Prostrate Cancer Screening -- Finding Clarity in the Controversy
Should you get screened for prostate cancer?
Posted Jul 07, 2010
I'm just going to get it out there: since I started my general medicine practice last July I have not screened a single patient for prostate cancer. Not one.
For the men out there who are unaware of the controversy around prostate cancer screening and who get their PSA blood test and rectal exam every year, this will come as an absolute shock. To the initiated, doctors and patients who are familiar with what is probably the greatest controversy in preventive health care, this admission will be interesting but not head turning. They know the data supporting prostate cancer screening is poor but at the same time may be surprised that my patients and I have taken such a definite stance on it.
Overall, deaths rates from prostate cancer have decreased since screening was widely adopted in the early 1990s. However, from clinical trials in which men were randomized to receiving screening or no screening, there have been no consistent differences in deaths rates from prostate cancer - the men who get screened for prostate cancer with PSA blood tests and rectal exams fair no differently than men who aren't screened. What's more is that men who receive screening get a lot more testing, a lot more biopsies, and a lot more treatment including surgery and radiation therapy, but again, without any clear benefit.
Last March the New England Journal of Medicine reported on the early results of two large-scale clinical trials - the U.S. Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial and the European Randomized Study of Screening for Prostate Cancer (ERSPC) - that many hoped would end the prostate cancer controversy. But these results too were mixed. While the PLCO trial showed no reduction in deaths from prostate cancer through screening, the ERSPC showed a small mortality benefit. Both trials had significant flaws though many experts favor the ERSPC trial because fewer men in the non-screened group received screening compared to the PLCO study (less cross-contamination). However, even if you accept the ERSPC data, the numbers in support of prostate cancer screening are sobering: in order to prevent one death from prostate cancer 1410 men would have to be offered screening and an additional 48 would need to be treated.
It turns out that your take on prostate cancer screening depends largely on your approach to evidence-based medicine. In a simplified view, there are the Whys and Why-nots. The Why-nots feel that we have the technology to screen for prostate cancer, that while the evidence is not clear that prostate cancer screening improves outcomes screening makes sense, and that doing something to stop this terrible disease is better than doing nothing. In short, Why-nots need a good reason not to screen for prostate cancer and, in the absence of one, they support it. The Whys simply feel there is no convincing evidence to support prostate cancer screening because it has not been definitively shown to saves lives. Whys need a good reason to screen for prostate cancer and in the absence of one they are against routine screening.
Early in my medical training I became a Why. I'm only going to recommend screening to a patient that comes to see me in clinic when the evidence is clear it's going to help him. Yes, prostate cancer is a horrible disease. Yes, PSA blood tests and rectal exams are the best we got. And yes, some studies have shown that screening improves health and that additional studies may one day once and for all make a definitive case for screening. But until then I'm going to offer prostate cancer screening to my male patients without endorsing it. I'm going to inform them of the controversy, the plusses and the minuses. And then I'm going to make the best use of the 15 minutes I have with my patient and move on to those preventive health measures that are actually proven to make a difference.
The United States Preventive Services Task Force (USPSTF), the gold standard in preventive services, also generally takes the Why approach. When they last evaluated the evidence in August 2008 (before the PLCO and ERSPC results were available), they concluded that the current evidence was insufficient to assess the balance of benefits and harms of screening in men younger than 75 years. In men over age 75, the task force recommended against screening.
Regardless of which side you take, the key is what you say to the patient in front of you. Whether or not a doctor supports prostate cancer screening, it is the patient who ultimately decides for himself what is best. Until the evidence offers any more clarity (the PLCO and ERSPC trials are ongoing), no doctor should be strongly advocating for or against screening and must be wary of the subtext as well as the text of their discussions.
With zero patients in one year electing to undergo screening for prostate cancer, despite "fair and objective" counseling about both sides of the issue, I for one will be taking a closer look at what I say to my patients about prostate cancer.
Copyright Shantanu Nundy, M.D.
To learn more about prostate cancer screening, visit http://www.cancer.gov/cancertopics/pdq/screening/prostate/patient.
To read USPSTF's guidelines, visit http://www.ahrq.gov/CLINIC/uspstf/uspsprca.htm.
The NEJM articles I referenced are N Engl J Med 2009;360:1310-1319 (PLCO study) and N Engl J Med 2009;360:1320-1328 (ERSPC).