Radiation after lumpectomy may be unnecessary for many older women

Tamoxifen alone may adequately control breast cancer, avoiding side effects

Older women treated with tamoxifen after removal of early-stage breast cancer by lumpectomy may safely be able to avoid radiation therapy and its unpleasant side effects. In the Sept. 2 New England Journal of Medicine, investigators from several major cancer research groups report that adding radiation to post-surgical tamoxifen treatment of women age 70 or older does not improve survival, has minimal impact on the risk of local tumor recurrence and does not prevent the need for eventual mastectomy. “If a patient does not need to have radiation therapy, her quality of life can improve significantly,” says Kevin Hughes, MD, of the Massachusetts General Hospital (MGH) Cancer Center, who led the study. “By showing that radiation therapy has very little impact on outcome for these patients, we can help each woman and her physician decide on the right treatment.”

Many breast cancers depend on the hormone estrogen to grow. So tamoxifen, which blocks the interaction between estrogen and its receptor protein, is used to treatment tumors that have that protein on the surface of their cells. Most older breast cancer patients have receptor-positive tumors and receive tamoxifen, a medication that has few side effects.

Radiation has been a standard post-surgical treatment for women having lumpectomies, but the therapy can be both inconvenient and unpleasant, with side effects such as pain, swelling, and skin discoloration. Several studies have shown that, although radiation reduces tumor recurrence, it does not improve overall survival. Because breast cancer is less likely to recur in older women, the research team investigated whether such patients might do well if they receive tamoxifen alone after surgery.

Over a five-year period, more than 600 patients at almost 30 centers across the U.S. enrolled in the study. All the participants were age 70 or older, with early-stage (2 cm or less), receptor-positive tumors that had been removed in lumpectomy procedures. They were randomly assigned to receive either tamoxifen alone or tamoxifen plus radiation as postsurgical treatment.

At the end of the study period, the only significant difference between the groups was in the risk that the tumor would recur at or near its original site. Both groups had very low rates of recurrence; but while those in the tamoxifen-only group had a 4 percent risk, those who also received radiation had an only 1 percent risk. There were no significant differences in terms of distant metastasis, the need for mastectomy after recurrence or overall survival. Both groups had exactly the same number of breast cancer deaths – three in each group, a rate that reflects the less aggressive nature of breast cancer in this age group. As expected, those receiving radiation reported more pain, swelling, stiffness and other side effects than did the tamoxifen-only participants.

“The local recurrence risk in both groups was extremely low, and women who have not had radiation have the option of another lumpectomy if they do have recurrence in the same breast. Once a patient has had radiation, however, she must have a mastectomy if her tumor recurs,” says Hughes, an assistant professor of Surgery at Harvard Medical School. “In the long run, 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.”