Prognostic factors affecting the outcome of salvage radiotherapy for isolated locoregional recurrence after mastectomy

Objectives: To evaluate the prognostic factors affecting the outcome of salvage radiotherapy for isolated locoregional recurrence after mastectomy. Methods: Between May 1988 and April 2002, 65 breast cancer patients underwent radiotherapy as a component of salvage treatment for isolated locoregional recurrence after mastectomy. The sites of failure were as follows: chest wall in 37 patients, regional lymph nodes (LNs) in 23 patients, and combined chest wall and LNs in 5 patients. None of the patients had previously been treated with radiation. Thirty-nine patients had surgical resection, and 55 patients received systemic chemotherapy and/or hormonal therapy for recurrent disease. In 51 cases (78.5%), the chest wall and ipsilateral regional lymphatics including supraclavicular, axillary, and internal mammary LNs were irradiated. Median dose was 50.4 Gy (range: 50-71.5). Median duration of follow-up was 52 months (range: 2-206). Results: The 5-year overall survival rate was 48.1%. On multivariate analysis, patients without initial nodal involvement had better overall survival (P = 0.0118). The 5-year locoregional progression-free survival rate was 69.8%, and time to recurrence (>36 months vs. ≤36 months) had an influence on the outcome with borderline significance (P = 0.0775). The 5-year distant metastasis-free survival rate was 42.1%. Lack of systemic therapy after recurrence (P = 0.0089) and age <50 years at recurrence (P = 0.0145) were significant prognostic factors predicting poor distant metastasis-free survival. Conclusions: Radiotherapy for isolated locoregional relapse after mastectomy achieved locoregional control in about two-thirds of patients. Major pattern of failure was distant relapse, and systemic therapy is warranted to prevent secondary dissemination.