Serum levels of 25-hydroxyvitamin D at diagnosis are not associated with overall survival in esophageal adenocarcinoma

Background: Higher levels of circulating 25-hydroxyvitamin D [25(OH)D] are associated with longer survival in several cancers, but the results have differed across cancer sites. The association between serum 25(OH)D levels and overall survival (OS) time in esophageal adenocarcinoma remains unclear. Methods: We utilized serum samples from 476 patients with primary esophageal adenocarcinoma, recruited from Massachusetts General Hospital (Boston, MA) between 1999 and 2015. We used log-rank tests to test the difference in survival curves across quartiles of 25(OH)D levels and extended Cox modeling to estimate adjusted HRs. We tested for interactions between clinical stage or BMI on the association between 25(OH)D and OS. We additionally performed sensitivity analyses to determine whether race or timing of blood draw (relative to treatment) affected these results. Results: We found no evidence that survival differed across quartiles of 25(OH)D (log rank P = 0.48). Adjusting for confounders, we found no evidence that the hazard of death among the highest quartile of 25(OH)D (quartile 1) differed from any other quartile [quartile 2 HR = 0.90, 95% confidence interval (CI), 0.67-1.23; quartile 3 HR = 1.03, 95% CI, 0.76- 1.38; quartile 4 (lowest) HR = 0.98, 95% CI, 0.72-1.33]. Sensitivity analyses yielded consistent results when accounting for race or time between diagnosis and blood draw. Moreover, we did not find evidence of interaction between 25(OH)D and clinical stage or BMI on OS. Conclusions: Serum level of 25(OH)D near time of diagnosis was not associated with OS in patients with esophageal adenocarcinoma. Impact: Screening 25(OH)D levels among patients with esophageal adenocarcinoma at diagnosis is not clinically relevant to their cancer prognosis based on present evidence.