Serum Vitamin D Levels Affect Pathologic Complete Response in Patients Undergoing Neoadjuvant Systemic Therapy for Operable Breast Cancer

Abstract

The impact of serum vitamin D levels on rate of pathologic complete response (pCR) after neoadjuvant chemotherapy in 144 patients with operable breast cancer was retrospectively investigated. Low serum vitamin D levels were associated with not attaining a pCR. Further study of vitamin D supplementation as a means to improve pCR rates is warranted. Introduction: There has been increasing interest in the potential benefit of vitamin D in improving breast cancer outcome. Preclinical studies suggest that vitamin D enhances chemotherapy-induced cell death. We investigated the impact of serum vitamin D levels during neoadjuvant chemotherapy (NAC) on the rates of achieving pathologic complete response (pCR) after breast cancer NAC. Patients and Methods: Patients from 1 of 2 Iowa registries who had serum vitamin D level measured before or during NAC were included. French patients enrolled onto a previous study of the impact of NAC on vitamin D and bone metabolism were also eligible for this study. Vitamin D deficiency was defined as < 20 ng/mL. pCR was defined as no residual invasive disease in breast and lymph nodes. A Firth penalized logistic regression multivariable model was used. Results: The study included 144 women. There was no difference between the French and Iowan cohorts with regard to age at diagnosis (P =.20), clinical stage (P =.22), receptor status (P =.32), and pCR rate (P =.34). French women had lower body mass index (mean 24.8 vs. 28.8, P