The cumulative results indicate that the neutrophil to lymphocyte ratio of peripheral blood (pbNLR) is a useful prognostic factor in patients with various cancers. In contrast to peripheral blood, the bronchoalveolar lavage (BAL) fluid is in direct contact with the lung lesion. However, no study has reported on the clinical utility of the NLR of BAL fluid (bNLR) for patients with lung cancer. To investigate the clinical utility of the bNLR as a prognostic factor in patients with lung cancer, we conducted a retrospective review of the prospectively collected data. A total of 45 patients were classified into high bNLR (n = 29) and low bNLR (n = 16) groups. A high pbNLR and high bNLR were associated with a shorter overall survival (p p = 0.011, respectively). A multivariable analysis confirmed that ECOG PS (p = 0.023), M stage (p = 0.035), pbNLR (p = 0.008), and bNLR (p = 0.0160) were independent predictors of overall survival. Similar to the pbNLR, a high bNLR value was associated with a poor prognosis in patients with lung cancer. Although further studies are required to apply our results clinically, this is the first study to show the clinical value of the bNLR in patients with lung cancer.
