Polymorphisms of Vitamin D Receptor and Survival in Early-Stage Non–Small Cell Lung Cancer Patients

Abstract

Our previous analysis suggested that surgery season in the summer time and high vitamin D intake are associated with improved survival in early-stage non-small cell lung cancer (NSCLC) patients. Here, we investigated the associations of vitamin D receptor (VDR) polymorphisms of Cdx-2 G>A, FokI C>T, and BsmI C>T with overall survival (OS) and recurrence-free survival (RFS) in 373 early-stage NSCLC patients. The data were analyzed using log-rank test and Cox proportional hazards models. The median follow-up time was 71 months (range, 0.1-140 months), with 186 deaths and 127 recurrences. There was no association between VDR polymorphisms and survival, overall or among adenocarcinoma patients. Among squamous cell carcinoma (SCC) patients, the G/A+A/A genotype group of the Cdx-2 polymorphism was associated with better OS: the 5-year OS rates were 41% [95% confidence interval (95% CI), 28-53] for the G/G and 55% (95% CI, 39-71) for the G/A+A/A genotypes, respectively (P = 0.04, log-rank test), with the adjusted hazard ratio of 0.56 (95% CI, 0.33-0.95) for G/A+A/A versus G/G. For the joint effects of the three polymorphisms, subjects with two or more "protective" alleles have better OS among SCC patients, with the adjusted hazard ratios of 0.20 (95% CI, 0.09-0.48), 0.40 (95% CI, 0.19-0.87), and 0.43 (95% CI, 0.19-0.97), respectively, for subjects with two, three, and four or more "protective" alleles when compared with subjects with zero or one "protective" allele (P(trend) = 0.71). Similar associations were found in haplotype analysis and for RFS among SCC patients. In conclusion, VDR polymorphisms may be associated with improved survival among SCC patients of early-stage NSCLC.