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Vitamin Supplementation and Prostate Cancer

Monday, July 11, 2011 // Uncategorized

There has been a lot of interest over the years with vitamin and mineral supplementation and prostate cancer.  I took vitamin E and selenium until a study was published showing that there was no benefit.

Selenium, Vitamin E, and Prostate Cancer

Selenium and vitamin E, alone or combined, did not affect risk for prostate cancer in a healthy population.

Chemoprevention of major epithelial cancers — a major focus of clinical research during the past 10 to 15 years — has achieved some measure of success, notably regarding the activity of tamoxifen in breast cancer (JW Oncol Hematol Mar 12 2007 and J Natl Cancer Inst 1998; 90:1371). Such advances in prostate cancer have been less forthcoming, although researchers have reported hypothesis-generating data regarding the potential for selenium (S) and vitamin E (E) to lower prostate cancer incidence and overall disease-related mortality (J Natl Cancer Inst 1998; 90:1219). These data, along with epidemiologic and preclinical data, led an international group of investigators to conduct the phase III placebo-controlled Selenium and Vitamin E Cancer Prevention Trial (SELECT).

A total of 35,533 eligible participants was composed of black men aged ≥50 and men of other races aged ≥55, all of whom had prostate-specific antigen (PSA) levels ≤4, unremarkable digital rectal exams (DREs), and no prior prostate cancer diagnoses. Participants were randomized to receive E (400 IU daily), S (200 µg daily), E plus S, or placebo. All four groups were screened and followed up based on community standards at 6-month intervals; PSA and DRE tests were not mandated, given the lack of evidence of screening benefit at study initiation.

At median follow-up of 5.46 years (range, 7–12 years), no significant differences were found between groups in terms of prostate cancer incidence (the primary endpoint) as determined by routine clinical assessment. Early-stage and low-grade prostate cancers were the most common cancer types diagnosed during the trial; incidence of these types was similar for all groups. Nonsignificantly elevated risks were noted for prostate cancer in the E group and for type 2 diabetes in the S group.

Comment: These results, as well as those of a recent randomized trial of vitamins C and E (J Natl Cancer Inst 2006; 98:245), point out the limitations of chemoprevention in prostate cancer as well as the need for well-designed, adequately powered randomized trials. Patients routinely use a variety of supplements and alternative agents to try to augment the therapeutic value of prescribed treatments; others use supplements in cancer-prevention strategies. Although the current findings are disappointing, they show that patients can be readily enrolled in large prevention studies (which often is not the case for therapeutic oncology studies), setting the stage for the next series of appropriately designed trials.

Robert Dreicer, MD, MS, FACP

Published in Journal Watch Oncology and Hematology February 3, 2009

Citation(s):

Lippman SM et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: The Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2009 Jan 7; 301:39.

  This is the latest article which shows that there are no benefits to vitamin supplementation. 

Stratton J, Godwin M. The effect of supplemental vitamins and minerals on the development of prostate cancer: a systematic review and meta-analysis. Fam Pract. 2011 Jun;28(3):243-52. Epub 2011 Jan 27. (Review) PMID: 21273283

BACKGROUND: Vitamin supplementation is used for many purposes with mainly alleged benefits. One of these is the use of various vitamins for the prevention of prostate cancer.
METHODS: We conducted a systematic review and meta-analysis on this topic. Pubmed, Embase and the Cochrane Database were searched; as well, we hand searched the references in key articles. Randomized controlled trials (RCTs), cohort studies and case-control studies were included. The review assessed the effect of supplemental vitamins on the risk of prostate cancer and on disease severity and death in men with prostate cancer.
RESULTS: Fourteen articles were included in the final assessment. Individually, a few of these studies showed a relationship between the ingestion of supplemental vitamins or minerals and the incidence or severity of prostate cancer, especially in smokers. However, neither the use of multivitamin supplementation nor the use of individual vitamin/mineral supplementation affected the overall occurrence of prostate cancer or the occurrence of advanced/metastatic prostate cancer or death from prostate cancer when the results of the studies were combined in a meta-analysis. We also conducted several sensitivity analyses by running meta-analysis using just the higher quality studies and just the RCTs. There were still no associations found.
CONCLUSIONS: There is no convincing evidence that the use of supplemental multivitamins or any specific vitamin affects the occurrence or severity of prostate cancer. There was high heterogeneity among the studies so it is possible that unidentified subgroups may benefit or be harmed by the use of vitamins.

Bottom line:  Another study shows that vitamins and supplements are of no benefit.  Health doesn’t come in a pill.

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