Pregnancy Bliss | Reproductive Health Answers
Published: Tuesday, May 17 2011 - 17:22
By Dr J Kabyemela, MD
Vitamin D has been increasingly found to have many more significant health benefits over and above its well-known role of facilitating calcium metabolism and bone health.
Now, a new study has shown that breast cancer patients with sub-optimal vitamin D levels are more likely to have more aggressive tumours and overall poorer prognosis than those with normal levels of vitamin D.
Kristin Skinner, MD, from the University of Rochester Medical Center in New York, presented the results of a study on April 29, 2011 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. That included ‘triple-negative’ disease and basal-like molecular phenotype. Another significant finding was that vitamin D deficiency was associated with an increased risk for recurrence.
Monitoring Vitamin D in breast cancer patients
"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," co-investigator 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."
The study involved 194 newly diagnosed patients with breast cancer ranging from Stage 0 to III who had total Calcidiol (25-OH vitamin D) levels checked 3 months prior to or after their 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 put in two groups with optimal levels of at least 32 ng/mL and suboptimal levels below 32 ng/mL.
After controlling for relevant co-variates, 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], tumour stage, estrogen- and progestin-receptor status, HER2 expression, and gene expression).
Risk increased over two-fold
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 deficient vitamin D levels. "These results may explain the decreased survival rate among vitamin D–deficient breast cancer patients observed by Goodwin and others (as published in the August 29, 2009 edition of the Journal of Clinical Oncology)," she concluded. "We routinely check vitamin D levels and replace them, aiming for a level of about 50."
Commenting on the study, American Society of Breast Surgeons spokesperson Deanna Attai, MD, from the Center for Breast Care, Inc., in Glendale, California, said “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 tumour from a less aggressive into a more aggressive cancer still isn't known”.