PURPOSE: We investigated the changes in serum 25-hydroxyvitamin D (25[OH]D) levels before and after neoadjuvant chemotherapy (NCT) and the associations with pathologic complete response (pCR) and survival in patients with breast cancer. METHODS: Serum 25(OH)D concentrations were measured pre- and post-NCT in 374 patients between 2010 and 2013. Based on a cutoff of 20 ng/mL, patients were categorized into “either sufficient” or “both deficient” groups. The associations with clinicopathological data, including pCR and survival, were analyzed using multivariable analyses. RESULTS: Patients with either pre- or post-NCT sufficient 25(OH)D levels accounted for 23.8%, and the overall pCR rate was 25.9%. Most patients showed 25(OH)D deficiency at diagnosis and 65.8% showed decreased serum levels after NCT. Changes in 25(OH)D status were associated with postmenopause status, rural residence, baseline summer examination, and molecular phenotype, but not pCR. No association between survival and 25(OH)D status was found, including in the subgroup analyses based on molecular phenotypes. CONCLUSION: Most Korean patients with breast cancer showed vitamin D deficiency at diagnosis and a significant decrease in the serum concentration after NCT. No association with oncologic outcomes was found. Therefore, although optimal management for vitamin D deficiency is urgent for skeletal health, further research is warranted to clearly determine the prognostic role of vitamin D in patients with breast cancer who are candidates for NCT.
Breast Neoplasms* ; Breast* ; Diagnosis ; Drug Therapy* ; Humans ; Neoadjuvant Therapy ; Phenotype ; Polymerase Chain Reaction ; Postmenopause ; Treatment Outcome ; Vitamin D ; Vitamin D Deficiency