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Prostate cancer reduced in high vitamin D two studies – April 2012

Oral Vitamin D Supplements Reduced Levels of Ki67 in Prostate Cancer Cells

PressRelease March 31, 2012

Ki67 is a protein that indicates cancer cell growth.
Vitamin D increased prostate tissue calcitriol levels, which lowered Ki67.

CHICAGO — Higher oral doses of plain vitamin D raised levels of calcitriol in prostate tissue. Higher prostate levels of calcitriol, a hormone made from vitamin D, corresponded with lower levels of the proliferation marker Ki67 and increased levels of cancer growth-inhibitory microRNAs in prostate cancer cells, according to data presented at the AACR Annual Meeting 2012, held here March 31 - April 4.

The results not only point to the mechanisms by which vitamin D affects the rate of prostate cancer growth, but also indicate that vitamin D may slow the growth of prostate cancer cells — a key finding given that the role of vitamin D in prostate cancer has been “controversial, with some suggesting that higher levels of vitamin D should be avoided,” said Reinhold Vieth, Ph.D., professor at the University of Toronto in Toronto, Ontario, Canada.

“This study shows calcitriol makes the foot come off the gas pedal of cancer growth. We are not able to prove that the speed of the car has slowed down, but it certainly is a good sign,” said Vieth. “We expect that this early-phase clinical trial will open the door for more detailed clinical research into the usefulness of vitamin D in the treatment or prevention of prostate cancer.”

Vieth and colleagues previously reported that in men who were being monitored regularly for prostate cancer, higher vitamin D levels slowed the rate of rise in prostate-specific antigen levels.
They randomly assigned 66 men scheduled for radical prostatectomy to daily vitamin D in doses of

  • 400,
  • 10,000 or
  • 40,000 IU for three to eight weeks before surgery.

Researchers found that calcitriol levels in the prostate increased progressively with each daily dose of vitamin D, with 40,000 IU showing the highest levels. These higher levels of calcitriol corresponded with lower prostate levels of Ki67, a protein that indicates prostate cancer cell growth, as well as higher levels of specific growth-inhibitory microRNAs.

Vieth stressed that he and his colleagues do not advocate vitamin D supplementation in doses higher than 4,000 IU daily. Patients were assigned to the 40,000 IU daily dose because of the short presurgical time frame available for study, not as a regular regimen.

“Plain vitamin D provides the raw material to permit the body to take care of its own needs,” he said. “We showed here that plain vitamin D allows the prostate to regulate its own level of calcitriol, and at the doses we used, for the time frame we used, it has been safe with the hoped-for desirable outcomes.”

The next step in this line of research will be to conduct a phase III clinical trial in which men who are being monitored for prostate cancer progression will be randomly assigned to placebo or to a “high” dose of plain vitamin D.

This research was funded by the Canadian Cancer Society and was a collaboration between investigators at University Health Network, Sunnybrook Hospital and Mount Sinai Hospital, all in Toronto, and at the University of Chicago.
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Vitamin D3 Supplementation at 4000 International Units Per Day for One Year

Results in a Decrease of Positive Cores at Repeat Biopsy in Subjects with Low-Risk Prostate Cancer under Active Surveillance.
The Journal of Clinical Endocrinology & Metabolism April 16, 2012 jc.2012-1451
Marshall DT, Savage SJ, Garrett-Mayer E, Keane TE, Hollis BW, Horst RL, Ambrose LH, Kindy MS, Gattoni-Celli S gattonis at musc.edu .
Departments of Radiation Oncology (D.T.M., L.H.A., S.G.-C.), Urology (S.J.S., T.E.K.), Medicine (Biostatistics) (E.G.-M.), Pediatrics (B.W.H.), and Neurosciences (M.S.K.), Medical University of South Carolina, Charleston, South Carolina 29425; Ralph H. Johnson Veterans Affairs Medical Center (S.J.S., M.S.K., S.G.-C.), Charleston, South Carolina 29401; and Department of Animal Science (R.L.H.), Iowa State University, Ames, Iowa 50011.

Context: We wanted to investigate vitamin D in low-risk prostate cancer.Objectives:The objective of the study was to determine whether vitamin D(3) supplementation at 4000 IU/d for 1 yr is safe and would result in a decrease in serum levels of prostate-specific antigen (PSA) or in the rate of progression.

Design: In this open-label clinical trial (Investigational New Drug 77,839), subjects were followed up until repeat biopsy.

Setting:All subjects were enrolled through the Medical University of South Carolina and the Ralph H. Johnson Veterans Affairs Medical Center, both in Charleston, SC.

Patients and Other Participants: All subjects had a diagnosis of low-risk prostate cancer.
Fifty-two subjects were enrolled in the study, 48 completed 1 yr of supplementation, and 44 could be analyzed for both safety and efficacy objectives.

Intervention:The intervention included vitamin D(3) soft gels (4000 IU).

Main Outcome Measures: Adverse events were monitored throughout the study. PSA serum levels were measured at entry and every 2 months for 1 yr. Biopsy procedures were performed before enrollment (for eligibility) and after 1 yr of supplementation.Results:No adverse events associated with vitamin D(3) supplementation were observed. No significant changes in PSA levels were observed. However, 24 of 44 subjects (55%) showed a decrease in the number of positive cores or decrease in Gleason score; five subjects (11%) showed no change; 15 subjects (34%) showed an increase in the number of positive cores or Gleason score.

Conclusion:Patients with low-risk prostate cancer under active surveillance may benefit from vitamin D(3) supplementation at 4000 IU/d.

PMID: 22508710

Gleason Score:

All patients started with score = 6 (Range from 2 to 10, with 10 = worst)
Score based upon its microscopic appearance.

Mean vitamin D levels:

  • 32 ng/ml before (seems high. Most prostate cancer vitamin D levels are much lower)
    Wonder if “Low Risk” Prostate Cancer is associated with higher levels of vitamin D
  • 66 ng/ml after
  • Does not indicate difference in the responders vs non-responders (increased Gleason Score)

Vitamin D Council description of the study behind a $5 paywall

Study lacks

See also VitaminDWiki

See also US Clinical Trials

See also web