September 3, 2004

Radiation after lumpectomy may be unnecessary for some older women

Older women treated with the drug tamoxifen after lumpectomy to remove early-stage breast cancer may safely be able to avoid radiation therapy and its unpleasant side effects. An MGH-led study in the Sept. 2 issue of The New England Journal of Medicine reports that adding radiation to post-surgical tamoxifen treatment of women age 70 or older has minimal impact on the risk of local tumor recurrence and does not improve survival.

"If a patient does not need to have radiation therapy, her quality of life can improve significantly," says Kevin Hughes, MD, of the MGH Cancer Center, who led the study.

Most older breast cancer patients have tumors that can be treated with tamoxifen, which blocks the interaction between estrogen and its receptor protein. Radiation therapy reduces the recurrence of tumors, but breast cancer is less likely to recur in older women. Therefore the researchers investigated whether such patients might do well if they receive tamoxifen alone after surgery.

The five-year study followed 600 women, age 70 or older, with the type of breast cancer treated with tamoxifen. After their tumors were removed by lumpectomy, half the participants received the drug alone and the others received tamoxifen and radiation. Both groups had very low rates of recurrence, with a slightly higher risk in the tamoxifen-only group, but there were no significant differences in terms of distant metastasis, the need for eventual mastectomy or in overall survival. In addition, those receiving radiation had significantly more side effects.

"Each woman and her physician should choose a treatment plan by weighing the slightly increased local recurrence risk against the virtually certain costs of radiation — the patient's time, adverse effects and financial costs," says Hughes.

Barbara Smith, MD, PhD, program director for breast cancer at the Gillette Center for Women's Cancers at the MGH, is a co-author of the study.