Increased life expectancy as a result of non-hormonal targeted therapies for HER2 or hormone receptor positive metastatic breast cancer: A systematic review and meta-analysis

Abstract This article aimed to assess the clinical effectiveness of non-hormonal targeted therapies (TTs) in terms of increase of median progression-free survival (PFS) and overall survival (OS) in receptor-positive metastatic breast cancer (MBC) patients by performing a systematic review and meta-analysis. We systematically searched relevant randomized controlled trials and extracted data about number of patients on targeted and comparator therapy, receptor status, line of treatment, median PFS and OS, p values, hazard ratios (HRs) and 95% confidence intervals (CI). Inverse variance was used to estimate pooled HRs, chi-square test for heterogeneity and Jadad scale for quality were applied. Thirty-eight studies ( n  = 17,192 patients) were eligible for inclusion. TTs added 3.3 months to the median PFS [0.7–9.6; HRs 0.74, 95% CI 0.71–0.77] of receptor-positive MBC patients and prolonged their median OS with 3.5 months [0–4.7; HRs 0.90, 95% CI 0.82–0.98]. The highest increase in median PFS of 3.6 months was found in HER2−/hormone receptor(HR)+ patients, while the highest increase in median OS of 7.2 months was observed in HER2+/HRmixed status patients. First-line TTs were most effective in increasing the median PFS in the HR+/HER2− group with 2.0 months, and in the HER2+/HRmixed group by adding 4.7 months to the median OS. Second-line TTs were most effective for HER2−/HR+ patients by adding 2.6 months to their PFS, and for HER2+/HRmixed patients by adding 3.1 months to their median OS. Albeit small, the gain in months of median PFS and median OS was significant. Importantly, the results reported show large variation, and thus routinely applying a personalized approach seems warranted.