Tamoxifen treatment after removal of early-stage breast cancer by lumpectomy may enable women to avoid radiation therapy and its unpleasant side effects. Reported in the New England Journal of Medicine, investigators said 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 study-leader Kevin Hughes of the Massachusetts General Hospital (MGH) Cancer Center. "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 estrogen to grow. Tamoxifen, which blocks the interaction between estrogen and its receptor protein, is used to treat tumors that have that protein on the surface of their cells. Most older breast cancer patients have receptor-positive tumors.
Radiation has been a standard post-surgical treatment for women having lumpectomies, but the therapy can be both inconvenient and unpleasant. 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 received tamoxifen only.
The five-year study involved women who were 70 or older, with early-stage receptor-positive tumors that had been removed in lumpectomy procedures. They were randomly assigned to receive either tamoxifen alone or tamoxifen plus radiation. At the end of the study, the only significant difference between the groups was in the risk that the tumor would recur 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. 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.
