Medical Hum-drum Hijacked by Politics and Emotion
By Leo Kretzner, December 7, 2009.
What does the average person want from medical studies?? A heaping order of certainty with some simple advice on the side, hold the nuance.
Yet what do we usually get?? Relative odds and statistics covered with a creamy sauce of complexity. No wonder people get upset when medical thinking changes.
With the hugely partisan political debate over health care reform currently underway in the US, it was inevitable that the medical question of when to screen for breast cancer quickly became overtly politicized after the US Preventive Services Task Force (USPSTF) released its new recommendations for women receiving mammograms, on November 19, 2009. (http://www.ahrq.gov/clinic/uspstf/uspsbrca.htm#summary)
There have been hundreds unto thousands of comments on public news blogs, and Republican lawmakers in congress, decreeing that the recent modifications to cancer screening mammography guidelines are a clear sign of “Obamacare” and the start of health care rationing.
The reality is that these recommendations and updates are being made on a regular basis, all the time – and the current panel members were in fact Bush-appointed. There have been dozens of such recommendations every year from the USPSTF and other agencies on everything from abdominal aortic aneurism to visual acuity and youth violence. (http://www.ahrq.gov/clinic/uspstf/uspstopics.html)
Not only that, but doubts about the effectiveness of mammography in women under the age of fifty have actually been around for at least a decade. The very same USPSTF group behind last month’s controversial guideline updates acknowledged these doubts in its previous report in 2002, but at that time the data were not strong enough to actually advise against testing women in their forties.
The new recommendations, for all their controversy, actually say this is a topic that women and their doctors need to discuss and settle on an individual basis.
As the vice-chair of the USPSTF, Dr. Diana Petitti, said at that time: "So, what does this mean if you are a woman in your 40s? You should talk to your doctor and make an informed decision about whether mammography is right for you based on your family history, general health, and personal values." (http://www.ahrq.gov/clinic/uspstf/uspsbrca.htm)
What they advise against is the automatic screening of women in their forties with mammography, while advising for doctor-patient discussion on this – isn’t that something we usually like to see more of?
A similar controversy played out a few months ago with regard to men being screened for prostate cancer with the blood test for PSA, prostate specific antigen, and follow-up biopsy. Curiously, there was very little of the emotionally charged political rhetoric surrounding the male screening question, as though men and their prostates were somehow less politically salient.
Politics notwithstanding, the issues surrounding screening are the same for breast and prostate cancer. (They apply to all cancer in theory, but we don’t have relatively simple screening options for most of them.)
The issue of most concern to doctors is whether the actual numbers of people who die from their cancer – the mortality rate – is lower for those who get screened. Although this may seem intuitively obvious – and it was the expectation of many researchers – the results of several studies are decidedly not lending their support to the pro-screening/early-detection lobbies, for either breast or prostate. Mortalities have been modestly reduced, at best.
However, from the public’s point of view, we’d like to know what our own, individual risks are. The average person isn’t interested in overall mortality, just their own or next of kin. So responses on blogs to the new mammography guidelines were often along the lines of ‘This is bunk! My sister was only 37 when she discovered a lump…’
It seems everyone suddenly knows someone whose life has without a doubt been spared by mammography or a PSA test. The reality is that we can’t be really certain of this.
“The evidence now shows… that many small collections of cancer cells may be perfectly well contained by our body’s natural defenses, and often even disappear on their own. Cancer, we now know, is not a one-way street. In some cases, small tumors may appear, grow a bit, and then stop, or even go away,” according to doctors David Sevan-Schreiber, Lorenzo Cohen, and Donald Abrams, writing in the Houston Chronicle on December 6, 2009. (http://www.chron.com/disp/story.mpl/editorial/outlook/6755592.html)
As the ability of doctors to detect early cancers improves, we and they are confronting the question of whether some small cancers are being treated that would have never gone on to become real problems.
This wouldn’t matter if treatments had no side-effects, but of course they do – mastectomies and chemotherapy or radiation for women and possible impotence or incontinence for men following prostatectomies or radiation treatment. Screening itself is not without small risks of increased radiation on breasts and possible infection with prostate biopsies.
For men with low-grade prostate cancer, doctors sometimes offer the option of ‘watchful waiting’ (also called ‘active surveillance’) – tracking PSA levels and periodically rebiopsying to see if a small tumor is progressing into something more aggressive.
This is rarely done for women with a small breast tumor “because there is the option of minimally invasive surgery for small breast cancers (ie, lumpectomy), compared to the more invasive surgery for prostate removal,” explains Dr. Steven Katz, a breast cancer expert at the University of Michigan.
Given the level of fear people have about cancer, it’s likely that women in their forties being offered the option of whether or not to get a mammogram – and men being offered the option of watchful waiting – will often decide to err on the side of caution and get the test and/or treatment.
The survival instinct is part of human nature, no matter what the overall mortality statistics say.
Leo Kretzner is a PhD molecular biologist and science writer in Claremont, CA.