Long term survival study of de-novo metastatic breast cancers with or without primary tumour resection

Abstract

Background: Treatment of de novo metastatic breast cancer is usually palliative with systemic treatment; surgical excision of the primary tumour is reserved in patients with significant symptoms from the primary tumour. Survival benefit of primary tumour surgery remains controversial. Methods: This study was registered in the research registry (researchregistry.com). All patients treated with de novo metasatatic invasive ductal breast cancer (MBC) between January 2007 - December 2016 were retrieved from a prospectively-maintained database. Patient baseline demographic and tumour characteristics were compared. Overall survival (OS) was analysed using Kaplan Meier Method and log-rank test. Multivariate analysis was performed to evaluate the survival prognosticators. Result: Median age of diagnosis was 53 year-old (Range 24–91 years old). 91 patients received resection of the primary tumour, including 86 mastectomies and 5 breast conserving surgeries (surgical group). 81 patients were never treated surgically (non-surgical group). Baseline patient and tumour characteristics were comparable (apart from being younger age in the surgical group). 5-year OS in surgical group was significantly better than non-surgical group (43.9% vs. 33.9%, p=0.026). Multivariate analysis found that advanced age (Hazard ratio: 1.034, p=0.005, 95% CI 1.010–1.058) and presence of visceral metastasis (Hazard ratio: 1.672, p=0.038, 95% CI 1.028–2.719) remained statistically significant through multivariate analysis with stepwise Cox regression; while positive oestrogen receptor (ER) status was the only positive prognosticator in the analysis (Hazard ratio: 0.42, p=0.001, 95% CI 0.256–0.688). Conclusions: Surgical excision of primary breast tumour may confer survival benefit in de novo MBC, in carefully selected patients.