Patients receiving a type of vitamin D lived longer after chemotherapy for pancreatic cancer in a small clinical trial run by researchers from the Dana-Farber Cancer Institute in California, United States.
Among 36 patients with previously untreated pancreatic cancer that had metastasised or spread, those taking a type of vitamin D called paricalcitol experienced a significant survival boost one year after the trial, the researchers found.
The supplement, administered orally or by injection, reduced the presence of inflammation and fibroblasts, which are thick mats of connective tissue cells that form the protective shield around many cancers.
“This study really takes a novel approach for cracking therapeutic resistance in pancreatic cancer,” study co-author and Salk Institute for Biological Studies professor of molecular and developmental biology Dr Ronald Evans said in a news release.
“By using vitamin D analogues to engage the body’s own natural system for dampening fibrotic and inflammatory responses, we can enable other therapies to do their job.”
The basis for the clinical trial was foundational research done on vitamin D by Prof Evans’ team at the Salk Institute.
The latest study showed that vitamin supplementation with chemotherapy was not only safe, but also reduced the density of protective tissues surrounding tumours, and increased infiltration of immune T-cells, which are usually blocked from attacking these tumours.
The US Food and Drug Administration-approved synthetic form of vitamin D has been designed to last longer in the body and resist deterioration, they wrote.
Their work was published in the journal Nature Cancer in May (2026).
Pancreatic cancer is difficult to treat as it is rarely caught in its early stages, according to cancercenter.com.
By the time symptoms appear, the tumour has usually spread to surrounding vital organs or metastasised.
In addition, a pancreatic tumour’s dense, fibrous barrier and mutated genes make it harder to treat with standard therapies.
Standard chemotherapy can slow the cancer for some, but outcomes remain poor.
The researchers also found that patients with more receptors for vitamin D had a stronger response to the therapy.
They said that more testing is needed to see how and when to incorporate vitamin D into the therapy. – By Karl Hille/Baltimore Sun/Tribune News Service
