I asked one of our medical editor/story reviewers, Richard M. Hoffman, MD, MPH, to write about the news stories predicting what the US Preventive Services Task Force will recommend on prostate cancer screening.
Hoffman is a general internist, is a Professor of Medicine at the University of New Mexico School of Medicine and a staff physician at the Albuquerque VA Medical Center. He also serves as Interim Director for Cancer Prevention at the University of New Mexico Cancer Center. His areas of research interest are prostate and colorectal cancer screening and prostate cancer treatment outcomes, with expertise in clinical epidemiology, health services research, and meta-analysis. He is a medical editor for prostate cancer topics for the Foundation for Informed Medical Decision Making and works with the Foundation to develop shared decision making tools for prostate cancer screening and treatment of localized prostate cancer. The Foundation is also the sole financial supporter of this website.
Once again, the United States Preventive Services Task Force seems headed for a storm of controversy. The New York Times reported today that the Task Force will issue draft recommendations next week advising against prostate cancer screening. The Task Force concluded that screening should be discouraged because it has no net benefit or the harms outweigh the benefits.
Not even two years ago, the Task Force’s recommendation against routinely performing mammography in average-risk women before age 50 outraged professional organizations, advocacy groups, celebrities, politicians, and many other vocal critics. Unfortunately, the somewhat awkward message was distorted to imply that these women should never undergo mammography. In fact, the Task Force was highlighting that mammography for these women involved important trade-offs between potential benefits and harms–and that women needed to make informed, personalized decisions. This is an appropriate message.
However, the new recommendation on prostate cancer seems troubling. In 2008, the Task Force gave prostate cancer screening an “I” rating because the available evidence was considered insufficient to recommend for or against screening–largely because there were no valid data from randomized controlled trials of screening. The Task Force suggested that men be informed about the risks and benefits of screening, though strongly advised against screening men age 75 and older.
In 2009, long-awaited results from the major randomized controlled trials were published. The European Randomized Study of Screening for Prostate Cancer (ERSPC) found that screening reduced prostate cancer mortality by 20%. In contrast, the American Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) found no benefit with screening. However, evaluating PSA in America was challenging because screening was so pervasive that investigators had difficulty enrolling men who had never been screened–or preventing screening in the control group. The validity of the negative PLCO results is uncertain. The ERSPC study was more credible, but showed only a small absolute survival benefit. This benefit must be balanced against the harms of overdiagnosis–finding cancers that would never cause clinical problems during a man’s lifetime–and the resulting overtreatment, which can lead to urinary, bowel, and sexual dysfunction.
Unfortunately, we cannot confidently identify the “overdiagnosed” cancers found with screening, so most men will undergo surgery or radiation therapy. A new strategy of active surveillance might mitigate the harms of overdiagnosis. With this option, men are closely monitored with PSA tests, digital rectal examinations, and biopsies–and will be offered surgery or radiation only if the cancer shows signs of being aggressive.
Ideally, men should be making an informed decision that best reflects their values for the potential downstream consequences of screening. This is indeed the conclusion (based on similar clinical data) that the Task Force reached regarding mammography for women before age 50. The Task Force classified this as a grade “C” recommendation–which is what I expected for prostate cancer screening.
Publisher’s note: Anyone who is not familiar with the USPSTF’s grading system should read about it. The difference between a C and D recommendation is significant.
Another very thoughtful commentary has been posted by Dr. Len Lichtenfeld of the American Cancer Society. Excerpt:
“We have invested over 20 years of belief that PSA testing works. Catch it early, treat it early, and get it out. Save a life. That’s the mantra many of us-including me, as a practicing physician-believed. And here we are all of these years later, and we don’t know for sure. That is not an acceptable situation. Plain and simple, we have not done our homework to prove our point. And the chickens are coming home to roost.
Unfortunately, those “chickens” are men like me who dutifully get our blood tested every year. We have been poked and probed, we have been operated on by doctors and robots, we have been radiated with fancy machines, we have spent literally billions of dollars. And what do we have? A mess of false hope?”
A decision aid on prostate cancer screening, produced by the Foundation for Informed Medical Decision Making, is now available online for a limited time. One interesting aspect is that it features two doctors – one who chooses to be screened using the PSA blood test, and one who declines.