Adding radiation therapy to chemotherapy improves survival in patients with high-risk breast cancer

For patients with high-risk breast cancer treated with radical mastectomy and adjuvant chemotherapy, the addition of radiation therapy leads to better survival outcomes with few long-term toxic effects, according to a 20-year follow-up of a randomized trial, which appears in the January 19 issue of the Journal of the National Cancer Institute.

The British Columbia randomized radiation therapy trial was designed to determine the effect on survival of the addition of locoregional radiation therapy (radiation to the lymph nodes and chest wall) to a course of chemotherapy after radical mastectomy in premenopausal women with lymph node–positive breast cancer. Between 1979 and 1986, 318 patients were randomly assigned to receive no radiation therapy or to receive radiation. A 15-year follow-up found that radiation therapy was associated with improved breast cancer survival but not with overall survival.

In this 20-year follow-up of the British Columbia trial, Joseph Ragaz, M.D., of McGill University Health Center in Montreal, and colleagues found that the chemotherapy and radiation regimen, compared with chemotherapy alone, was associated with improvement in all end points analyzed. This included a 32% reduction in breast cancer mortality and a 27% reduction in overall mortality compared with chemotherapy alone. In addition, long-term toxic effects, including cardiac deaths, were acceptable for both groups of patients.

"Our results, and those from other groups, confirm that in situations where residual disease remains, adjuvant chemotherapy alone in high-risk breast cancer patients is suboptimal and that the addition of locoregional radiation therapy is important to achieve the highest cure rate," the authors write.

In an editorial, Timothy Whelan, B.M., B.Ch., and Mark Levine, M.D., of the Juravinski Cancer Centre in Hamilton, Ontario, discuss the use of locoregional radiation therapy in breast cancer patients and note that fewer clinicians accept its use in moderate-risk patients. "Because uncertainties continue about the effectiveness of locoregional radiation therapy after mastectomy in moderate-risk patients, we strongly urge that a randomized controlled trial be mounted to resolve these uncertainties," they write.