Internal Mammary and Medial Supraclavicular Irradiation in Breast Cancer

Original Article
Internal Mammary and Medial Supraclavicular Irradiation in Breast Cancer

Philip M. Poortmans, Ph.D., Sandra Collette, M.Sc., Carine Kirkove, Ph.D., Erik Van Limbergen, Ph.D., Volker Budach, Ph.D., Henk Struikmans, Ph.D., Laurence Collette, Ph.D., Alain Fourquet, Ph.D., Philippe Maingon, M.D., Mariacarla Valli, M.D., Karin De Winter, M.D., Simone Marnitz, M.D., Isabelle Barillot, Ph.D., Luciano Scandolaro, M.D., Ernest Vonk, M.D., Carla Rodenhuis, Ph.D., Hugo Marsiglia, Ph.D., Nicola Weidner, Ph.D., Geertjan van Tienhoven, Ph.D., Christoph Glanzmann, Ph.D., Abraham Kuten, M.D., Rodrigo Arriagada, M.D., Harry Bartelink, Ph.D., and Walter Van den Bogaert, Ph.D. for the EORTC Radiation Oncology and Breast Cancer Groups

N Engl J Med 2015; 373:317-327July 23, 2015DOI: 10.1056/NEJMoa1415369


Background

The effect of internal mammary and medial supraclavicular lymph-node irradiation (regional nodal irradiation) added to whole-breast or thoracic-wall irradiation after surgery on survival among women with early-stage breast cancer is unknown.

Methods

We randomly assigned women who had a centrally or medially located primary tumor, irrespective of axillary involvement, or an externally located tumor with axillary involvement to undergo either whole-breast or thoracic-wall irradiation in addition to regional nodal irradiation (nodal-irradiation group) or whole-breast or thoracic-wall irradiation alone (control group). The primary end point was overall survival. Secondary end points were the rates of disease-free survival, survival free from distant disease, and death from breast cancer.

Results

Between 1996 and 2004, a total of 4004 patients underwent randomization. The majority of patients (76.1%) underwent breast-conserving surgery. After mastectomy, 73.4% of the patients in both groups underwent chest-wall irradiation. Nearly all patients with node-positive disease (99.0%) and 66.3% of patients with node-negative disease received adjuvant systemic treatment. At a median follow-up of 10.9 years, 811 patients had died. At 10 years, overall survival was 82.3% in the nodal-irradiation group and 80.7% in the control group (hazard ratio for death with nodal irradiation, 0.87; 95% confidence interval [CI], 0.76 to 1.00; P=0.06). The rate of disease-free survival was 72.1% in the nodal-irradiation group and 69.1% in the control group (hazard ratio for disease progression or death, 0.89; 95% CI, 0.80 to 1.00; P=0.04), the rate of distant disease-free survival was 78.0% versus 75.0% (hazard ratio, 0.86; 95% CI, 0.76 to 0.98; P=0.02), and breast-cancer mortality was 12.5% versus 14.4% (hazard ratio, 0.82; 95% CI, 0.70 to 0.97; P=0.02). Acute side effects of regional nodal irradiation were modest.

Conclusions

In patients with early-stage breast cancer, irradiation of the regional nodes had a marginal effect on overall survival. Disease-free survival and distant disease-free survival were improved, and breast-cancer mortality was reduced. (Funded by Fonds Cancer; ClinicalTrials.gov number, NCT00002851.)