The Predictive Role of PIK3CA Mutation Status on PI3K Inhibitors in HR+ Breast Cancer Therapy: A Systematic Review and Meta-Analysis

AIM: To evaluate the impact of PIK3CA mutation status on clinical outcomes of HR+ breast cancer treated with PI3K inhibitors. METHODS: A comprehensive literature search was conducted in online databases from inception to December 31, 2019. The main characteristics and prognostic data of each eligible study were extracted. The odds ratio (OR) for the overall response rate (ORR) and hazard ratio (HR) for progression-free survival (PFS) were estimated using the fixed-effects Mantel-Haenszel model. RESULTS: A total of 8 studies involving 2670 patients were included for analysis. Overall, the clinical outcomes of PI3K inhibitors were significantly influenced by PIK3CA mutation status in HR+ breast cancer. After the treatment of PI3K inhibitors, HR+ breast cancer patients with PIK3CA mutations presented better ORR (PIK3CA-mutated group: OR = 1.98 [95% CI, 1.46 to 2.70]; PIK3CA wild-type group: OR = 1.09 [95% CI, 0.78 to 1.53]) and better PFS (PIK3CA-mutated group: HR = 0.65 [95% CI, 0.55 to 0.76]; PIK3CA wild-type group: HR = 0.87 [95% CI, 0.70 to 1.09]). No publication bias was detected for ORR and PFS in our analysis. CONCLUSION: In this meta-analysis, it suggests that the association between clinical outcomes of PI3K inhibitors and PIK3CA mutation status is dramatic. PIK3CA mutations were a favorable factor in the clinical outcomes of HR+ breast cancer treated with PI3K inhibitors.