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Vitamin D and Breast Cancer Prognosis

4/25/2017 11:24:42 AM
Experimental studies have demonstrated biological plausibility of vitamin D as an immune-modulating and anticancer agent. Epidemiological studies examining the relationship between vitamin D status and risk of initial breast cancer occurrence have produced mixed results, but there is sound evidence that low serum vitamin D levels correlate with advanced tumor stage and triple-negative subtype at diagnosis. The relationship between vitamin D status and breast cancer prognosis was the subject of the study reviewed here.
 
This case-cohort study, published by Yao et al in JAMA Oncology (2016), selected 1666 woman from the Pathways Study, a prospective study initiated in 2006 of women with newly diagnosed invasive breast cancer. Women were evaluated approximately 2 months after breast cancer diagnosis for serum 25(OH)D levels and have been followed at regular intervals since that time. Primary outcome measures for the current analysis were breast cancer recurrence, second primary cancer, and death.
 
Consistent with previous studies, women with advanced-stage tumors or triple-negative cancer had the lowest serum 25(OH)D levels. After adjusting for tumor stage, grade, and clinical subtype as well as other nonclinical factors, women in the highest tertile of 25(OH)D levels had superior overall survival when compared with women in the lowest tertile of 25(OH)D levels (HR=0.72; 95% CI, 0.54-0.98; p=.03 for trend). The association was stronger in premenopausal women, who also had significantly better breast cancer-specific survival, recurrence-free survival, and invasive disease-free survival if in the highest tertile of 25(OH)D levels.
 
The cut-off value for serum 25(OH)D was less than 16.75ng/mL for the lowest tertile and more than 25.10ng/mL for the highest tertile. The results of this study suggests that serum levels of 25(OH)D greater than 25ng/mL may offer prognostic benefit in patients with incident invasive breast cancer.
 
Reference: Yao S, Kwan ML, Ergas IJ, et al. Association of Serum Level of Vitamin D at Diagnosis With Breast Cancer Survival: A Case-Cohort Analysis in the Pathways Study. JAMA Oncol. 2016