Radiation Following Mastectomy in Node-Negative Breast Cancer Beneficial in Subset of Patients

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According to results recently presented at the 45th annual meeting of the American Society for Therapeutic Radiation and Oncology, radiation to the chest following a mastectomy improves outcomes in patients with node-negative breast cancer whose cancer is 3 cm or greater and/or whose cancer is within 2 mm of the surgical margin.

Breast cancer claims the lives of approximately 40,000 women annually in the United States alone. Early-stage breast cancer refers to cancer that has not spread from its site of origin. Patients with early-stage breast cancer have a high cure rate with currently standard treatment options, particularly those with no cancer spread to the axillary (under the arm) lymph nodes, referred to as node-negative. Standard treatment for patients with node-negative breast cancer typically includes the removal of the cancer, referred to as breast conserving therapy, followed by radiation therapy and/or chemotherapy. Historically, patients were treated with a mastectomy (removal of the entire breast) and were not routinely offered radiation therapy. Some patients today who are diagnosed with early breast cancer still opt for a mastectomy. Researchers are evaluating different patient and disease characteristics to determine which patients may benefit from radiation therapy, which kills remaining cancer cells to the area it is administered, while sparing patients who do not benefit from radiation therapy from the side effects of the treatment.

Recently, researchers from the Massachusetts General Hospital compiled data involving 281 women with node-negative breast cancer who were treated at their institution. These women were treated with a mastectomy alone, and had an average follow-up of at least 12 years. Overall, recurrence rates on the side of the chest of the original cancer (locoregional) occurred in 8.4% of patients. At 12 years following diagnosis, patients with cancer greater than 3 centimeters had a 23% rate of locoregional recurrence. Patients who had cancer cells within 2 millimeters of the outside margins of the removed breast had nearly a 40% rate of locoregional recurrence.

The authors concluded that women with node-negative breast cancer who decide to undergo a mastectomy may benefit from follow-up radiation therapy if their cancer is greater than 3 cm and/or their cancer is within 2 mm of surgical margins, as patients with these characteristics have a high recurrence rate in the area that radiation therapy would be administered. Patients with node-negative breast cancer who choose to undergo a mastectomy may wish to speak with their physician about the risks and benefits of follow-up radiation therapy in their individual case.

Reference: Jagsi R, Abi Raad R, Goldberg S, Michaelson J, Taghian A. Loco-regional recurrence rates and prognostic factors for failure in node-negative patients treated with mastectomy alone: implications for postmastectomy radiation. Proceedings from the 45th annual meeting of the American Society for Therapeutic Radiation and Oncology. October, 2003. Abstract # 9. S128.