***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Prostate cancer incidence was prospect ively studied among 7999 men of Japanese ancestry who were first examined between 1965 and 1968 and then followed through 1986 . During this surveillance period , 174 incident cases of prostate cancer were recorded . Prostate cancer was not associated with any measure of socioeconomic status , including amount of education , type of occupation , and type of residence . There was also no relationship with the number of children , as a surrogate measure of sexual activity . Increased consumption of rice and tofu were both associated with a decreased risk of prostate cancer , while consumption of seaweeds was associated with an increased risk of prostate cancer . There was no relationship between prostate cancer and the intake of various nutrients , including total fat and total protein . Etiological implication s of these associations are discussed , but more research is needed on these dietary factors and the subsequent development of prostate cancer before any firm conclusions can be drawn Green and black tea have shown promise in the chemoprevention of prostate cancer . The objective of this study was to determine the bioavailability and bioactivity of tea polyphenols ( PP ) and theaflavins in human serum and human and mouse tissues . A decaffeinated black tea diet was administered to C57BL/6 mice . PPs and theaflavins were found in the small and large intestine , liver , and prostate in conjugated and free forms . The relative prostate bioavailability of theaflavin was 70 % higher than that of epigallocatechin gallate ( EGCG ) . In the second mouse study , a green tea ( GT ) diet was administered followed by the control diet for 1 - 5 d. Epicatechin ( EC ) , EGCG , and epicatechin gallate ( ECG ) concentrations in prostate tissue were significantly decreased after 1 d of consuming the control diet . Epigallocatechin gallate ( EGC ) , however , did not decrease significantly . For the human study , 20 men scheduled for surgical prostatectomy were r and omly assigned to consume 1.42 L daily of GT , BT , or a caffeine-matched soda control ( SC ) for 5 d before radical prostatectomy . Tea PPs were greater in prostate sample s from men consuming BT and GT than in men consuming SC ( P = 0.0025 ) . Although tea PP were not detectable in serum , ex vivo LNCaP prostate cancer cell proliferation was less when cells were grown in media containing patient serum collected after BT ( P < 0.001 ) and GT ( P = 0.025 ) consumption relative to baseline serum This is the first human study to show that tea polyphenols and theaflavins are bioavailable in the prostate where they may be active in the prevention of prostate cancer The purpose of this study was to determine the effects of short-term supplementation with the active compounds in green tea on serum biomarkers in patients with prostate cancer . Twenty-six men with positive prostate biopsies and scheduled for radical prostatectomy were given daily doses of Polyphenon E , which contained 800 mg of (−)-epigallocatechin-3-gallate ( EGCG ) and lesser amounts of (−)-epicatechin , (−)-epigallocatechin , and (−)-epicatechin-3-gallate ( a total of 1.3 g of tea polyphenols ) , until time of radical prostatectomy . Serum was collected before initiation of the drug study and on the day of prostatectomy . Serum biomarkers hepatocyte growth factor ( HGF ) , vascular endothelial growth factor ( VEGF ) , insulin-like growth factor (IGF)-I , IGF binding protein-3 ( IGFBP-3 ) , and prostate-specific antigen ( PSA ) were analyzed by ELISA . Toxicity was monitored primarily through liver function enzymes . Changes in serum components were analyzed statistically using the Wilcoxon signed rank test . Cancer-associated fibroblasts were treated with EGCG , and HGF and VEGF protein and mRNA levels were measured . HGF , VEGF , PSA , IGF-I , IGFBP-3 , and the IGF-I/IGFBP-3 ratio decreased significantly during the study . All of the liver function tests also decreased , five of them significantly : total protein , albumin , aspartate aminotransferase , alkaline phosphatase , and amylase . The decrease in HGF and VEGF was confirmed in prostate cancer – associated fibroblasts in vitro . Our results show a significant reduction in serum levels of PSA , HGF , and VEGF in men with prostate cancer after brief treatment with EGCG ( Polyphenon E ) , with no elevation