The effects of soy isoflavone and curcumin on the serum PSA level of the biopsy-negative men

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Background: Chronic inflammation in the prostate can be a cause of high serum PSA level, which may also contributeto prostate carcinogenesis. Isoflavones have several effects including anti-inflammatory effects and inhibition of tyrosine kinasesand topoisomerases. Several animal studies have suggestedthat isoflavones have the ability to slow the growthof prostate tumors and prevent their occurrence. Curcumin exertedstrong antioxidant and anti-inflammatory activities by suppressingboth constitutive and inducible nuclear factor- κB andactivator protein-1 activation. Curcumin has been shown to inhibit growth and induce apoptosis in cultured prostate cancer cells. We examined the the effects of soy isoflavone and curcumin on the serum PSA level in the biopsy-negative men. Materials and Methods: We conducted a randomized, double-blinded, placebo-controlled study testing the effects of soy isoflavonesand curcumin on serum PSA among men enrolled in an interventiontrial. Under the approval of local IRB, 89 participants were recruited from men who underwent systemic prostate biopsy because of the elevated level of PSA and were not found either cancer or PIN. They daily took either 2 tablets including isoflavones and curcumin or placebo for 6 months. We compared change inPSA concentration, IPSS, and QOL over the intervention between isoflavone+curcumin (I+S)and placebo (P) groups at the time of enrollment and 6-months later. The change of serum PSA value between the baseline and 6-months later (ΔPSA) was compared among groups. Results: Participants were subgrouped by the cut off PSA level of 10 ng/ml. PSA level at 6-months was significantly decreased in the group of I+S, PSA≥10.(P: PSA<10 (ΔPSA), -0.451, ≥10, -2.620, S: PSA <10,-0.201, ≥10:-9.069, p<0.001) Conclusion: Given the increasing public awareness of prostate cancer, the use of complementary therapies has been increasing among prostate cancer patients and men perceived at high risk for the disease. Previous studies showed that isoflavones does not modulate the level of serum PSA. Our results may indicate that soy isoflavone and curcumin can modulate serum PSA level presumably through the inhibition of inflammation..