Effectiveness of radiation therapy for older women with early breast cancer

May 17 2006

Elderly women with early-stage breast cancer had a lower risk of recurrence when they were treated with radiation therapy, according to a study in the Journal of the National Cancer Institute.

A clinical trial in 2004 by the Cancer and Leukemia Group B (trial C9343) investigated whether radiation therapy is an effective way to decrease risk of breast cancer recurrence in women 70 years and older with estrogen receptor (ER) positive, early-stage breast cancer. Based on the results of the study, new clinical guidelines suggested that radiation therapy may not be necessary for these women, because of the small benefit, high cost, and side effects of radiation therapy.

In this issue of the journal, Benjamin D. Smith, M.D., of Yale School of Medicine in New Haven, CT, and colleagues identified 8,724 women over age 70 years who underwent surgery for ER-positive, early-stage breast cancer. They examined whether patients who received radiation therapy had a lower risk of recurrence and subsequent mastectomy, and they also tried to identify patients who were most likely to benefit from radiation therapy.

The authors found that radiation therapy was associated with a reduced risk of breast cancer recurrence and the number of subsequent mastectomies. Patients aged 70-79 years who were in good health gained the greatest benefit from radiation therapy. Patients aged 80 years or older with moderate or high levels of other illness gained less benefit from radiation therapy.

The authors conclude, "Our results indicate that important, readily identifiable characteristics can determine which patients are most likely to benefit from radiation therapy."

In an accompanying editorial, Bruce E. Hillner, M.D., from Virginia Commonwealth University in Richmond, Va., and Jeanne Mandelblatt, M.D., from Georgetown University Medical Center in Washington, D.C., compliment Smith and colleagues on a well-designed study with "critical" findings. They write, "High-quality observational studies such as that by Smith et al. can be used to provide information for clinical and policy decision-making for the rapidly growing older population of women at risk for breast cancer. These data could also be used to provide information for shared decision-making between older women and their providers."