Serum 25-hydroxyvitamin D levels in early and advanced breast cancer.

BACKGROUND Laboratory and epidemiological studies have implicated vitamin D deficiency in the pathogenesis of breast cancer. 1,25-Dihydroxyvitamin D (1,25(OH)(2)D) promotes differentiation and apoptosis, and potently inhibits proliferation of malignant breast epithelial cells in culture. Serum levels of 1,25(OH)(2)D are higher in normal women than in patients with primary breast cancer. AIM To clarify the role of vitamin D in breast cancer progression by comparing the levels of serum vitamin D in patients with early and in those with advanced breast cancer. METHODS Circulating levels of 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and calcium were measured prospectively in 279 Caucasian women with invasive breast cancer, 204 women with early-stage disease and 75 women with locally advanced or metastatic disease. RESULTS Patients with early-stage breast cancer had significantly higher circulating levels of 25(OH)D (p<0.005) and significantly lower PTH (p<0.001) levels than those with advanced disease. Calcium levels did not differ significantly (p = 0.74). CONCLUSION Serum levels of 25(OH)D are significantly higher in patients with early-stage breast cancer than in those with locally advanced or metastatic disease.