Neutrophil to Lymphocyte Ratio in Lung Cancer: Implications for Depressive Symptoms and Survival

BACKGROUND: Depression very commonly appears in the presence of lung cancer. Multiple contexts have shown that depression is associated with inflammation. The Neutrophil to Lymphocyte Ratio (NLR) provides an easy to interpret the measure of both inflammation and immunity, but its use as an inflammatory biomarker has not been evaluated in patients with lung cancer. We hypothesize that NLR will be elevated in depressed patients with lung cancer and that both elevated NRL and depression will have prognostic implications. METHODS: Patients (n=109) were assessed for depression and anxiety using the Hospital .Anxiety and Depression Scale (HADS) and for distress using the Distress Thermometer. NLR was derived from a complete blood count obtained on the day of the cross-sectional survey. Data were dichotomized (NLR ≥5 and HADS-D ≥8) and analysed for survival estimations using Kaplan-Meier plots. RESULTS: NLR was found to be significantly correlated with depression (r=.21, p=.03) and was associated with depression while controlling for age, sex, and marital status (β=.21, p=.004). NLR trended toward correlation with anxiety (r=.19, p=.07). Elevated NLR (≥5) predicted for worse survival (chi square= 10.08, p=.001), which was similarly seen when combined with meeting depression criteria (chi square = 16.00,p<.001). CONCLUSION: NLR provides a reasonable assessment of lung cancer related inflammation with survival implications that may indicate the presence of depression. These results warrant further research.