The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 8 No.
2 • April 2005
Vitamin D in Prostate Cancer Patients with Increasing PSA Levels after Treatment
A pilot study examined the effects of vitamin D (cholecalciferol) as a potential treatment for rising PSA levels in the absence of any other signs or symptoms of advancing disease after early treatment for prostate cancer. The need to find ways to treat what is called PSA relapse before the consideration of androgen abatement is important because the latter treatment has a limited period of efficacy, since the cancer cells ultimately become androgen-insensitive and the treatment itself has potentially severe side effects (e.g., impotence and loss of fertility).
The 15 patients in this study had a mean length of time of 65 months from surgery or radiation before they were started on 2000 IU/day of vitamin D. The patients were followed up for a median period of 8 months (4–21 months).
Vitamin D is converted in the body to the hormone calcitriol. Prostate cancer cells slow their rate of replication when exposed to calcitriol. However, the concentrations of calcitriol required for this response are well in excess of the normal physiological levels of the hormone, while physiological concentrations of 25-hydroxycholecalciferol, a metabolite of vitamin D, can also produce this effect. Past studies are reported to have shown that 2000 IU/day of vitamin D improved bone-pain scores and muscle strength in patients with metastatic prostate cancer.
Of the 15 patients, eight had a decrease in absolute serum PSA level that lasted for 5–17 months after starting vitamin D treatment, while another patient had a PSA value that fluctuated around the baseline value, with no clear trend for increase or decrease. In the absence of vitamin D supplementation, there was no significant change in the rate of rise of PSA. In the vitamin D-treated patients, the PSA doubling time increased (that is, it took significantly longer for PSA levels to increase to twice their initial value) in 14 out of 15 patients.
The authors note that, even without any treatment, prostate cancer patients may remain symptom-free for a long time. From the onset of PSA relapse in the absence of treatment, it took a median of about 7.5 years for postsurgical patients to develop distant metastases, and then a further median 6.5 years to death. The authors suggest that, in the face of such a long development time, a cheap and relatively safe substance such as vitamin D could be very useful, assuming that larger studies replicate these findings of a reduced rise in PSA.
As vitamin D is cheap, beneficial, and has few potential side effects at 2000 IU/day, we already take that much. In fact, earlier studies had already shown vitamin D to be protective against cancer, type 1 diabetes, heart disease, and osteoporosis. Another study found that 1,25-dihydroxyvitamin D3 (D3), an active metabolite of vitamin D, is neuroprotective, inducing neurotrophic factors such as GDNF (glial-derived neurotrophic factor), NGF (nerve-growth factor), and NT3/NT4 (neurotrophin 3/4) in vivo and in vitro in rodents. The authors of the latter paper, in fact, suggest that “… this vitamin [D3] may be potentially useful in treatment of Parkinson’s disease and other neurodegenerative disorders.”
- Woo et al. Pilot study: potential role of vitamin D (cholecalciferol) in patients with PSA relapse after definitive therapy. Nutr Cancer 51(1):32-6 (2005).
- See, e.g., Holick. Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis. Am J Clin Nutr 79:362-71 (2004).
- Wang et al. Vitamin D3 attenuates 6-hydroxydopamine-inducing neurotoxicity in rats. Brain Res 904:67-75 (2001).