There is a significant relation between lifestyle (including food consumption) and cancer prevention.
Two medications which block the conversion of testosterone to dihydrotestosterone, finasteride and dutasteride, have also shown some promise. The use of these medications for primary prevention is still in the testing phase, and they are not widely used for this purpose. A 2008 study found that finasteride reduces the incidence of prostate cancer by 30%, without any increase in the risk of High-Grade prostate cancer. In the original study it turns out that the smaller prostate caused by finasteride means that a doctor is more likely to hit upon cancer nests and more likely to find aggressive-looking cells.
Taking 5-alpha-reductase inhibitors (5-ARIs) can reduce a man’s risk of being diagnosed with prostate cancer from around 5–9% to around 4-6% during up to 7 years of treatment.
Ejaculation frequency
More frequent ejaculation also may decrease a man's risk of prostate cancer. One study showed that men who ejaculated 3-5 times a week at the age of 15-19 had a decreased rate of prostate cancer when they are old, though other studies have shown no benefit. The results contradict those of previous studies, that suggested that having many sexual partners, or a high frequency of sexual activity, increases the risk of prostate cancer by up to 40 percent. A key difference may be that these earlier studies defined sexual activity as sexual intercourse, whereas this study focused on the number of ejaculations, whether or not intercourse was involved. An explanation for this discrepancy may be that sex with partners increases the risk of contracting sexually transmitted diseases, including cryptic infections, which increase the risk of cancers. Another study completed in 2004 reported that "Most categories of ejaculation frequency were unrelated to risk of prostate cancer. However, high ejaculation frequency was related to decreased risk of total prostate cancer." The report abstract concluded, "Our results suggest that ejaculation frequency is not related to increased risk of prostate cancer."
Diet
It is recommended that people maintain a normal weight (limiting consumption of energy dense foods and sugary drinks), eat plant based food, limit red and processed meat, and limit alcohol. Some evidence supports a vegetarian or vegan diet. Consuming fish appears to lower prostate cancer deaths but not the occurrence of prostate cancer. Omega-3 fatty acids are unlikely to prevent prostate cancer. There is no evidence that vitamin supplements affect risk. Trans fats may be associated with an increased risk of cancer but the evidence is still limited.
