Impact on survival of primary tumor resection in patients with metastatic breast cancer: preliminary results of a retrospective analisys

Background: Treatment of de novo metastatic breast cancer is usually centered around systemic therapy, with local therapy (surgery and radiation therapy) largely reserved for palliation in patients with significant symptoms from primary tumour. The efficacy of locoregional treatment like surgery and/or radiotherapy is still controversial and the debate about surgical resection of primary tumor (PT) in de novo metastatic breast cancer (MBC) patients persists. Methods: All patients with de novo MBC undergone surgical treatment between January 2015 and January 2020 at the Multidisciplinary Breast Center of the Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome were included in this study. The primary endpoint was overall survival (OS) after PT resection, the secondary endpoint was progression free survival (PFS). The survival analyses were done using Kaplan-Meier method. Patients and tumour characteristics were analyzed in an exploratory modality in order to identify prognostic factor. Results: 45 patients received resection of the primary breast cancer (26 mastectomy and 19 breast conserving surgery). Median age of diagnosis was 53 years old (range 25-75 years old). Median follow-up was 25.67 months. The median OS was not reached with 75% of patients alive over 2 years from PT resection. The median PFS was not reached with 64% of patients alive over 2 years from PT resection. For both PFS and OS only the triple negative (TN) immunophenotype appears to be a prognostically unfavorable factor in multivariate analysis. Conclusions: In view of the low number of disease progression events and deaths, although our results are preliminary, surgical treatment of primary breast cancer in metastatic setting seems to be an option after systemic therapies in luminal and HER2 positive breast cancer. Randomized prospective trials in for each immunophenotype are necessary order to confirm this evidence.