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 > or =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 > or =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.