Background: Small cell lung cancer (SCLC) is a special type of lung cancer and it is responsive to chemotherapy. Blood parameters have been proved to be associated with survival for many types of malignancies. This study aimed to investigate the prognostic significance of platelet-to-lymphocyte ratio (PLR) and mean platelet volume (MPV) for SCLC patients with etoposide-based first-line treatment.
Methods: We retrospectively identified 138 patients diagnosed as SCLC who underwent etoposide-based first-line chemotherapy. The patients’ baseline clinical characteristics and blood parameters were collected. Kaplan–Meier analysis and Cox regression methods were used to determine the factors associated with progression-free survival (PFS).
Results: The optimal cut-off value of diagnosis was depended on the ROC curve, the cut-off value of pretreatment PLR was 190 (sensitivity 39.0%, specificity 88.5%), and the cut-off value of pretreatment MPV was 10.0 (sensitivity 60.7%, specificity 61%). Kaplan–Meier analysis showed patients with high PLR levels in baseline had worse PFS than those with low PLR levels (P  <0.001). Multivariate analysis revealed pretreatment MPV was an independent prognostic factor for PFS (HR: 0.815, 95% CI: 0.711–0.933, P =0.003). Further research suggested continuous high PLR indicated a poor therapy outcome (P  =0.002).
Conclusion: Pretreatment MPV can be an independent predictor for first-line treatment outcome and a continuously high level of PLR suggested inferior PFS in etoposide-treated SCLC patients.
Keywords: small cell lung cancer, SCLC, first-line chemotherapy, mean platelet volume, MPV, platelet-to-lymphocyte ratio, PLR, prediction