Breast Removal: The Latest in Cancer Prevention

Healthfacts, Feb, 1999

The news made headlines across the country. Cutting off both healthy breasts will reduce a high-risk womans chances of dying of breast cancer by 90%. Prophylactic mastectomy, as this operation is called, has long been practiced by surgeons, but this is the first time a well-designed study has identified a clear benefit. That such a drastic measure would be hailed as prevention is troubling. It focuses unintended attention on the fact that, despite billions of dollars poured into breast cancer research, little is known about how to prevent this disease.

Mayo Clinic physicians followed 639 women who underwent prophylactic mastectomies between 1960 and 1993. All were high-risk because they had a very strong family history of breast cancer. About 20 breast cancer deaths would be expected in this population, but only two occurred (The New England Journal of Medicine, 1/14/99). Breast cancer can develop after prophylactic mastectomy because it is difficult, if not impossible, for surgeons to remove all breast tissue. Uncertainty over the operations benefit centered on the remaining tissues potential for harboring cancerous cells. After 14 years, seven women in the Mayo Clinic study developed breast cancer. One woman was diagnosed with breast cancer that had spread to the bone 12 years after her prophylactic mastectomy.

Still, the finding offers hope to women who are truly at high risk for breast cancer; for example, women with one or more first-degree relatives who died of breast cancer before the age of 45. The operation, however, has the potential for abuse. Breast cancer awareness activities, largely funded by Zeneca, a breast cancer drug manufacturer, and promoted by the American Cancer Society, have encouraged women to overestimate their odds of developing this disease.

Even if prophylactic mastectomy were confined to the truly high risk, its benefit comes at a stiff price. Of the 639 women in the Mayo Clinic study, 621 suffered the emotional trauma and physical aftereffects of mastectomy; yet all would have survived without the operation. In this regard, prophylactic mastectomy is depressingly similar to the treatments awaiting women who have breast cancer. Whether its chemotherapy or radiotherapy, overtreatment of the majority to save a small minority has been the story of breast cancer treatment for decades.

Prophylactic mastectomy is too drastic for most women. Whats left? Mammography is a suboptimal screening test that will, at best, prolong the lives of only 30% of older women whose breast cancers are found early.

Women who want to reduce their risk of breast cancer with daily doses of tamoxifen have no more than four years worth of research to guide them. The evidence to support yearly breast examinations is even less impressive. We are now 28 years into the war on cancer, and the overwhelming majority of the current spending for breast cancer research still goes to treatment and detection. Isn't it time we knew more about more about prevention?