In a study published in the journal "Cancer Research", scientists from Stanford University discovered that the amount of both -- activated vitamin D, or calcitriol, and the NSAIDs -- could be reduced by half to one-tenth the dosage to thwart prostate cancer cell growth in cell lines and primary tissue cultures.
If work in animal models and human trials confirm the findings, the drug combination may help to keep the NSAID family of drugs among the pharmaceutical choices for the prevention and treatment of cancer. This list includes ibuprofen, indomethacin and naproxen, in addition to other so-called COX-2 inhibitors linked to increased risk for cardiovascular disease, including Vioxx and Celebrex.
"NSAIDs have their own risks," said David Feldman, M.D., professor of Medicine in the Division of Endocrinology, Gerontology and Metabolism at the Stanford University School of Medicine. "So, we have to be careful even with lower doses and we still need to watch the patients very closely if we intend to keep them on these drugs for extended periods of time. But we are aiming to find doses that are less toxic and far more tolerable for the patient."
As outlined in their study, the Stanford scientists discovered that vitamin D, known as the "sunshine vitamin," works to limit the growth of prostate cancer cells by interfering with the same molecules attacked by NSAIDs -- the prostaglandin/COX-2 pathway.
Prostaglandins are responsible for activating the inflammatory response that results in pain and fever. NSAIDs work by blocking an enzyme called cyclooxygenase-2 or COX-2 which is essential for prostaglandin synthesis, thereby relieving some of the effects of pain and fever.