Locoregional Treatment of the Primary Tumor in Patients with De Novo Stage IV Breast Cancer: A Radiation Oncologist’s Perspective

• Published in: Clinical breast cancer 2018-04, Vol.18 (2), p.e167-e178
• Main Authors: Choi, Seo Hee, Kim, Jun Won, Choi, Jinhyun, Sohn, Joohyuk, Kim, Seung Il, Park, Seho, Park, Hyung Seok, Jeong, Joon, Suh, Chang-Ok, Chang Keum, Ki, Kim, Yong Bae, Lee, Ik Jae
• Format: Article
• Language: English
• Subjects: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Breast - pathology; Breast - surgery; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Breast Neoplasms - therapy; Disease-Free Survival; Female; Hematology, Oncology and Palliative Medicine; Humans; Kaplan-Meier Estimate; Lymphatic Metastasis - pathology; Lymphatic Metastasis - radiotherapy; Mastectomy; Middle Aged; Neoplasm Recurrence, Local - epidemiology; Neoplasm Recurrence, Local - pathology; Neoplasm Recurrence, Local - prevention & control; Neoplasm Staging; Obstetrics and Gynecology; Primary metastatic breast cancer; Prognosis; Radiotherapy; Radiotherapy, Adjuvant - methods; Retrospective Studies; Surgery; Survival Rate; Treatment Outcome
• ISSN: 1526-8209; 1938-0666
• DOI: 10.1016/j.clbc.2017.06.002

Abstract Background The aim of this study was to assess the outcomes of patients with de novo stage IV breast cancer after locoregional treatment (LRT) of primary site. Patients and Methods We studied 245 patients diagnosed with de novo stage IV breast cancer. LRT of the primary tumor (+ systemic therapy) was performed in 82 patients (34%) (surgery: 27, surgery + radiotherapy (RT): 46, and RT: 9). Among those undergoing surgery, 64 (88%) underwent mastectomy, and 9 (12%) underwent breast-conserving surgery (BCS). Local recurrence-free survival (LRFS) and overall survival (OS) were investigated, and propensity score matching was used to balance patient distributions. Results The 5-year LRFS and OS rates were 27% and 50%, respectively. Advanced T stage (T4), liver or brain metastasis, ≥5 metastatic sites, and absence of hormone therapy were significant adverse factors for LRFS, while T4 stage and absence of hormone therapy were significant for OS. The LRT group demonstrated significantly more favorable outcomes (5-year LRFS: 61%, 5-year OS: 71%), especially after surgery. After matching, survival rates remained significantly higher for patients who received LRT (5-year LRFS 62% vs. 20%, p < 0.001, 5-year OS 73% vs. 45%, p = 0.02). BCS + RT was superior to mastectomy ± RT, which can be attributed to more patients with a low tumor burden undergoing BCS + RT. Outcomes were better with post-mastectomy RT in selected patients (≥N2, ≥T3, or T2N1). Conclusions Upfront LRT including RT is an important option together with systemic therapies for de novo stage IV breast cancer.