PIK3CA and neoplasm: The present analysis showed that combination therapy would prolong PFS for postmenopausal patients with PIK3CA-mutant ctDNA (HR = 0.52, 95%CI: 0.39–0.69), whereas patients with PIK3CA mutation detected in tumor issue failed to show the significant benefit (HR = 0.70, 95%CI: 0.48–1.02).