Predictive Role of Serum Inflammatory Markers in Metastatic Luminal A/B Breast Cancers Receiving CDK‐4/6 Inhibitors Therapy

BACKGROUND: We conducted this study to evaluate the impact of serum inflammatory markers and histopathological features on prognosis in metastatic hormone receptor positive breast cancer patients treated with first line CDK4/6i (cyclin-dependent kinase inhibitors). OBJECTIVES: While serum markers are better indicators in triple-negative and HER-2 positive breast cancers, the PFS (progression-free survival) durations of NLR (neutrophil/lymphocyte ratio), PLR (platelet/lymphocyte ratio), and LMR (platelet/lymphocyte ratios) in luminal A-B group patients vary between studies. In our study investigated whether baseline NLR, PLR, and LMR have a predictive value for PFS in hormone-positive metastatic breast cancer receiving CDK4/6i. MATERIAL AND METHODS: The study included 111 patients with de novo metastasis or recurrence/metastasis after adjuvant/neo-adjuvant treatment who received CDK-4/6i as first-line therapy. NLR, PLR, LMR, lymphocyte, neutrophil, and monocyte values were recorded from peripheral blood analyses before CDK-4/6i treatment. RESULTS: When the patient characteristics of patients were analyzed for progression-free survival, no statistically significant differences were found between age, ECOG, grade, Ki-67 index, and menopause status. PFS was not significantly associated with NLR, PLR, and LMR values (p = 0.87, p = 0.51, p = 0.22, respectively. In univariate analysis, among patients with LMR > 3.48, ribociclib was associated with longer PFS than palbociclib. Multivariate analysis revealed that the luminal B molecular subtype was associated with significantly worse PFS compared to luminal A (23 vs. 43 months, respectively, p = 0.01). CONCLUSIONS: The prognostic impact of serum inflammatory markers in hormone receptor-positive metastatic breast cancer is heterogeneous. Although no statistical significance was observed in our cohort, high LMR levels may provide predictive and prognostic value in treatment selection.