Auhtors: Ng K, Venook AP, Sato K, Yuan C, Hollis BW, Chang IW, et al.
doi: https://doi.org/10.1200/jco.2015.33.15_suppl.3503
Abstract
Background: Prospective epidemiologic data suggest that higher levels of 25-hydroxyvitamin D [25(OH)D] are associated with improved survival in patients with colorectal cancer, however the relationship between 25(OH)D and outcome in metastatic CRC (mCRC), specifically, is unknown. Methods: We prospectively assessed the association between plasma 25(OH)D and overall survival (OS) in previously untreated mCRC patients enrolled in CALGB/SWOG 80405, a randomized phase III trial of chemotherapy + bevacizumab, cetuximab, or both, prior to the KRAS wild type amendment. Progression-free survival (PFS) was a secondary endpoint. Plasma 25(OH)D levels were measured at baseline by radioimmunoassay, and dietary and lifestyle behaviors collected from self-administered questionnaires. Cox proportional hazards models were used to calculate hazard ratios (HR) adjusted for other prognostic variables. Results: Among 1,043 patients, median plasma 25(OH)D was 17.2 ng/mL (range 2.2-72.7). Male and black patients, those living in the northeast, patients with lower dietary and supplemental vitamin D intake, ECOG performance status 1 (vs. 0), tumoral RAS mutation, higher body-mass index, lower physical activity, and blood draw during the winter and spring had significantly lower levels of 25(OH)D. Patients in the highest quintile of 25(OH)D had significantly improved OS compared to those in the lowest after adjusting for pathologic and clinical prognostic factors (median 32.6 vs. 24.5 months; HR 0.65, 95% CI, 0.51-0.83; P trend = 0.001). Increasing concentrations of 25(OH)D were also significantly associated with improved PFS (median 12.2 vs. 10.1 months; HR 0.79, 95% CI, 0.63-0.99; P trend = 0.01). The results were consistent across subgroups of patient characteristics, including RAS status, and remained unchanged after excluding patients who died within 3 or 6 months of blood draw. Conclusions: Higher concentrations of plasma 25(OH)D are associated with significantly improved survival in mCRC patients treated with chemotherapy + biologics. Randomized trials of vitamin D supplementation are warranted and ongoing, and effect modification by SNPs in vitamin D pathway genes is currently being explored.
Source: https://ascopubs.org/doi/10.1200/jco.2015.33.15_suppl.3503
Archive: https://archive.is/eLlR1
