RT FOR BREAT CANCER PATIENTS OVER 70

Lumpectomy Plus Tamoxifen With or Without Irradiation in Women Age 70 Years or Older With Early Breast Cancer: Long-term Follow-up of CALGB 9343

Hughes KS, Schnaper LA, Bellon JR, et al

J Clin Oncol. 2013;31:2382-2387

Study Summary

The purpose of the CALGB 9343 study was to determine whether there is a benefit to adjuvant radiation therapy after breast-conserving therapy for a population of older women with small ER-positive breast cancers who will be treated with adjuvant endocrine therapy for 5 years.

Women over the age of 70 years with early ER-positive invasive breast cancer (tumor measuring no more than 2 cm) and clinically negative axillae were enrolled between 1994 and 1999. A total of 636 participants with stage I breast cancer who were all treated with lumpectomy (axillary exploration was left to the discretion of the treating surgeon) were randomly assigned to receive tamoxifen plus radiation therapy or tamoxifen alone. Primary endpoints were time to local or regional recurrence, frequency of mastectomy, breast cancer-specific survival, time to distant metastasis, and overall survival.

After a median follow-up of 12.6 years, investigators found no significant differences in time to mastectomy, time to distant recurrence, breast cancer-specific survival, or overall survival. At 10 years, 98% of patients who received dual-modality therapy were free from locoregional recurrence as compared with 90% in the group treated with tamoxifen alone. In the group that received tamoxifen alone, 42 of 319 women relapsed, compared with 23 of 317 in the group that received tamoxifen plus radiation therapy. More women in the tamoxifen group had local and regional relapses and were treated with surgery or radiation at the time of relapse. There was no significant difference in the number of distant relapses between the 2 treatment groups.

After long-term follow-up, there remains a benefit in terms of reduction of local recurrence for patients receiving tamoxifen plus radiation therapy. This does not translate into a survival advantage, however, and does not affect the rate of distant metastases. These findings allow physicians and patients a legitimate option to minimize treatment at the time of breast cancer diagnosis.