Vitamin E, selenium, + soy to treat prostate cancer?
High-grade prostatic intraepithelial neoplasia (HGPIN) is a precursor of invasive prostate cancer (PCa). Some preliminary evidence suggests vitamin E, selenium, and soy protein may prevent progression of HGPIN to PCa.
Researchers at Princess Margaret Hospital, in Toronto, Ontario tested this hypothesis.
First, the details.
- 303 men with biopsy-confirmed HGPIN were randomly assigned to a treatment group for 3 years.
- Daily soy (40 g), vitamin E (800 U), + selenium (200 ?g)
- Placebo
- Follow-up prostate biopsies occurred at 6, 12, 24, and 36 months.
- The time to development of invasive PCa was recorded.
- Neither the patients nor researchers knew the treatment given — double blind.
And, the results.
- Invasive PCa developed in 26% of patients.
- The nutritional supplement did not prevent PCa.
- Gleason score distribution was similar in both groups.
- Gleason score is a grading system to help evaluate the prognosis of men with prostate cancer.
- Baseline age, weight, prostate-specific antigen (PSA; a protein produced by the cells of the prostate gland), and testosterone did not predict for development of PCa.
- The supplement was well tolerated with flatulence reported more frequently (27% v 17%) among men receiving micronutrients.
The bottom line?
The authors concluded, “This trial does not support the hypothesis that combination vitamin E, selenium, and soy prevents progression from HGPIN to PCa.”
Interesting, although an earlier study came to a different conclusion.
Researchers at the University Hospitals Katholieke Universiteit Leuven, in Belgium, concluded that a 6-month supplementation challenge with selenium, vitamin E, and soy isoflavonoids in men with biopsy-diagnosed isolated HGPIN “predicts for a significantly lower risk of PCa in future biopsies.”
5/6/11 22:20 JR