Study Shows Radiation Therapy Unnecessary for Women With Cancer of Milk Glands

Many women with the form of breast cancer known as ductal carcinoma in situ (DCIS), a cancer of the milk glands, are unnecessarily receiving expensive and debilitating radiation therapy, according to Dr. Melvin J. Silverstein of the USC/Norris Comprehensive Cancer Center. Until 1980, DCIS was rare, but it now accounts for as much as 40% of breast cancer cases. Normal treatment is surgical removal of the tumor followed by radiation.

Silverstein and his colleagues studied 469 women with DCIS. They report in today’s New England Journal of Medicine that the likelihood of relapse depends on the amount of tissue removed around the tumor. If at least 10 millimeters (about half an inch) of tissue is removed around the edge of the tumor, they found, the cancer is extremely unlikely to recur, and radiation is unnecessary. The cancer shows up on mammograms, but is not visible to the naked eye, so surgeons have to use great care to make sure all of the tumor is removed.

Compiled by Times medical writer Thomas H. Maugh II