Benefits and risks from maintenance therapy after first-line chemotherapy in patients with metastatic breast cancer.

1088Background: Current guidelines lack definitive evidence regarding the clinical outcomes associated with different maintenance strategies for metastatic breast cancer (MBC). We aimed to investigate the benefits and risks of different maintenance therapy after first-line treatment of MBC. Methods: We searched for randomized clinical trials (RCTs) investigating maintenance chemotherapy, endocrine therapy or immunotherapy after first-line chemotherapy in MBC. The primary endpoint was progression-free survival (PFS); overall survival (OS) and adverse events (AEs) were secondary endpoints. Direct and indirect evidence for data were combined using random-effects meta-analysis. The GRADE system was used to assess the quality of evidence. The PROSPERO registry number is CRD42017071858. Results: A total of 3,290 patients from 16 RCTs were included. Maintenance chemotherapy resulted into a significantly prolonged PFS (hazard ratio [HR] 0.63, 95% confidence interval 0.54 to 0.73, P = 0.000; high certainty) and OS...