SAN DIEGO—Omitting adjuvant tamoxifen may not put women aged older than 65 years with early-stage breast cancer at increased risk for local or distant disease recurrence, according to a large, retrospective study presented at the 52nd annual meeting of the American Society for Radiation Oncology.
Researchers from the Cancer Institute of New Jersey and Yale University reported that women aged 65 years and older treated with conservative surgery and radiation therapy (CS + RT), who did not receive adjuvant tamoxifen, did not appear to have worse outcomes. Use of tamoxifen in this cohort did not confer any systemic benefit, in terms of contralateral breast cancer rates, systemic failure rates, and survival rates, according to the investigators.
Currently, adjuvant tamoxifen is recommended for all women with estrogen receptor–positive breast carcinoma re gardless of age. It has been unclear, however, whether CS + RT is as effective as CS + RT plus tamoxifen in older women with small, nodenegative breast cancer.
The researchers reviewed a singleinstitution database of 2478 patients and selected 224 patients aged 65 or older who had pathologic T1 N0 M0 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.
The researchers found that there were four local relapses and 15 distant metastases during the study. The 10 year local relapse-free survival was 98% in both the tamoxifen group and the no tamoxifen group. The 10-year distant metastasis-free survival was 83% in the tamoxifen group, and 89% in the no tamoxifen group. Ten-year cause-specific and overall survival 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, resident in radiation oncology at 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.”
Parikh said if these findings are confirmed in other studies, it may be time to rethink how breast cancer patients 65 and older are managed. “The side effects of tamoxifen can include hot flashes, endometrial hyper plasia, which can in a small number of women lead to endometrial cancer,” he said. “So perhaps, if these women don’t benefit from this drug, they may not need it and they may do well enough with adjuvant radiation therapy.”