Vitamin D Insufficiency Linked to Aggressive Breast Tumors

Pam Harrison

May 09, 2011

May 9, 2011 (Washington, DC) — Breast cancer patients with suboptimal vitamin D levels are more likely to have more aggressive tumors and worse prognostic markers than those with adequate vitamin D levels.

Kristin Skinner, MD, from the University of Rochester Medical Center in New York, presented the results of a study here at the American Society of Breast Surgeons (ASBS) 12th Annual Meeting. Researchers found that vitamin D deficiency is associated with breast cancer subtypes with the highest mortality, including triple-negative disease and basal-like molecular phenotype, and that suboptimal levels of vitamin D are associated with an increased risk for recurrence.

"This is one of only a few studies to examine the role of vitamin D in breast cancer progression, rather than cancer development, and the magnitude of the findings were quite surprising," coinvestigator Luke Peppone, PhD, from the University of Rochester Medical Center, said in a press release. "Based on these results, doctors should strongly consider monitoring vitamin D levels among breast cancer patients and correcting them as needed."

Total 25-OH Vitamin D

The study involved 194 newly diagnosed patients with stage 0 to III breast cancer who had total 25-OH vitamin D levels checked 3 months prior to or after their surgery (mean time to assessment, 30 days before surgery). Patients underwent surgery between January 2009 and November 2010. A total of 37,337 patients between the ages of 40 and 70 years who had had their 25-OH vitamin D levels measured at the institute's clinical labs served as the control group. Levels were dichotomized into optimal levels of at least 32 ng/mL and suboptimal levels below 32 ng/mL.

After controlling for relevant covariates, investigators found significant differences between 25-OH vitamin D levels and a number of prognostic variables (Oncotype DX score [a measure of risk for recurrence], tumor stage, estrogen- and progestin-receptor status, HER2 expression, and gene expression).

Significantly Lower Vitamin D Levels

Dr. Skinner noted that breast cancer patients had a significantly lower mean 25-OH vitamin D level than age-matched healthy control subjects, and that the odds of acquiring breast cancer were 2.5-fold greater with deficienct vitamin D levels. "These results may explain the decreased survival rate among vitamin D–deficient breast cancer patients observed by Goodwin et al," she concluded (J Clin Oncol. 2009;27:3757-3763). "We routinely check vitamin D levels and replace them, aiming for a level of about 50."

Commenting on the study, ASBS spokesperson Deanna Attai, MD, from the Center for Breast Care, Inc., in Glendale, California, told Medscape Medical News that whether patients developed more aggressive cancers because they were vitamin D deficient or whether vitamin D deficiency does something in the development of the cancer that changes the tumor from a less aggressive into a more aggressive cancer still isn't known.

"I think we need more research on this, but it is certainly intriguing, and there is no question that vitamin D is something we need to look at in future studies."

Dr. Skinner and Dr. Attai have disclosed no relevant financial relationships.

American Society of Breast Surgeons (ASBS) 12th Annual Meeting: Abstract 1701. Presented April 29, 2011.

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