Prognostic value of neutrophil to lymphocyte ratio in lung metastasectomy for colorectal cancer.

Objectives: Neutrophil to lymphocyte ratio (NLR) has been shown to be a promising biomarker in several cancers. Prognostic biomarkers are still needed to define good candidates for lung metastasectomy for colorectal cancer. We aimed to evaluate the role of NLR.

Methods: Data from 574 patients who underwent lung metastasectomy for colorectal cancer in 3 departments of thoracic surgery from 2004 to 2014 were retrospectively reviewed. Overall survival (OS) and the time to pulmonary recurrence (TTPR) were the main end points.

Results: Correlations between NLR and OS (R2 = 0.53), and NLR and TTPR (R2 = 0.389) were significant (P < 0.0001 for both), with corresponding Pearson R of -0.728 (P < 0.0001) and -0.624 (P < 0.0001), respectively. A receiver operating characteristic curve analysis highlighted an NLR cut-off value of 4.05 as the best predictor of OS and TTPR. NLR ≤4.05 was observed in 238 patients (41.4%). In the univariable analysis, the median OS was 117 months for patients with NLR ≤4.05 and decreased to 40 months for patients with NLR >4.05 (P < 0.0001). The median TTPR reached 52 months in case of NLR ≤4.05 and decreased to 12 months in patients with NLR >4.05. In the multivariable analysis, NLR ≤4.05 remained an independent favourable prognostic factor on both OS [hazard ratio [HR] 0.29, 95% confidence interval (CI) 0.167-0.503; P < 0.0001] and TTPR (HR 0.346, 95% CI 0.221-0.54; P < 0.0001). Significant correlations between NLR >4.05 and KRAS (Cramer's V = 0.241, P < 0.0001) and BRAF (Cramer's V = 0.153, P = 0.003) mutations were observed.

Conclusions: NLR is a simple and powerful predictor of outcomes in patients undergoing pulmonary metastasectomy for colorectal cancer.