Vitamin D Supplementation During Neoadjuvant Chemotherapy for Breast Cancer Improves Pathological Complete Response: A Prospective Randomized Clinical Trial.

INTRODUCTION

Achieving a pCR serves as a biomarker indicating enhanced overall survival for breast cancer patients undergoing NST. Vitamin D enhances the antitumor effect of chemotherapeutics as demonstrated in cancer cells and animal models. In this prospective randomized clinical study, we aim to investigate the effect of oral vitamin D supplementation during neoadjuvant systemic therapy (NST) on pathologic complete response (pCR).

METHODS

Between June 2019 and June 2023, an oral form of 50,000 IU vitamin D3 (cholecalciferol) replacement was administered once a week during NST for the study group.

RESULTS

There were 114 (50.2%) cases in the study group and 113 (49.8%) in the control group (totally 227 cases). Factors that positively influenced pCR were higher clinical T stage, higher AJCC clinical stage, Estrogen receptor negativity, progesterone receptor negativity, human epidermal growth factor receptor 2 positivity, high Ki-67 expression (≥ 20%), hormone negative molecular subtypes, and vitamin D intake in univariate analysis. In the multivariate analysis, factors significantly affecting pCR were vitamin D intake (OR: 2.33, 95% CI 1.20-4.53; p = 0.013), hormone receptor negativity (OR: 2.22, 95% CI 1.11-4.43; p = 0.024), and Ki-67 ≥ 20% (OR: 3.27, 95% CI 1.03-10.34; p = 0.044).

CONCLUSIONS

This is the first and only study to compare the effect of oral vitamin D supplementation on pCR during NST. Vitamin D supplementation during NST has a significant effect on pCR in breast cancer patients. Although this effect is not significant for axillary pCR, there is an almost significant correlation.

TRIAL REGISTRATION

ClinicalTrials.gov (Identifier: NCT03986268).