A Summary of Proposed Agents for the Prevention of Prostate Cancer, Mechanisms, Demonstrated Benefits, Potential Harm and Quality of Evidence
| Agents | Proposed Mechanism* | Demonstrated Benefit | Potential Harm | Quality of Evidence† |
|---|---|---|---|---|
| Finasteride | Inhibits 5-alpha reductase, lowers DHT | Decreased incidence/diagnosis of prostate cancer, improved urinary symptoms | Increased sexual side effects, may increase risk of high-grade prostate cancer | Level 1 |
| Dutasteride | Inhibits 5-alpha reductase, lowers DHT | Decreased incidence/diagnosis of prostate cancer, improved urinary symptoms | Increased sexual side effects, may increase risk of high-grade prostate cancer | Level 1 |
| Selenium | Inhibits clonal expansion of prostate cancer cells | No effect | May increase type II diabetes mellitus | Level 1 |
| Vitamin E | Cell membrane antioxidant | No effect | May increase prostate cancer incidence, all cause mortality, and hemorrhagic stroke | Level 1 |
| Vitamin C | Antioxidant | No effect | No effect | Level 2 |
| Beta-carotene | Antioxidant | No effect | Increased risk of lung and gastric cancers | Level 2 |
| Multivitamins | Various mechanisms | No effect | May increase rate of prostate specific death | Level 2 |
| Lycopene | Antioxidant | Possible effect but conflicting evidence | Unknown | Level 2 |
| NSAIDs | Reduces prostaglandin 2 and arachidonic acid | Unclear effect on prostate cancer incidence | Increased risk GI bleed | Level 3 |
| Aspirin | Inhibit cell migration | May decrease risk of prostate cancer | Increased risk GI bleed | Level 3 |
| Cox 2 inhibitors | Pro-apoptotic agent | No effect | Risk of cardiovascular events at high dose | Level 3 |
| Statins | Multiple potential cholesterol and non-cholesterol-dependent mechanisms | May lower incidence of advanced prostate cancer | Myalgia, hepatic dysfunction | Level 3 |
| Toremifene | Selective estrogen receptor modulator | May decrease incidence of prostate cancer | Hot flashes, nausea, hepatic dysfunction | Level 3 |
| Soy | Weak estrogen | Increased intake may decrease prostate caner risk | Unknown | Level 3 |
| Protein/meat intake | Unknown; may be related to fat intake | Lowering meat intake has not been shown lower cancer risk | Increased red meat intake may have increased risk of prostate cancer | Level 3 |
| Fat intake | Fat increases circulating androgen | Conflicting evidence for lowering fat intake on prostate cancer, but documented benefit to cardiovascular health | High-fat diets are associated with higher incidence and more advanced prostate cancer | Level 3 |
| Fish consumption | Via modifying omega 3:omega 6 fatty acid ratio | Increased fish intake may decrease prostate cancer death | Unknown | Level 3 |
↵* There are no clearly identified causal mechanisms for prostate cancer prevention; commonly accepted mechanisms with some evidence from preclinical investigations are presented.
↵† Levels of evidence employ the strength of recommendation taxonomy (SORT) as described in Ebell MH, Siwek J, Weiss BD, et al. Strength of recommendation taxonomy (SORT): a patient-centered approach to grading evidence in the medical literature. J Am Board Fam Pract 2004;17:59–67.
DHT, dihydrotestosterone; GI, gastrointestinal; NSAIDs, nonsteroidal anti-inflammatory drugs.