of liver enzymes . These findings support a potential role for Polyphenon E in the treatment or prevention of prostate cancer Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more The incidence of prostate cancer is much lower in Asian than Western population s. Given that environmental factors such as dietary habits may play a major role in the causation of prostate cancer and the high consumption of green tea in Asian population s , this low incidence may be partly due to the effects of green tea . The JPHC Study ( Japan Public Health Center-based Prospect i ve Study ) was established in 1990 for cohort I and in 1993 for cohort II . The subjects were 49,920 men aged 40 - 69 years who completed a question naire that included their green tea consumption habit at baseline and were followed until the end of 2004 . During this time , 404 men were newly diagnosed with prostate cancer , of whom 114 had advanced cases , 271 were localized , and 19 were of an undetermined stage .  Green tea was not associated with localized prostate cancer . However , consumption was associated with a dose-dependent decrease in the risk of advanced prostate cancer . The multivariate relative risk was 0.52 ( 95 % confidence interval : 0.28 , 0.96 ) for men drinking 5 or more cups/day compared with less than 1 cup/day ( p(trend ) = 0.01 ) . Green tea may be associated with a decreased risk of advanced prostate cancer Pre clinical , epidemiologic , and prior clinical trial data suggest that green tea catechins ( GTC ) may reduce prostate cancer risk . We conducted a placebo-controlled , r and omized clinical trial of Polyphenon E ( PolyE ) , a proprietary mixture of GTCs , containing 400 mg (−)-epigallocatechin-3-gallate ( EGCG ) per day , in 97 men with high- grade prostatic intraepithelial neoplasia ( HGPIN ) and /or atypical small acinar proliferation ( ASAP ) . The primary study endpoint was a comparison of the cumulative one-year prostate cancer rates on the two study arms . No differences in the number of prostate cancer cases were observed : 5 of 49 ( PolyE ) versus 9 of 48 ( placebo ) , P = 0.25 . A secondary endpoint comparing the cumulative rate of prostate cancer plus ASAP among men with HGPIN without ASAP at baseline , revealed a decrease in this composite endpoint : 3 of 26 ( PolyE ) versus 10 of 25 ( placebo ) , P < 0.024 . This finding was driven by a decrease in ASAP diagnoses on the Poly E ( 0/26 ) compared with the placebo arm ( 5/25 ) . A decrease in serum prostate-specific antigen ( PSA ) was observed on the PolyE arm [ −0.87 ng/mL ; 95 % confidence intervals ( CI ) , −1.66 to −0.09 ] . Adverse events related to the study agent did not significantly differ between the two study groups . Daily intake of a st and ardized , decaffeinated catechin mixture containing 400 mg EGCG per day for 1 year accumulated in plasma and was well tolerated but did not reduce the likelihood of prostate cancer in men with baseline HGPIN or ASAP . Cancer Prev Res ; 8(10 ) ; 879–87 . © 2015 AACR Purpose Tea is one of the most commonly consumed beverages worldwide . To date , observational data from prospect i ve cohort studies investigating the relationship between green and black tea intake and prostate cancer risk are sparse and equivocal . In a population -based , prospect i ve cohort study of Chinese men in Singapore , we investigated the relationship between green and black tea intake and prostate cancer risk . Methods  Tea consumption data for 27,293 men were collected at baseline ( between 1993 and 1998 ) using a vali date d food frequency question naire . After an average of 11.2 years of follow-up , 298 men had developed prostate cancer . Proportional hazards regression methods were used to assess the associations between tea intake and prostate cancer risk . Results There was no association between daily green tea intake and prostate cancer risk , compared with no green tea intake [ hazard ratio ( HR ) = 1.08 ; 95 % confidence interval ( CI ) 0.79 , 1.47 ] . For black tea , a statistically significant positive association and trend were observed for daily intake compared with no black tea intake ( HR = 1.41 , 95 % CI 1.03 , 1.92 ; p for trend < 0.01 ) Conclusions Few prospect i ve data are available from population s that have both a high level and wide range of black and green tea intake ; this study represents a unique opportunity to evaluate their individual effects on prostate