostate cancer have cancers that were never destined to harm them, illustrating the thorny problems of overdiagnosis and overtreatment. The crux of the prostate controversy, however, is that many men place such a high value on averting death from cancer that they are willing to undergo risk and harm to achieve that goal. Many other men are not. How can clinicians reconcile this difference in the context of a guideline? It is by engaging men in informed decision making, and in this area, the task force recommendation is consistent with those of other organizations, such as the American Cancer Society. In wording almost identical to that of the American Cancer Society 2010 guideline, the task force recommends that men who are being considered for screening participate in an informed decision, preferably with their physician, that they not be tested without their consent and that communitybased screening without informed consent be discontin-