Age is an important factor when considering tamoxifen therapy for older women with early-stage breast cancer, according to a large retrospective study presented at the 52nd Annual Meeting of the American Society for Radiation Oncology. The findings indicate that older women treated with conservative surgery and radiation therapy (CS + RT) derive only limited benefit from tamoxifen.
Researchers from the Cancer Institute of New Jersey and Yale University reported that women age 65 years and older treated with CS + RT, who did not receive adjuvant tamoxifen did not appear to have worse outcomes. Use of tamoxifen in this cohort of women did not confer any systemic benefit, in terms of contralateral breast cancer rates, systemic failure rates, and survival rates, they found.
Currently, adjuvant tamoxifen is recommended for all women with estrogen receptor (ER)–positive breast carcinoma regardless of age. It has been unclear, however, whether CS + RT was as effective as CS + RT plus tamoxifen in older women with small, node-negative breast cancer.
The researchers reviewed a single-institution database of 2478 patients and selected 224 patients who were 65 years or older and who had pathologic T1N0M0 breast cancer treated with CS + RT between 1979 and 2003. The median follow-up time was 62.6 months. Of the 224 women, 102 (45.5%) received tamoxifen and 122 (54.5%) did not.
There were four local relapses and 15 distant metastases during the study. The 10-year local relapse-free survival (LRFS) was 98% in both the tamoxifen group and the no tamoxifen group. The 10-year distant metastasis-free survival (DMFS) was 83% in the tamoxifen group, and 89% in the no tamoxifen group. Ten-year cause-specific survival and overall survival (OS) were also statistically similar in the two groups.
“We found that tamoxifen did not offer a benefit at almost every end point we looked at, including local control, distant control of the disease, breast cancer–specific survival as well as overall survival,” said study investigator Rahul Parikh, MD, a resident in radiation oncology at the Robert Wood Johnson Medical School, New Brunswick, New Jersey. “These findings held up in multivariate analyses, and this is an expensive drug and it is not without side effects.” He said that older women “may not need it and they may do well enough with adjuvant radiation therapy.”