Prognostic Factors for Distant Metastasis in Patients with Locoregional Recurrence after Mastectomy

PURPOSE: The purpose of this study was to identify patients with high risk of distant metastasis (DM) after salvage treatment for postmastectomy locoregional recurrence (LRR). METHODS: We retrospectively reviewed 142 patients who received salvage radiotherapy with or without wide excision for isolated LRR after mastectomy between January 1999 and December 2012. Distant metastasis-free survival (DMFS) was estimated from the date of diagnosis of isolated LRR to the date of DM or last follow-up using the Kaplan-Meier method, and Cox regression analysis was performed to identify prognostic factors for DM. RESULTS: The median follow-up period was 54 months. The major failure pattern was DM (56%) and the 5-year DMFS was 43%. In multivariate analysis, initial N (iN) stage, recurrent N (rN) stage, and hormone receptor (HR) status were significant prognostic factors for DM (5-year DMFS: iN0 vs. iN1-3, 73% vs. 25%, p<0.001; rN0 vs. rN1-3, 61% vs. 29%, p<0.001; HR+ vs. HR-, 49% vs. 21%, p<0.001). CONCLUSION: Patients with lymph node involvement and/or HR- specimens seem to experience more DM than patients with chest wall-only recurrence and HR+ specimens. Further studies are needed to investigate the role of chemotherapy in these patients.