Elderly women with estrogen receptor (ER)-positive early breast cancer may be able to safely forgo radiation therapy after lumpectomy, according to data from a large Intergroup trial presented at the 2010 ASCO Annual Meeting. The only significant benefit for the addition of radiation therapy to tamoxifen was a small reduction in local recurrence-an absolute 7% decline compared to tamoxifen alone.

"At 10 years' follow-up, 95% of the patients in each group had no distant metastases, which is essentially a 95% cure rate," said Kevin S. Hughes, MD, a member of the Department of Surgical Oncology at Massachusetts General Hospital, Boston.

The findings add further evidence that women aged 70 and older with early-stage breast cancer can undergo lumpectomy plus tamoxifen therapy alone without compromising their survival. Dr. Hughes made it clear, however, that the results cannot be applied to younger women, for whom radiation therapy is the standard of care.

Dr. Hughes presented the results on behalf of the Cancer and Leukemia Group B (CALGB), the Radiation Therapy Oncology Group (RTOG), and the Eastern Cooperative Oncology Group (ECOG).

Recurrence Rate Differed

CALGB 9343 included 636 women age 70 and older with stage I (tumor size ≤ 2 cm), ER-positive (or ER-indeterminate), node-negative breast cancer who had a lumpectomy with negative margins. They were randomly assigned to receive tamoxifen (n = 319) or tamoxifen plus radiation (n = 317), and then followed for a median time of 12 years. The current analysis was of outcomes at 10 years.

No significant differences were observed between the groups with respect to breast preservation rates, breast cancer-specific survival, or overall survival (Fig. 1), Dr. Hughes reported. In-breast recurrence, however, was inferior when radiation therapy was eliminated. Local recurrences were observed in 6/317 (2%) in the tamoxifen-radiotherapy arm and 27/319 (9%) in the tamoxifen-only arm (P = .0001).

Dr. Hughes remarked that this was a small benefit. "We would have to irradiate 319 women to prevent 21(7%) in-breast recurrences," he noted.

Overall survival tended to be low because these were older women who died of other causes. ASCO President George Sledge, MD, of Indiana University School of Medicine, commented at a press briefing, "We have many elderly patients who have a hard time getting back and forth to radiotherapy appointments for 6 to 7 weeks. This study gives those patients real comfort that they are not missing out on a lifesaving treatment," he said. "But there are going to be patients who look at the data and think that a 6% to 7% reduction in in-breast recurrence is important to them because they want to avoid the need for retreatment. This study says that there are options for physicians and patients, and that is its value." ■

Reference

1. Hughes KS, Schnaper LA, Cirrincione C, et al: Lumpectomy plus tamoxifen with or without irradiation in women age 70 or older with early breast cancer. 2010 ASCO Annual Meeting. Abstract 507. Presented June 7, 2010.