Mammograms Less Accurate in Obese Women
Obese, Overweight Women Face More False Positive Mammograms
May 24, 2004 -- Obese and overweight women are at increased risk of getting suspicious results from screening mammograms, research shows.
Mammograms don't miss any more cancers in heavy women than in thin women. But the more a woman weighs, the greater the risk that her mammogram will have false positive results. That means more tests - and more anxiety.
Joann G. Elmore, MD, MPH, of the University of Washington in Seattle, and colleagues analyzed more than 100,000 mammograms from nearly 70,000 women. The report their findings in the May 24 issue of Archives of Internal Medicine.
"Compared with underweight or normal weight women, overweight and obese women were more likely to be recalled for additional tests," Elmore and co-workers write. "Obese women had more than a 20% increased risk of having a false positive mammogram result."
At the personal level, it's not a huge increase in risk. Overall, a woman faces about one in 10 chance of getting a false positive result on a screening mammogram. Obesity increases that risk from 10% to 12%.
But those extra tests add up fast. For an estimated 10 million obese women in the U.S., this means some 200,000 false positives. At $600 per retest, that adds up to an extra $120 million in U.S. health-care costs. And that doesn't even begin to measure the personal costs.
"We cannot put a quantitative value on the resultant anxiety these 200,000 women would additionally experience," Elmore and colleagues note.
Even so, obese women need mammograms more than skinny women. That's because a breast examination is more likely to miss small tumors in women with very large breasts.
The researchers suggest that larger mammography plates may help get better images of women with large breasts. They also suggest that weight loss may lower the likelihood of an unnecessarily traumatic experience when it's time for a routine mammogram.