Vitamin D status and survival in patients with triple negative breast cancer.

Abstract

e18210 Background: Although many studies have investigated the association of blood 25OH-vitamin D (vit-D) levels with breast cancer prognosis, the results have been mixed. It has been suggested that low vit-D concentrations were associated with advanced tumor stage and triple-negative (TNBC) subtype. We retrospectively investigated associations of serum vit-D levels with triple negative breast cancer outcome. Methods: Out of 797 cases of TNBC diagnosed at William Beaumont Hospital between 2006-2017, 163 patients had vit-D level available within 1 year prior to diagnosis. Analyses of vit-D levels was classified by 3 cut points (deficient, < 20.0 ng/mL; insufficient, 20.0-29.9 ng/mL; sufficient, ≥30.0 ng/mL). Primary outcomes are disease free survival (DFS) and overall survival (OS). SPSS statistics 25 software was used to analyze the data. Results: Median age of diagnosis of TNBC was 60. Of these patients 43.6% were diagnosed with stage I, 37.4% at stage II, 4.9% at stage III and 4.9% at stage IV. 47.2% of the patients had sufficient vit-D level prior to diagnosis, 28.2% with insufficient vit-D level and 24.5% with deficient vit-D. Vit-D deficiency was more prevalent in premenopausal than in postmenopausal women (33.3%, 41% and 25.6% in premenopausal women for deficient, insufficient and sufficient levels respectively vs 21.8%, 24.2% and 54% in postmenopausal women). Rates of Vit-D deficiency were not different between early disease and advanced disease (24.3% of patient with stage I-II vs 25% in patients with stage III-IV). Median OS and disease-free survival were not statistically different among the 3 different categories. 5-year OS was 91%, 91% and 85% for deficient, insufficient and sufficient levels respectively. 5-year DFS was 93%, 95% and 95% for deficient, insufficient and sufficient levels respectively. Multivariate COX regression analysis demonstrated that age and stage were associated with mortality, whereas vit-D level was not. Conclusions: The results from this study show that adequate vit-D level do not have an impact on OS and DFS in patients with triple negative breast cancer. Premenopausal women are more likely to have inadequate vit-D level. Identification and treatment of vitamin D deficiency is still important for musculoskeletal health and possibly extraskeletal health in general population and breast cancer survivors specifically.