Breast Wars: It’s Not Just Mammograms
Why skipping self-exams may be even more controversial.
In the furor over last week’s recommendation by the U.S. Preventive Services Task Force that women not begin having regular mammograms until they are 50, and then have them every two years from age 50 to 74 rather than annually (with exceptions for women at high-risk for the disease), another of the task force's findings has gotten lost in the scuffle. In addition to finding that the benefits of earlier mammograms, and of more frequent mammograms, are unwarranted because of "at least moderate certainty that the net benefit is small," the panel was even more critical of teaching women breast self-exam.
It was also more certain.
On the mammogram recommendations, the panel recommended that doctors "offer or provide this service only if other considerations support it." On breast self-exams, it was even more negative, recommending that physicians actively "discourage [my emphasis] the use of this service." Question: for the conspiracy mongers who say that the task force's mammogram conclusions are a nefarious plot by the Obama administration (which did not even appoint the panel; the Bush administration did) to cut health-care costs by rationing a life-saving test, what are we to make of the breast self-exam (BSE) recommendation? Last time I checked, a woman who decides not to do one every month isn't saving her insurer, the government, or anyone else a dime. Yet the panel still nixed the idea that BSE should be done regularly. (It opted instead for "breast awareness": definitely pay attention if you experience nipple discharge, find a large lump, or notice any other significant change.
Unbeknownst to most women, this isn't some off-the-wall view, as I blogged last year. The Mayo Clinic notes that "breast exams, once thought essential for early breast cancer detection, are now considered optional … [T]here's no evidence that breast exams can" save lives. The National Breast Cancer Coalition (one of my favorite advocacy groups because it hews so closely to the science, (letting the politically correct chips fall where they may) calls the idea that breast self-exams save lives "Myth #1." It's worth quoting the group's explanation:
"The evidence actually shows that breast self-exam (BSE) does not save lives or detect breast cancer at an earlier stage. For decades, women age 20 and older have studied shower cards, read pamphlets, watched videos and prodded silicon breast models to find a hidden lump—each resource teaching BSE as a life-saving personal responsibility. Seems to make sense. In reality, there is no scientific evidence to prove this is true…Many organizations share NBCC's viewpoint on BSE. The National Cancer Institute (NCI) no longer prints a BSE guide."
Several studies have cast doubt on the value of BSE. A 2003 study in Russia found that breast self-exam "did not affect mortality" from breast cancer. A 2002 study in China, conducted by scientists at the Fred Hutchinson Cancer Research Center in Seattle and published in the Journal of the National Cancer Institute (JNCI), reached the same conclusion.
One problem is that breast self-exam is very hard to do accurately. Clinical breast exam—that is, the kind done by a doctor—has a sensitivity of 40 percent to 69 percent, which means it finds that percentage of lumps (the range reflects what different studies have found, as this analysis from 2002 finds. Self-exams are, not surprisingly, even worse, finding between 12 percent and 41 percent of lumps. In an editorial accompanying the JNCI paper, Russell Harris and Linda Kinsinger of the University of North Carolina, Chapel Hill, wrote, "At least for the great majority of women whose [exam] practice is not optimal, it does not reduce the risk of dying of breast cancer."
Why in blazes not? "By the time a woman feels a lump, the cancer may have been growing for eight to 10 years," cancer surgeon Susan Love told me at the time.
Maybe we can move beyond the paranoia and hysteria to ask why neither mammograms nor breast self-exams save many lives. (How many lives are saved by mammograms? The task force estimates that 1,904 women in their 40s would have to be screened for a decade in order to save a single life. The numbers aren't much better for women in their 50s: to save one life, you have to screen 1,300 for a decade. I'm not aware of a similar calculation for BSE, but the numbers are undoubtedly equally abysmal.) A good part of the reason why screening asymptomatic patients (which is what screening is: looking for cancer in people with no symptoms of the disease) is not more effective, I am sorry to say, is that even breast cancers caught super-early might not be treatable. That is, they have already dispatched malignant cells into the lymph system, through which they travel to the bones and brain and kill you, as I explained in a column earlier this year.
The flip side of aggressive cancers is indolent ones. These are so slow-growing that failing to find them, by mammogram or self-exam, won't hurt you. An estimated 85 percent of breast cancers fall into the super-aggressive or indolent category—that is, whether they kill you or leave you alone is barely affected by whether they're discovered "early" by mammogram, breast self-exam, or anything else.
That leaves a paltry 15 percent where early detection and treatment might matter. More bad news: not only can neither mammogram nor BSE tell which category a tumor falls in, but neither can microscopic examination of the tumor cells. Bottom line: the fact that so few breast tumors fall into the category of being more treatable if caught early is a big reason why the numbers—screen 1,904 women for a decade to save a single life—stink.
What's needed is not more posturing and hang-wringing, but doing something about the real travesty of breast-cancer treatment. It's not that experts are trying to deny women a life-saving test in order to save money; surely the task force's verdict on breast self-exam shows that this is about science, not money. No, the tragedy of breast cancer is the lack of an effective treatment for too many of these tumors. In 2009, an estimated 40,170 women will die of breast cancer. Susan Love again: "To believe [that BSE saves lives] is wishful thinking," she said. "It feeds all our prejudices about empowering women to take their health into their own hands…[But] pretending things work gets in the way of finding things that are better." It is long past time to focus energy, scientific talent, and money on "finding things"—not only treatments, but biomarkers revealing the presence of breast cancer long before those malignant cells have formed a lump—that are better.