Pretreatment neutrophil-to-lymphocyte ratio as an important prognostic marker in stage III locally advanced non-small cell lung cancer: Confirmatory results from the PROCLAIM phase III clinical trial

Background: Neutrophil-to-lymphocyte ratio (NLR) is an important pretreatment marker of systemic inflammation and tumor aggressiveness. Increased levels of this ratio have been associated with reduced survival in several observational studies of lung cancer. However, supporting analyses from large clinical trial data are lacking. Methods: To validate the prognostic role of NLR, the current study evaluated data from a randomized phase III study (PROCLAIM; clinicaltrial.gov ID: NCT00686959) of patients with stage IIIA/B, unresectable, non-squamous, non-small cell lung cancer (NSCLC), originally comparing combination pemetrexed-cisplatin chemoradiotherapy with etoposide-cisplatin chemoradiotherapy. Adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for survival were estimated using a Cox proportional hazards model. Models were adjusted for age, race, sex, stage, treatment, and body mass index (BMI). Patients were followed for a median of 24 months. Results: Increased NLR levels at baseline were associated with reduced overall (P_Trend <0.0001) and progression-free survival (P_Trend <0.005). A similar but decreasing linear trend was not observed for lymphocytes count alone. Conclusions: These findings provide substantiating evidence that NLR, which is routinely available from standard blood testing of patients diagnosed with NSCLC, is an important inflammation-based prognostic marker for survival among patients with locally advanced disease undergoing chemoradiation. Future research will benefit by assessing the prognostic potential of NLR in the context of genetic mutations and molecular markers.