Clinical value of circulating mutations for patients with metastatic breast cancer: a meta-analysis.

BACKGROUND

The clinical implication of plasma ESR1 mutations in the estrogen receptor (ER)-positive metastatic breast cancer (MBC) patients who had progressed after prior aromatase inhibitor (AI)-based therapy remains controversial. We conducted the first meta-analysis to investigate the prognostic significance and predictive role of plasma ESR1 mutations in MBC patients with prior exposure to AI therapy.

MATERIALS AND METHODS

We searched PubMed, Embase, and Cochrane Library databases for eligible studies. Meta-analysis was conducted to calculate combined hazard ratios (HRs) with 95% CIs for progression-free survival (PFS) and overall survival (OS). Subgroup and sensitivity analyses were also performed.

RESULTS

This study enrolled a total of 1,530 patients with ER-positive MBC cases from six articles, including 429 ESR1 mutation carriers (28.04%). Meta-analysis demonstrated that plasma ESR1 mutation carriers had significantly worse PFS (HR: 1.40, 95% CI: 1.17-1.66; <0.0001) and OS (HR: 1.65, 95% CI: 1.36-2.01; <0.0001) compared to wild-type ESR1. Subgroup analysis showed that plasma ESR1 mutations were associated with shorter PFS after AI-based treatment, but were not significantly predictive of outcome on fulvestrant-containing therapy (HR: 1.26, 95% CI: 0.98-1.62; =0.077). As for different ESR1 mutations, D538G mutation implied significantly worse PFS (HR: 1.50, 95% CI: 1.18-1.91; =0.01), while Y537S mutation was not correlated with PFS (HR: 1.65, 95% CI: 0.87-1.73; =0.134).

CONCLUSION

The meta-analysis indicated that plasma ESR1 mutation assessment may have prognostic significance and clinical value in guiding further endocrine therapy choice in ER+ MBC patients who received prior AI therapy.