Women with dense breasts have a greater likelihood of cancer
While science searches for answers, women should quiz radiologists about their own breast density now. "I'm of the school that the more you know, the more your power is," says Mary Daly, head of the Margaret Dyson Family Risk Assessment program at Fox Chase Cancer Center in Philadelphia. There's no need to panic. While their risk is higher, most women with dense breasts won't get cancer: Boyd says a 50-year-old woman with density in more than half her breast still has only about a 5 percent chance of getting breast cancer in the next decade, compared with about 2.5 percent for the average 50-year-old woman. But a few precautions may be in order. Talking to a doctor about the potential danger of using combined hormone therapy may be wise, for example. The jury's still out on other interventions.
And there's good reason to be extra diligent about being screened, possibly by one of the newer technologies (box). A study published in 2005 showed that digital mammograms are more effective than traditional ones using X-ray film at detecting cancer in women with dense breasts. Studies of ultrasound's power have also been promising; researchers funded by the National Cancer Institute and the Avon Foundation will issue a preliminary report this autumn on whether there's evidence that ultrasound screening in these women can reliably pick up tumors not detected by a mammogram. If so, the American Cancer Society will review whether its screening recommendations should add ultrasound to mammography for women with dense breasts, says Robert Smith, the organization's director of screening.
In the meantime, a woman with dense breasts can ask her doctor whether it's worthwhile to seek out either technology. That may be tricky and costly-digital mammography is available in only about 15 percent of imaging facilities, for example, and insurance might not cover the full cost. About 35 percent of facilities can do ultrasound.
In any case, a mammogram is the first line of defense, says Wendie Berg, a radiologist and breast imaging consultant in Lutherville, Md., and head of the ultrasound trial. "If it's convenient, it's probably a good idea to have it done digitally, but it's less important than to have a regular one at a good facility," she says. Regular clinical breast exams are a must, too.
Pam Schmid, whose tumor didn't show up on a mammogram, is a big proponent of the low-tech self-examination. She felt a lump during her regular check, agreed to a wait-and-see period of six months, then insisted on an ultrasound. One tumor showed up, and a subsequent MRI revealed four. Schmid urges women to ask their radiologists to explain mammogram results, find out the density percentage of their breasts, consider further imaging, and trust their intuition.
At this point, there are clearly more questions than answers about density and cancer. But because of the number of women affected, the implications of finding answers are huge, says density researcher Jack Cuzick, head of the department of epidemiology, mathematics, and statistics at the Wolfson Institute of Preventive Medicine in London. Assuming that it is possible to lower risk by lowering density, he says, getting women with 50 percent density down to 15 percent "could eliminate a third of breast cancer."