Randomized clinical trial of brewed green and black tea in men with prostate cancer prior to prostatectomy

Abstract

Background Preclinical and epidemiologic studies suggest chemopreventive effects of green tea (GT) and black tea (BT) in prostate cancer. In the current study we determined the effect of GT and BT consumption on biomarkers related to prostate cancer development and progression. Methods In this exploratory, open label, phase II trial 113 men diagnosed with prostate cancer were randomized to consume six cups daily of brewed GT, BT or water (control) prior to radical prostatectomy (RP). The primary endpoint was prostate tumor markers of cancer development and progression determined by tissue immunostaining of proliferation (Ki67), apoptosis (Bcl-2, Bax, Tunel), inflammation [nuclear and cytoplasmic nuclear factor kappa B (NFκB)] and oxidation [8-hydroxydeoxy- guanosine (8OHdG)]. Secondary endpoints of urinary oxidation, tea polyphenol uptake in prostate tissue, and serum prostate specific antigen (PSA) were evaluated by high performance liquid chromatography and ELISA analysis. Results Ninety three patients completed the intervention. There was no significant difference in markers of proliferation, apoptosis and oxidation in RP tissue comparing GT and BT to water control. Nuclear staining of NFkB was significantly decreased in RP tissue of men consuming GT (p=0.013) but not BT (p=0.931) compared to water control. Tea polyphenols were detected in prostate tissue from 32 of 34 men consuming GT but not in the other groups. Evidence of a systemic antioxidant effect was observed (reduced urinary 8OHdG) only with GT consumption (p=0.03). GT, but not BT or water, also led to a small but statistically significant decrease in serum prostate-specific antigen (PSA) levels (p=0.04). Conclusion Given the GT-induced changes in NFkB and systemic oxidation, and uptake of GT polyphenols in prostate tissue, future longer-term studies are warranted to further examine the role of GT for prostate cancer prevention and treatment, and possibly for other prostate conditions such as prostatitis.

Cucurbitacin E induces apoptosis of human prostate cancer cells via cofilin-1 and mTORC1

“…Although castration is effective in patients with early stage PC, other therapeutic regimes are limited by the development of hormonal-refractory or hormone-resistant PC (20). The present study demonstrated that cucurbitacin E exerted cytotoxic effects on LNCaP cells, decreasing the cell viability and inducing apoptosis.…”

Effect of green tea catechins in patients with high-grade prostatic intraepithelial neoplasia: Results of a short-term double-blind placebo controlled phase II clinical trial

“…Therefore, we speculate that the significant reduction of PSA values throughout the one-year study, as well as the not significant decrease of PCa at the 6 month follow up, we observed in our study, could be linked to the anti-inflammatory property of green tea. This hypothesis was also supported by a recent open label, phase II clinical trial carried out in 113 men diagnosed with prostate cancer randomized who received six cups daily of brewed green tea or brown tea or water for three to eight weeks prior to radical prostatectomy (31). In prostate tissue, Henning et al found that green tea consumption led to a significant decrease in nuclear immunostaining of nuclear factor kappa B (NFκB) compared to water control, which may reduce inflammatory processes that may contribute to prostate cancerogenesis.…”

Green Tea and Its Extracts in Cancer Prevention and Treatment

“…In a US study, freshly brewed GT decreased NFkB in tumor tissue and serum PSA; black tea had no effect on these parameters, apoptosis was not influenced by either tea [Henning 2015]. Taken together, these clinical studies indicate that GTE likely lacks any effect on prostate cancer growth or recurrence.…”