25-hydroxyvitamin D levels and survival in patients with advanced pancreatic cancer (APC): Findings from CALGB 80303.

Abstract

4022 Background: Data from animal and cell line models suggest that vitamin D metabolism is important in pancreatic tumor maintenance and may contribute to this tumor’s chemoresistance. While vitamin D has been implicated in a variety of cancers, the prevalence of vitamin D deficiency among patients with advanced pancreatic cancer (APC) and the effect of baseline vitamin D levels on survival outcomes are unknown. Methods: CALGB 80303 was a randomized controlled trial of patients with APC which demonstrated no difference in OS among patients treated with gemcitabine (GEM) vs. GEM + bevacizumab. We retrospectively measured baseline serum 25(OH)D levels and examined associations between baseline 25(OH)D levels and selected patient characteristics. Using the Cox rank score test, we examined the association between 25(OH)D level and PFS and OS. The differences in the levels among racial populations were tested using the Kruskal-Wallis test. Results: Of 256 patients with available serum, the median 25(OH)D level was 21.7 (range 4–77). 44.5% of patients were vitamin D deficient (25(OH)D <20), 32.4% were insufficient (25(OH)D ≥20 and <30), and 23% were sufficient (25(OH)D≥30). Serum 25(OH)D levels were lower in patients self-reported as black compared to white patients and patients of other/undisclosed race (median 10.7 [4.0–36.3] vs. 22.4 [4.0–77.0] vs. 20.9 [12.6 – 31.8], respectively; p<0.00001). Adjusting for race, baseline 25(OH)D levels were not associated with PFS (HR 1.00, 95% CI 0.98–1.01) or OS (HR 1.00, 95% CI 0.99-1.01). Conclusions: Vitamin D deficiency was highly prevalent among patients with a new diagnosis of APC. Black patients had significantly lower 25(OH)D levels than white patients. In this cohort of patients with APC receiving GEM-based chemotherapy, baseline 25(OH)D levels were not associated with PFS or OS.