The new breast cancer screening guidelines released last week, along with the supporting study, are among the most disputatious medical recommendations in recent memory. Critics on the right charge government rationing, while those on the left suspect an insurance company conspiracy to cut essential coverage. Adding gasoline to the fire is the even more heated health reform debate that has led its combatants to hijack the mammography issue to bolster their own particular views, pro and con.
To get past the politics, I read the study. It is hardly a page turner, but it’s a credible scientific analysis of the available data on breast cancer screening. A key question it addresses is how effective mammography is for women under age 50—an issue that has ping-ponged back and forth across the medical policy community for four decades. In this latest volley, the U.S. Preventive Services Task Force (USPSTF), citing the study, recommends “…against routine screening mammography in women aged 40 to 49 years.” But then it equivocates with, “The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient’s values regarding specific benefits and harms.”
The recommendation is based on the relative benefits of testing women in their 40’s (one averted death per 1000 women) against the harm caused by overdiagnosis (finding and treating cancers that don’t shorten a woman’s life), by excessive radiation, and by false positives (inconvenience, psychological harm, and unnecessary follow-up imaging and biopsies). Here are some of the study’s findings (which may surprise you):
- Without screening, the average 40-year-old woman has a 12-15% lifetime breast cancer risk and a 3% mortality risk.
- The advantage of commencing screening at age 40 (vs. 50) is very small—a 3% reduction in mortality (i.e. reducing the 3% probability of death to 2.9%).
- Starting annual screening at age 40 (vs. 50) increases median life-years by 33 per 1000 women screened, or about 12 days per woman.
- Slow-growing tumors are much more common than fast-growing ones, and the ratio of slow- to fast-growing tumors increases with age, so little survival benefit is lost between screening every year versus every other year.
- For the small subset of women with aggressive, fast-growing tumors, even annual screening is not likely to confer a survival advantage.
These findings are quite interesting, but hardly controversial. The squabble arises from the panel’s using them to craft new, more restrictive recommendations on when women should seek mammography screening. To do that, it had to go beyond the science and apply human judgment as to whether the benefits of early screening outweigh the harm. This was further complicated—greatly, in my view—by the panel’s use of dissimilar measures for benefit and harm: death rates and life-years for the former, and false-positives and overdiagnoses for the latter. Comparing one with another is a lot like comparing avocadoes with chairs. It produces no objective score or benchmark against which the judgment part can then be applied. This practically guaranteed a major fracas when the result was to recommend restricted screening. That’s probably why the task force ended up waffling on its recommendation.
One oft-voiced fear is that these new guidelines will lead to rationing of mammographies by the government. But so far, no one has noticed the elephant in the living room: mammographies cost only $170 each (national average). How can they be denied to anyone when all but the poorest women can afford 25 cents a day for every-other-year screening if she and her doctor think it’s essential?
Wouldn’t it make more sense to simply drop insurance coverage for mammography altogether and let women decide for themselves when to spend their own money for it, based on whatever statistics, guidelines, desires, fears, and doctor recommendations they choose to heed? The purpose of insurance is to pay for things that are expensive and that you normally don’t expect to need. Mammography is neither. True, insurers love to cover it, because they get to add not only the screening cost to women’s premiums, but also nice margins for administration and profit. But why should American women, arguably the world’s most savvy consumers, overpay for that? And if mammographies were a normal consumer purchase, you can bet that enterprising medical entrepreneurs will figure out how to offer them for a lot less than $170, possibly even less than today’s copayments for the procedure.
Speaking of insurance, how do you suppose the current House and Senate health reform bills deal with mammography? Both the pending Senate bill and the recently passed House bill require insurers to cover preventive services that have been given an A or B grade by the USPSTF. Since the task force gave a C to under-age-50 mammography, (you heard it here first) it will not be a required benefit. So you can ignore all that political posturing by the usual suspects claiming that nothing will change. It just has—or will, if the bill becomes law.
But is this rationing? Not really. Almost everybody can already afford it as a normal consumer expense. And giving poor women the money to buy it (or something else) would be a trivial expense for the taxpayer.
What do you think? Please let me know in the comment space below.