Purpose: To assess the impact of comprehensive locoregional therapy and systemic therapy on disease control and survival for postmastectomy patients with isolated locoregional recurrence (ILRR). Methods and Materials: A total of 115 postmastectomy breast cancer patients treated for ILRR were included. Of the patients, 98 underwent comprehensive locoregional treatment (local tumor excision plus postoperative radiotherapy), and 17 received definitive radiotherapy alone. Involved- field radiotherapy was given to 69 patients, whereas entire-field radiotherapy (both involved-field and elective-field, involving the chest wall and regional lymphatics) was given to 46 patients. Systemic therapy consisting of hormone therapy, chemotherapy, or both was given to 69% of patients. Results: Patients treated with comprehensive locoregional treatment had a significantly better 5-year invasive disease-free survival ( IDFS) and overall survival (OS) after ILRR than patients treated with definitive radiotherapy alone (IDFS rate, 51% vs. 16%, p = 0.006; OS rate, 62% vs. 37%, p = 0.017). Patients with the most comprehensive locoregional treatment( recurrent tumor excision and entire-field radiotherapy) and systemic therapy had a significantly better 5-year IDFS and OS than patients given either treatment or neither treatment(IDFS rate , 52% vs. 39%,p = 0.011; OS rate, 63% vs. 50%,p = 0.026). Multivariate analysis revealed that positive axillary lymph nodes, Grade III tumor, negative estrogen and progesterone receptor status at primary diagnosis, disease- free interval of less than 2 years, and less comprehensive locoregional treatment were significantly associated with worse IDFS and OS. Conclusions: Use of comprehensive locoregional therapy and systemic therapy can achieve good survival outcome in a substantial proportion of postmastectomy patients with ILRR. ; 附設醫院腫瘤醫學部 ; 醫學院附設醫院 ; 期刊論文