Prognostic Significance of Serum Vitamin D Levels in Egyptian Females with Breast Cancer

Objective: To determine the frequency and prognostic significance of vitamin D deficiency in Egyptian women with breast cancer (BC). Methods: This prospective study included 50 women with primary invasive, non-metastatic BC. The serum level of 25-hydroxy vitamin D [25(OH)D was measured by ELISA at diagnosis, before any cancer treatment. Vitamin D deficiency was defined as 25(OH) D<20 ng/mL. Patients were followed up for a median of 30 months (range: 18-48). Results: The median level of 25(OH)D was 29.0 ng/mL (range: 10.0-55.0 ng/mL). Fifteen patients (30%) had vitamin D deficiency, which was positively associated with larger tumor size (p < 0.001), higher grade (p = 0.014), advanced stage (p = 0.001), lymph node positivity (p = 0.012), and HER2/neureceptor expression (p = 0.002). It was also linked with worse overall survival (OS) and disease free survival (DFS) (p = 0.026, and p = 0.004, respectively). On multivariate analysis, DFS was independently affected by vitamin D deficiency with an HR of 2.8 (95% CI: 1.6-7.0, p = 0.022) and advanced stage, i.e. stage II had worse survival compared to stage I with an HR of 4.8 (95%CI: 1.1-21.7, p = 0.042). Conclusion: Vitamin D deficiency had a negative effect on overall and disease-free survival in our breast cancer cases, being related to tumor size, stage, grade, nodal status and HER2/neu receptor expression.