Status of selenium in prostate cancer prevention

Area of Science:

• Nutritional Epidemiology
• Cancer Prevention Research
• Mineral Metabolism

Background:

• The Nutritional Prevention of Cancer Trial investigated the long-term effects of selenium (Se) supplementation.
• Previous findings suggested a reduction in cancer risk with Se supplementation, prompting further analysis.
• Understanding the role of selenium in cancer prevention requires evaluating its transport, uptake, and chemical forms.

Purpose of the Study:

• To analyze the complete 13-year results of the Nutritional Prevention of Cancer Trial.
• To confirm and assess the robustness of previously reported reductions in cancer risk associated with selenium supplementation.
• To explore the mechanisms underlying selenium's effects on cancer development and progression.

Main Methods:

• Analysis of 13-year data from the Nutritional Prevention of Cancer Trial cohort.
• Subgroup analyses based on baseline plasma selenium levels.
• Review of recent findings on selenium's effects on prostate cancer cell apoptosis and proliferation.

Main Results:

• Selenium supplementation was associated with significant reductions in total (non-skin) carcinomas, prostate cancer, and colon-rectum cancer.
• The most robust effect was observed for prostate cancer, supported by prostate-specific antigen (PSA) level data.
• Cancer risk reduction was most prominent in participants with plasma Se levels in the lowest tertile at trial entry.

Conclusions:

• Selenium supplementation demonstrates a significant protective effect against certain cancers, notably prostate and colorectal cancers.
• The efficacy of selenium supplementation is influenced by baseline selenium status, suggesting a threshold effect.
• Further research into selenium's biological mechanisms, transport, and dietary forms is crucial for optimizing its cancer-preventive potential and ensuring safety and sustainability.