Pretreatment Platelet Count and Neutrophil/Lymphocyte Ratio Are Predictive Markers for Carboplatin Plus Pemetrexed Therapy-induced Thrombocytopenia

Abstract

Background/Aim: This study aimed to identify the predictive markers for carboplatin-induced severe thrombocytopenia. Patients and Methods: We conducted a retrospective cohort analysis of inpatients who received carboplatin and pemetrexed. Results: Among the 106 eligible patients, the incidence rate of grade ≥3 thrombocytopenia was 29.2% (31/106). Multivariate analysis revealed that grade ≥3 thrombocytopenia was associated with platelet count ≤26.6×10⁴/mm³ [odds ratio (OR)=24.70, 95% confidence interval (CI)=5.75-106.00; p<0.001], neutrophil/lymphocyte ratio (NLR) >2.856 (OR=15.10, 95%CI=2.89-78.60; p=0.0013) and prognostic nutritional index ≤42.511 (OR=6.25, 95%CI=1.53-25.60; p=0.011). In particular, patients with both platelet counts ≤26.6×10⁴/mm³ and NLR >2.856 presented with significantly higher frequencies of thrombocytopenia compared to those without these two factors [23/34 patients (67.6%) vs. 8/72 patients (11.1%), OR=16.1, 95%CI=5.40-53.6; p<0.001]. Conclusion: Platelet counts ≤26.6×10⁴/mm³ and NLR >2.856 are predictive markers for carboplatin-induced thrombocytopenia.