Pretreatment neutrophil-to-lymphocyte ratio as a survival predictor for small-cell lung cancer

The inflammatory response indexes, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), have prognostic value for a variety of cancers. However, their prognostic value for small-cell lung cancer (SCLC) has been rarely reported. In this study, we monitored changes of NLR and PLR along with the clinical outcomes in patients with limited-stage and extensive-stage SCLC who received standard treatments.

We retrospectively reviewed the records of 153 patients who were pathologically diagnosed with SCLC and collected their hematological data at different time points during disease and treatment process. Kaplan-Meier analysis and Cox proportional hazards models were used to determine the prognostic significance of NLR and PLR for overall survival (OS) and progression-free survival (PFS).

The median OS and PFS for all patients were 23.3 months and 11.0 months, respectively. After applying cutoffs of 3.2 for NLR and 122.7 for PLR, NLR, but not PLR, showed independent prognostic significance. High-NLR group was associated with shorter median OS (high vs low, 18.0 months vs 31.0 months, P<0.01) and shorter PFS (high vs low, 9.3 months vs 13.0 months, P=0.006). The cumulative 3-year OS rate and 3-year PFS rate of high-NLR group versus low-NLR group were 14.3% versus 37.3% and 8.6% versus 22.9%, respectively. In the multivariate analysis, both disease stage and NLR at diagnosis were independent prognostic factors for OS and PFS.

The NLR at diagnosis showed significant prognostic value for clinical outcomes in SCLC patients treated with chemoradiotherapy. As an effective biomarker of host immune status, NLR could potentially help monitoring disease progression and adjusting treatment plans.