At a median follow-up of 10.9 years, an EORTC study has shown that irradiation of regional nodes in patients with stage I, II, or III breast cancer has a marginal effect on overall survival, the primary endpoint (at 10 years, overall survival was 82.3 % for regional irradiation versus 80.7% for no regional irradiation, (HR=0.87 (95%CI: 0.76, 1.00), p=0.06). The results also showed that disease-free survival, distant-disease-free survival, and breast cancer mortality were significantly improved. Side effects were very limited, although very long-term toxicity of radiation remains unknown.
The phase III EORTC 22922-10925 trial was conducted to evaluate what effect regional node irradiation, i.e., irradiation of the internal mammary and medial supraclavicular lymph nodes, would add to whole breast or chest wall irradiation following surgery in patients with stage I, II, and III breast cancer.
Prof Philip Poortmans of the Radboud university medical center, Nijmegen, The Netherlands says: