Primary tumor resection in stage IV breast cancer: A systematic review and meta-analysis

The impact of primary tumor resection (PTR) on survival is still controversial in stage IV breast cancer. This systematic review and meta-analysis aimed to evaluate the impact of PTR on overall survival (OS) in stage IV breast cancer.

Comprehensive literature search was conducted to identify studies comparing PTR with no PTR for stage IV breast cancer. The quality of the studies was assessed using Cochrane risk of bias tool and Newcastle-Ottawa Scale. We used subgroup and meta-regression analysis to assess the contribution of demographic and clinical factors to heterogeneity.

Data on 714 patients in 3 randomized controlled trials (RCTs) and 67,272 patients in 30 observational studies were included. One RCT was terminated early due to poor recruitment, and the remaining two RCTs' design were different, thus RCTs were only performed systematic review without meta-analysis. The pooled outcomes of 30 observational studies showed PTR significantly improved OS (HR = 0.65; 95%CI, 0.61 to 0.70, P < 0.001, I² = 80%). Additionally, PTR was associated with better distant progression-free survival (HR = 0.42; 95%CI, 0.29 to 0.60) but did not impact progression-free survival. Subgroup analysis showed PTR benefit in patients who had only one metastatic site (HR = 0.62, 95%CI. 0.48 to 0.81), bone-only metastasis (HR = 0.61, 95%CI. 0.37 to 1.00), with negative margin (HR = 0.61, 95%CI. 0.58 to 0.65).

PTR should not be part of routine clinical practice in stage IV breast cancer but might be performed in selected patients. Our findings highlight PTR might be valuable in patients with limited disease burden or attaining clear margin.