Mammograms Can Boost Breast Cancer Risk, So Why Are Women Encouraged to Get Them?
Experts discuss a popular, but imperfect method
The health of women worldwide stands in troubled territory as they continue to receive conflicting reports about what methods can detect, prevent and cure potentially fatal diseases.
Just as the U.S. Preventive Services Task Force declared ovarian cancer screenings ineffective—for frequently resulting in false-positives and thus unnecessary operations with high complication rates—the Netherlands Cancer Institute has cited the radiation from mammograms as a potential cause of breast cancer. Ultimately, the method used to detect the disease could very well be increasing its chance of development.
The Netherlands Cancer Institute specified that the increase applies to young women with an existing "high familial risk," reporting that "any diagnostic use of radiation before age 30 [can increase the] breast cancer risk by 90 percent for carriers of BRCA1 or BRCA2 mutations." These mutations impair the body's ability to fix double-strand breaks in DNA; the breaks are caused by ionizing radiation.
But Dr. Diana Buist, an epidemiologist whose work focuses primarily on early detection of breast cancer, assures that the two factors are not exclusive of one another.
"It's really important that women understand that family history of breast cancer is not the same thing as being a BRCA 1 or BRCA 2 carrier," Buist said. "Most women with a family history do not carry either of these mutations."
In fact, only about 15 percent of women who get breast cancer have a family member diagnosed with it. Eighty-five percent of breast cancers, however, occur due to the genetic mutations that happen as a result of the aging process.
For carriers of BRCA, the American Cancer Society (and the Netherlands Cancer Institute) recommend an annual MRI (or magnetic resonance imaging) screening, a less-risky, non-ionizing radiation technique. The same is encouraged for women who were treated for Hodgkin disease.
Yet, every October, it's not an MRI that pink ribbon-wearing, awareness-raising activists promote. Instead, it's mammograms—despite the method's tendency to result in false alarms (or suspicious results that later prove to be benign), leading some women to undergo unnecessary treatments for tumors that aren't actually life-threatening.
"It's a complex issue," said Dr. George Autz, Director of Breast MRI Services at New York's Complete Women's Imaging. "I think the breast MRI clearly is a better performing examination in BRCA mutation patients, there's no question; for them, the cancer detection rate by MRI is literally tenfold compared to mammography. But it's hard to give up the mammogram because that's considered the golden standard, it's the one that's been studied the most, and it's the only one that's ever been showed to have mortality reduction associated with it. Plus, I find that the mammogram will occasionally find breast cancer that even the MRI doesn't see, usually it's a non-invasive type. The mammogram, while it's not perfect, it's clearly the best that we have."
"Best," according to a report by the Journal of the American Medical Association last December, refers to only a 13 percent probability that a woman with screen-detected breast cancer will avoid a breast cancer death because of a mammogram.
MRIs, unfortunately, are "much more expensive" in comparison, according to the U.S. Preventative Services Task Force, and are not recommended for women at average risk for breast cancer, but instead for those with an atypical lifetime risk greater than 20 percent.
Dr. David Mankoff, a Professor of Radiology at the University of Pennsylvania, and Chief of Nuclear Medicine & Clinical Molecular Imaging, admits that mammography has its flaws, but insists decisions be made by women—and their doctors—on a case-by-case basis.
"It is important to remember that although typically exceedingly small, radiation exposure from ionizing medical imaging carries some risk of cancer induction," he said. "The choice to use imaging is always a consideration of benefit versus risk. I would not counsel young women to avoid mammography on the basis of this report, but rather to discuss risk versus benefit with their doctors."