Supraclavicular failure after breast-conserving therapy in patients with four or more positive axillary lymph nodes when prophylactic supraclavicular irradiation is omitted

Purpose The incidence of supraclavicular metastasis as the initial failure and the failure patterns in patients with four or more positive axillary lymph nodes (PALNs) after breast-conserving therapy (BCT) without prophylactic supraclavicular irradiation were investigated. Materials and methods Between 1991 and 2002, a total of 48 women with four or more PALNs underwent BCT without prophylactic supraclavicular irradiation (33 patients with 4–9 PALNs; 15 patients with ≥10 PALNs). Results The median follow-up time was 50 months. Among the patients with 4–9 PALNs, 3% had isolated supraclavicular metastasis as the initial failure, and 30% had distant metastasis as the initial failure. Among patients with ≥10 PALNs, 7% had isolated supraclavicular metastasis as the initial failure, and 40% had distant metastasis as the initial failure. The 4-year isolated supraclavicular failure rates were 5% for all patients, 3% for patients with 4–9 PALNs, and 8% for patients with ≥10 PALNs. Conclusion In patients who had undergone BCT and had had four or more PALNs, the major failure pattern was distant failure with or without locoregional failure; isolated supraclavicular failure as the initial failure comprised a less common failure pattern. Omission of prophylactic supraclavicular irradiation may be acceptable for this subset of patients.