It's the added pounds, not impaired detection, that's to blame, study concludes
TUESDAY, Nov. 25 (HealthDay News) -- Being overweight boosts the risk of getting advanced breast cancer for older women, according to a new study that looked at more than 287,000 women and took into account their mammogram habits.
The weight itself is to blame for the added risk, the researchers concluded.
"Women who are above their healthy weight have higher levels of circulating estrogens," noted study lead author Dr. Karla Kerlikowske, director of the Women Veterans' Comprehensive Health Center at the San Francisco Veterans Affairs Medical Center. "The estrogen is promoting tumor growth," she said.
In previous studies, Kerlikowske and her colleagues looked at postmenopausal women who took hormone replacement therapy (HRT) and found an increased breast cancer risk. In the current study, expected to be published in the Dec. 3 issue of the Journal of the National Cancer Institute, they looked at postmenopausal women not using HRT.
In years past, some research has suggested that the increased risk for breast cancer for obese women may be due to their not getting screened adequately, or because their tumors are perhaps more difficult to detect on mammography.
But those risk factors were ruled out in the current study. "We took into account how often they were screened and how well you could detect [the cancer]," Kerlikowske said. "There was still an increased risk."
In her study, Kerlikowske and her colleagues collected ongoing data from mammograms performed on more than 287,000 women past menopause. The women got routine mammograms. The researchers did not find that the tumors were harder to detect in women who were overweight or obese.
Nevertheless, "the risk of an advanced stage cancer for an obese women is 56 percent to 82 percent higher than for a normal-weight woman," Kerlikowske said
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