Prognostic evaluation of vitamin D deficiency in breast cancer patients: a pilot study in India.

Background : Vitamin D deficiency has been associated with poor prognosis in breast cancer. A new molecular classification of breast cancer is being increasingly used that is based on expression of estrogen receptors, progesterone receptors and Her2/neu amplification and is found to correlate well with prognosis and outcome of disease. The present study was designed to determine serum vitamin D deficiency in these molecular subtypes of breast cancer. Methods:   Estimation of serum vitamin D levels by chemiluminiscence was done in a cohort of 99 breast cancer patients and 25 age matched healthy controls. Breast cancer patients were further grouped into luminal A, luminal B, Her2/neu enriched and triple negative subtypes based on immunohistochemistry results. Non-parametric tests were performed to compare vitamin D levels in different groups. Results:  54.6%, 60%, 66.6% and 84.2% of patients with luminal A, luminal B, Her2/neu enriched and triple negative subtypes respectively were found to be vitamin D deficient (<20ng/mL) as compared to only 20% in healthy controls. More aggressive Her2/neu enriched and triple negative subtype patients had significantly lower serum vitamin D levels than the luminal subtypes of breast cancer.  Conclusion: Vitamin D deficiency is more prevalent and significantly lower levels are found in more aggressive subtypes of breast cancer. Vitamin D supplementation must be considered in these forms of breast cancer to improve outcome.