Original Article: Prostate Cancer Screening; Prostate Cancer Screening: The Pendulum Has Swung, and the Burden of Proof Is with Proponents [Editorial]
Issue Date: October 15, 2015
to the editor: An important fact that is never stated in articles that recommend against routine screening for the potentially fatal disease of prostate cancer, including the one recently published in American Family Physician,1 is that if the U.S. Preventive Services Task Force and the American Academy of Family Physicians current recommendations for prostate cancer screening are followed, then more men will die of the disease.
Prostate cancer screening has become less common since 2012, and it is estimated that more than 1,200 more men will eventually die from prostate cancer because they have not been screened.2,3 Maybe that number is not high enough for researchers to be concerned, but it concerns me and my patients. I have no doubt that once deaths from prostate cancer begin to rise because of a lack of screening, then these recommendations will change. In the meantime, individual physicians will need to decide what to do. I know that I will advise my male patients older than 50 years to ignore these recommendations and to receive prostate-specific antigen (PSA) screening. The more appropriate question is not whether to screen for prostate cancer, but whether to treat it if it is found. That is where the focus of this debate should be.
in reply: The goal of our article was to review current evidence regarding the value of PSA to screen for prostate cancer.1 Although many modeling studies have tried to predict the future effect of PSA screening, these studies are based on many assumptions, and we did not include them in our review. The European Randomised Study of Screening for Prostate Cancer (ERSPC), with 13 years of follow-up, showed that mortality from prostate cancer was about 0.4% of the total mortality in both the screening and control groups with no difference in overall mortality.2 This meant that 99.6% of the men who died during the 13 years of follow-up died for reasons other than prostate cancer, with no difference in the total number of men who died in each group. The only U.S. screening randomized controlled trial3 and a Cochrane review of all prostate cancer screening trials did not show a reduction in prostate cancer–specific mortality or overall mortality with screening.4 The best evidence we have consistently shows that PSA screening does not reduce overall mortality. Perhaps the discussion should move on to how we can focus our effort on other topics in medicine that we know will decrease overall mortality.
Although one study estimates that without screening more than 1,200 more men will die from prostate cancer in 13 years,5 this estimate is based on many assumptions, including that the cancers detected from screening are identical to the cancers detected in the ERSPC, and that the underlying risk of prostate cancer is similar between the ERSPC population and the general U.S. population.6 The ERSPC results show that we need to screen 800 men to save one life after 13 years, with 27 extra prostate cancer diagnoses. This presents a real dilemma for a practicing physician: If you believe that you have saved the life of one patient by diagnosing prostate cancer through PSA screening, then the next 27 patients you diagnose with prostate cancer using PSA screening will only be harmed.
in reply: Dr. Stevens argues that others and I have failed to consider that current recommendations to scale back routine PSA screening will increase national prostate cancer mortality by 1,200 deaths per year. This invented statistic is precisely what I dispute. The 1,200 number comes from the fact that since PSA screening guidelines changed, fewer men have had the test, and around 33,000 fewer cancers have been detected. Remember, all these men are spared the anxiety, treatments, and complications of a prostate cancer diagnosis.1 Then, it assumes that the number needed to detect—number of diagnoses needed to avert one prostate cancer death—is 27, as it was in one out of five randomized trials of the PSA screening.2 But, in my editorial, I explained why looking at this one trial in isolation is misleading. A Cochrane review looking at all the trials shows no reduction in prostate cancer mortality.2
Based on the Cochrane review, it is expected that a reduction in PSA screening will avert many complications and harms with no increase in deaths due to prostate cancer. The refusal of many physicians to stop screening will result in many men continuing to suffer harms of screening with no countervailing benefits to justify it.3
Also, this discussion omits a growing concern that looking solely at prostate cancer deaths does not take into account many of the harms of PSA screening. A diagnosis of prostate cancer can lead to increases in cardiovascular death and suicide,4 and treatment for prostate cancer can lead to increases in second malignancies.5 For these reasons, it is possible that reductions in prostate cancer death seen in some trials are offset by deaths from other causes. Elsewhere, I have argued that, at a minimum, patients undergoing PSA screening should be told explicitly that it has not been shown to improve overall mortality, and therefore cannot be said to “save lives.” 6
PSA screening has clearly resulted in much harm to many men. Whether it has also resulted in any benefits is the point of dispute. For a widespread public health intervention, that simply is not good enough.