Mammography Screening: Clearing Up Some of the Confusion

2 new journal commentaries weigh in on the new guidelines in terms of lives saved by screening.


For the past 10 days, I've been struggling to make sense of the new mammography guidelines recommending a delay in the onset of routine screening from age 40 to age 50. I've wondered whether I should skip the mammogram when I turn 40 next year and have been poring over the scientific data with my colleague Bernadine Healy. (Here's why she's against the new guidelines issued by the U.S. Preventive Services Task Force.)

Women have certainly gotten the message that these guidelines are controversial and haven't been embraced by a majority of health professionals. As I previously blogged, heavyweights like the American Cancer Society and American College of Obstetricians and Gynecologists have stated that women in their 40s should continue to have regular mammograms. And women seem to agree. A USA Today/Gallup poll yesterday showed that 84 percent of women ages 35 through 49 said they planned to have a mammogram before age 50 despite the new guidelines. But the respondents also overestimated the risk of breast cancer for women in their 40s, with 40 percent saying that a 40-year-old's chance of developing breast cancer in the next 10 years was between 20 to 50 percent; the actual risk is just 1.4 percent.

There's no doubt that the controversy has confused and even angered some women. How come our public-health officials can't agree? (Even Health and Human Services Secretary Kathleen Sebelius refused to endorse the government-appointed task force's recommendations.) More important, are 40-something women wasting their time—or even putting their health at risk—by getting screened?

Two commentaries published in today's New England Journal of Medicine may help clear up some confusion. The bottom line is that mammograms reduce a woman's risk of dying from breast cancer even if she's in her 40s. A reduction in deaths is the gold standard by which cancer screening tests are measured. "Screening mammography for women in their 40s is clearly effective," writes Robert Truog, a public-health physician at Harvard Medical School in one of the commentaries. "The problem is that the benefit is tiny and expensive." The cost of screening women in their 40s, he says, comes out to about $680,000 per year of life gained. That's nearly $14 million to buy one 40-year-old woman 20 years of life.

The key, Truog explains, is that "these figures represent population averages." For the individual 40-something woman whose life is indeed saved by having screening mammography, the calculation is meaningless. But these women are few and far between, which is why the British, for example, have determined that the costs of finding them are just too exorbitant. I don't think Americans are so ready to put a cost on a human life, which is why we speak with such loathing about "rationed care."

I also think it pays to look at those issues that the experts do agree upon, the subject of the second commentary appearing in the NEJ. Authors Ann Partridge and Eric Winer from the Dana Farber Cancer Institute list the following five things:

1. The debate over whether to screen women in their 40s isn't new; it's been controversial for many years.

2. The task force isn't prohibiting mammography for women in their 40s, nor deeming it without value, but telling women to make an individual decision with their healthcare provider—pointing out that benefits of screening are limited in younger women.

3. The recommendations should be viewed as a step toward personalized screening with women looking at their individual risk factors—something that will become easier as more is known about genetic predispositions.

4. Experts shouldn't send the message that screening and early detection are of no value. They are, even if this isn't the case for all cancers that are detected. More important, too few women still get regular screening, as my colleague Katherine Hobson points out.

5. No woman in her 40s should be denied insurance coverage for mammograms. This should occur only if there's a broad consensus that screening doesn't save lives. (That's certainly not the case now.)

Given all I've been reading, I have to say that I'm leaning more in favor of having a mammogram when I turn 40. Weighing the risk of experiencing unnecessary biopsies, anxiety, and false negatives (which could give me a false sense of reassurance) against the far smaller possibility that my life could be saved by screening, I'd go with screening any day.