Locoregional therapy of the primary tumour in de novo stage IV breast cancer in 216 066 patients: A meta-analysis

Patients presenting with de novo stage IV metastatic breast cancer have a complex disease which is normally treated with palliative intent and systemic therapy. However, there is mounting evidence that resection of the primary tumour and/or localised radiotherapy (locoregional therapy; LRT) could be associated with overall survival improvements. We aimed to conduct a meta-analysis to inform decision making. Using the PubMed, Cochrane and Ovid SP databases, a literature review and meta-analysis were conducted to assess the effect of LRT on overall survival. Studies were analysed for the impact of LRT on survival. All forms of LRT resulted in a significant 31.8% reduction in mortality (N=42; HR=0.6823 (95% CI 0.6365; 0.7314)). Surgical resection resulted in a significant 36.2% reduction in mortality (N=37; HR=0.6379 (95% CI 0.5974; 0.6811)). The prospective trials reported a 19.23% reduction in mortality which was not statistically significant (N=3, HR=0.8077 (95% CI 0.5704; 1.1438). 216 066 patients were included. This is the largest meta-analysis regarding this question to date. Our meta-analysis shows that LRT of the primary tumour seems to improve overall survival in de novo stage IV disease. Therefore, this therapeutic option should be considered in selected patients after a careful multidisciplinary discussion.