Locoregional treatment outcomes for inoperable anthracycline-resistant breast cancer

Purpose: To assess the therapeutic outcomes and treatment-related morbidity of patients treated with radiation for inoperable breast cancer resistant to anthracycline-containing primary chemotherapy. Methods and Materials: We analyzed the medical records of breast cancer patients treated on five consecutive institutional trials who had been designated as having inoperable locoregional disease after completion of primary chemotherapy, without evidence of distant metastases at diagnosis. The cohort for this analysis was 38 (4.4%) of 867 patients enrolled in these trials. Kaplan-Meier statistics were used for survival analysis, and prognostic factors were compared using log-rank tests. The median follow-up of surviving patients was 6.1 years. Results: Thirty-two (84%) of the 38 patients were able to undergo mastectomy after radiotherapy. For the whole group, the overall survival rate at 5 years was 46%, with a distant disease-free survival rate of 32%. The 5-year survival rate for patients who were inoperable because of primary disease extent was 64% compared with 30% for those who were inoperable because of nodal disease extent (p = 0.0266). The 5-year rate of locoregional control was 73% for the surgically treated patients and 64% for the overall group. Of the 32 who underwent mastectomy, the 5-year rate of significant postoperative complications was 53%, with 4 (13%) requiring subsequent hospitalization and additional surgical revision. Preoperative radiation doses of ≥54 Gy were significantly associated with the development of complications requiring surgical treatment (70% vs. 9% for doses <54 Gy, p = 0.0257). Conclusion: Despite the poorer prognosis of patients with inoperable disease after primary chemotherapy, almost one-half remained alive at 5 years and one-third were free of distant disease after multidisciplinary locoregional management. These patients have high rates of locoregional recurrence after preoperative radiotherapy and mastectomy, and the morbidity associated with this approach may limit dose-escalation strategies. Alternative therapeutic strategies such as novel systemic agents, use of planned myocutaneous repair for closure, or radiation combined with radiosensitizing agents, should be considered in this class of patients.