The role of vitamin D in cancer care was the subject of considerable attention at the recent Society for Integrative Oncology 7th annual assembly. Researchers and clinicians gathered at the meeting seemed to be moving toward a consensus that high-dose vitamin D supplementation has potential to markedly reduce risk of primary breast cancer as well as breast cancer recurrence, with minimal risk of toxicity. Data presented at the meeting—held just two weeks before the Institute of Medicine’s November 30 consensus statement dismissing the potential of vitamin D beyond bone health—indicate that women with serum levels under 20 ng/ml are at significantly increased risk, that raising levels to 50 ng/ml mitigates that risk, and that oral doses upwards of 10,000 IU/day are safe for women at risk of breast cancer.