Vitamin D Linked to Better Breast Cancer Survival

Sufficient vitamin D levels at diagnosis associated with improved outcomes, study finds

Apr. 20, 2026 at 9:08am

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A translucent, ghostly X-ray image of a human breast, with intricate, glowing structures representing the complex relationship between vitamin D, cancer cells, and cardiovascular health.An X-ray view reveals the potential benefits of sufficient vitamin D levels for breast cancer patients' overall health.Buffalo Today

A large prospective study has found that women with breast cancer who had sufficient vitamin D levels at the time of diagnosis had a 24% boost in overall survival compared to those with a vitamin D deficiency. The study also showed a 33% relative reduction in cardiovascular risk factors, such as diabetes and dyslipidemia, among those with sufficient vitamin D.

Why it matters

Vitamin D deficiency is common among women with breast cancer, and prior research has suggested it may worsen patient outcomes. This new study provides further evidence of the potential benefits of maintaining sufficient vitamin D levels around the time of breast cancer diagnosis.

The details

The study, published in the Journal of the National Comprehensive Cancer Network, followed a cohort of nearly 4,000 breast cancer patients for a median of 12.2 years. Researchers found that women with sufficient vitamin D levels (30 ng/mL or higher) at diagnosis had better overall survival, second primary cancer-free survival, and disease-free survival compared to those with vitamin D deficiency (less than 20 ng/mL). The benefits were most pronounced in patients with stage II or higher disease.

  • The study followed patients for a median of 12.2 years.
  • The findings were published online in April 2026.

The players

Alfredo Chua, Jr, MD

Study co-author and researcher at Roswell Park Comprehensive Cancer Center in Buffalo, New York.

Azeez Farooki, MD

Endocrinologist at Memorial Sloan Kettering Cancer Center in New York City, who reviewed the study for Medscape Medical News.

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What they’re saying

“Correction of vitamin D deficiency, even during the time of diagnosis, may represent a simple local strategy to improve both cancer survival outcomes and cardiovascular risk factors in patients with breast cancer.”

— Alfredo Chua, Jr, MD, Study co-author

“What we really need is a randomized clinical trial to prove causality.”

— Azeez Farooki, MD, Endocrinologist

What’s next

Researchers say a randomized clinical trial is needed to further investigate the causal relationship between vitamin D status and breast cancer outcomes.

The takeaway

This study adds to the growing body of evidence suggesting that maintaining sufficient vitamin D levels around the time of breast cancer diagnosis may improve survival and cardiovascular health outcomes for patients. However, more research is still needed to confirm these findings.