Circulating 25-hydroxyvitamin D level and prognosis of lung cancer patients: A systematic review and meta-analysis

Background > Previous studies suggested a possible influence of circulating 25-hydroxyvitamin D [25(OH) D] level on the prognosis of lung cancer patients, but conflicting findings were reported. A systematic review and meta-analysis was thus conducted to comprehensively assess the influence of circulating 25(OH) D level on the prognosis of lung cancer patients. Methods > Prospective or retrospective cohort studies assessing the influence of circulating 25(OH) D level on the prognosis of lung cancer patients were considered eligible. Hazard Ratios (HR) were pooled using meta-analysis. Results > Eight studies with 2166 lung cancer patients were included. Meta-analysis of unadjusted HRs from four studies showed low circulating 25(OH) D level was significantly correlated with poor overall survival in lung cancer (HR = 1.30, 95% CI 1.08-1.55, P = 0.004). Meta-analysis of adjusted HRs from eight studies suggested that low circulating 25(OH) D level was not significantly correlated with poor overall survival (HR = 1.25; P = 0.13). However, sensitivity analysis suggested an obvious change in the pooled HRs when excluding single study by turns. When the study by Liu et al. was omitted, low circulating 25(OH) D level was significantly correlated with poor overall survival (HR = 1.34; P = 0.04). Conclusion > The present systematic review and meta-analysis suggested a correlation between low circulating 25(OH) D level and poor overall survival in lung cancer. More studies are needed to further validate the finding above.