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

On October 11, 2011, the US Preventive Services Task Force (USPSTF) issued for public comment a draft recommendation statement regarding screening for prostate cancer.¹ 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 prostate-specific 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,² 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 50- to 59-year-old women (which has a B recommendation from the USPSTF). Although this study prespecified the 55- to 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,³ 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.⁴

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 community-based screening without informed consent be discontinued. The American Cancer Society guideline states that “men should have an opportunity to make an informed decision with their health care provider about whether to be screened for prostate cancer, after receiving information about the uncertainties, risks, and potential benefits associated with prostate cancer screening.”⁵ One point from which the task force recommendation departs from the American Cancer Society guideline is in the USPSTF's failure to address the use of patient decision aids. This is unfortunate, given the considerable evidence supporting their use in promoting effective health care decision making, including decisions about prostate cancer screening.⁶

In light of these issues, did the USPSTF get it right? The only other cancer screenings to receive a D recommendation from the USPSTF are for ovarian, pancreatic, and testicular cancer, none of which has any randomized trial evidence favoring screening in contrast to the conflicting evidence surrounding prostate cancer screening. It appears that the prostate screening evidence review conducted for the task force warrants a C recommendation, which would indicate that it “recommends against routinely providing the service. There may be considerations that support providing the service in an individual patient. There is at least moderate certainty that the net benefit is small.”¹ This would also be consistent with the recommendations of virtually all other major organizations, including the American Cancer Society and the American Urologic Association,^{5 ,7} which recommend against routine testing but promote actively engaging men in the screening decision, and is supported by comments from others about the task force's proposed change.⁸

The significance of upgrading from a D to a C recommendation is more than just incremental. A D recommendation indicates that physicians have no obligation to mention the issue of prostate cancer screening in their care of patients because the D grade indicates that testing asymptomatic men should not occur. Consequently, many men will have no opportunity to consider the issues surrounding prostate cancer screening. A C recommendation also recommends against routine screening, that is, screening without involving men in the decision. The fundamental difference, however, is that a C recommendation does allow for individualized decision making, such that men can be apprised of the potential benefits and harms of screening and decide in partnership with their physician whether to proceed.

The USPSTF deserves credit for sharpening the focus on the risks and harms of prostate cancer screening. But by recommending against prostate cancer screening altogether, the task force discounts the evidence supporting the effectiveness of screening and disregards the great value that many men place on averting a cancer death. Given the discrepant screening recommendations that now exist, practicing physicians have a choice: they can either abandon prostate cancer screening altogether or redouble their efforts to communicate the salient issues to age-appropriate healthy men, allowing them to incorporate their own values into a screening decision they can live with.