Open Access

Prasan Ratha

• Low risk prostate cancer does not always necessitate aggressive or invasive intervention and is best monitored through active surveillance, but in daily practice a majority of men seek a more proactive approach. Therefore, tertiary chemoprevention is an attractive option for men seeking a way to slow disease progression. Several natural anti-carcinogens have been identified in soy beans, especially isoflavones. Case series have been published, demonstrating a positive influence of isoflavones on PSA serum levels in prostate cancer. Therefore, a systematic review of the effect of isoflavones versus placebo on PSA levels in localized prostate cancer was conducted, following the recommendations of the Cochrane Handbook of systematic Reviews. On the whole, the primary aim of this review is to summarize the evidence for the use of isoflavones in localized prostate cancer in terms of PSA response. In total, we identified four relevant RCTs involving 298 treated men. The result of this synopsis was that none of the studies showed a significant effect on serum PSA levels, suggesting that isoflavone intake has no effect on biochemical progression. The influence of isoflavones on overall survival in localized prostate cancer remains unclear. Nevertheless, there are indications that isoflavones may be clinically beneficial, for example regarding lipid metabolism and cholesterol. Isoflavones represent a safe therapeutic option with few side effects, where further interdisciplinary research is needed.