Effect of Vitamin D Supplementation on Chemotherapy Side Effects After Adjuvant Chemotherapy for Breast Cancer

This is a parallel group, open-label randomized controlled trial to investigate the occurrence of side effects of vitamin D supplementation (VD) in adjuvant chemotherapy in patients with breast cancer. Both groups will receive standard adjuvant chemotherapy on day 1 and each subsequent cycle. In addition, vitamin D2 will be given randomly to both groups. Blood samples and imaging results were collected and analyzed before initiation of adjuvant chemotherapy and after every two cycles. The primary outcome to be documented was associated grade III or higher adverse events during adjuvant chemotherapy. Primary and secondary study findings and adverse events will be thoroughly evaluated.