cancer risk . Our findings support the notion that green tea intake does not protect against prostate cancer and that black tea intake may increase prostate cancer risk Compelling pre clinical and pilot clinical data support the role of green tea polyphenols in prostate cancer prevention . We conducted a r and omized , double-blind , placebo-controlled trial of polyphenon E ( enriched green tea polyphenol extract ) in men with prostate cancer scheduled to undergo radical prostatectomy . The study aim ed to determine the bioavailability of green tea polyphenols in prostate tissue and to measure its effects on systemic and tissue biomarkers of prostate cancer carcinogenesis . Participants received either polyphenon E  ( containing 800 mg epigallocatechin gallate ) or placebo daily for 3 to 6 weeks before surgery . Following the intervention , green tea polyphenol levels in the prostatectomy tissue were low to undetectable . Polyphenon E intervention result ed in favorable but not statistically significant changes in serum prostate-specific antigen , serum insulin-like growth factor axis , and oxidative DNA damage in blood leukocytes . Tissue biomarkers of cell proliferation , apoptosis , and angiogenesis in the prostatectomy tissue did not differ between the treatment arms . The proportion of subjects who had a decrease in Gleason score between biopsy and surgical specimens was greater in those on polyphenon E but was not statistically significant . The study 's findings of low bioavailability and /or bioaccumulation of green tea polyphenols  in prostate tissue and statistically insignificant changes in systemic and tissue biomarkers from 3 to 6 weeks of administration suggests that prostate cancer preventive activity of green tea polyphenols , if occurring , may be through indirect means and /or that the activity may need to be evaluated with longer intervention duration s , repeated dosing , or in patients at earlier stages of the disease . Cancer Prev Res ; 5(2 ) ; 290–8 . © 2011 AACR In a prospect i ve study of 19 561 Japanese men , green-tea intake was not associated with a lower risk of prostate cancer ( 110 cases ) , the multivariate hazard ratio for men drinking ⩾5 cups compared with < 1 cup per day being 0.85 ( 95 % confidence interval 0.50–1.43 , trend P=0.81 ) PURPOSE To evaluate the efficacy and toxicity of green tea , prescribed as an alternative complementary ( CAM ) formulation on hormone refractory prostate cancer ( HRPC ) . METHODS Patients with HRCP were prescribed green tea extract capsules at a dose level of 250 mg twice daily . Efficacy and toxicity were evaluated during monthly visits . The primary endpoint was prostate-specific antigen ( PSA ) or measurable disease progression after a minimum of 2 months of therapy . RESULTS Nineteen patients were enrolled into the study . The treatment was generally well tolerated . Twelve patients reported at least one side effect ; only two of these were of moderate or severe grade . Primary toxicity was related to gastrointestinal irritation or caffeine intake . Four patients did not complete the minimum 2 months of therapy because of : intolerance ( two patients ) , physician stoppage ( one patient ) , death from cerebrovascular accident ( one patient ) . Fifteen patients completed at least 2 months of therapy . Nine of these patients had progressive disease within 2 months of starting therapy . Six patients developed progressive disease after additional 1 to 4 months of therapy . CONCLUSION Green tea , as CAM therapy , was found to have minimal clinical activity against hormone refractory prostate cancer Background and aims . It has been hypothesized that some aspect of a traditional ‘ Asian ’ diet , that is low in animal products and high in soya , may be associated with a reduced risk of prostate cancer . This study aim ed to examine the association between dietary intake and prostate cancer risk among 18,115 men in Hiroshima and Nagasaki , Japan , using prospect i ve data from the Life Span Study . Methods : Subjects completed a food-frequency question naire at baseline ( 1963 , 1965 and /or 1979 ) and were followed for incident prostate cancer until 
    Output:
    
Findings demonstrate that green tea appears to be an effective chemopreventive agent , particularly in those with high- grade prostate intraepithelial neoplasia .
However , evidence of efficacy in the treatment of PCa is currently lacking .