***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 
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    Input: Purpose Epidemiologic studies suggest that consumption of green tea may have a protective effect against the development of several cancers . Pre clinical studies of green tea and its polyphenolic components have demonstrated antimutagenic and anticarcinogenic activity , and inhibition of growth of tumor cell lines and animal tumor models , including lung cancer . Green tea may also have chemopreventive properties , and enhancement of cytotoxicity of chemotherapeutic agents has been demonstrated . This trial was design ed to determine the maximum tolerated dose ( MTD ) of green tea extract ( GTE ) in patients with advanced lung cancer . Methods A total of 17 patients with advanced lung cancer were registered to receive once-daily oral dosing of GTE at a starting dose of 0.5 g/m2 per day , with an accelerated dose-escalation scheme . Results On this schedule , the MTD of GTE was 3 g/m2 per day , and at this dose ,  GTE  was well tolerated with no grade 3 or 4 toxicity seen . Dose-limiting toxicities were diarrhea , nausea and hypertension . No objective responses were seen in this trial . Seven patients had stable disease ranging from 4 to 16 weeks ; no patient remained on therapy longer than 16 weeks due to the development of progressive disease . Conclusions This study suggests that while relatively nontoxic at a dose of 3 g/m2 per day , GTE likely has limited activity as a cytotoxic agent , and further study of GTE as a single-agent in established malignancies may not be warranted . Further studies should focus on the potential chemopreventive and chemotherapy-enhancing properties of GTE In a pooled analysis of two prospect i ve studies with 35 004 Japanese women , green-tea intake was not associated with a lower risk of breast cancer ( 222 cases ) , the multivariate relative risk for women drinking ⩾5 cups compared with < 1 cup per day being 0.84 ( 95 % confidence interval 0.57–1.24 , Trend P=0.69 ) We conducted a population -based case-control study of patients with bladder cancer and of controls drawn r and omly from the general population of Metropolitan Nagoya and interviewed both groups . The incidence rates of bladder cancer were 2.42 and 7.05/100,000 for females and males , respectively . The analysis , based on 293 patients and 589 controls who were frequency matched for age , sex , and residence , provided the following major findings . Age-adjusted relative risks of 1.89 ( 1.15 - 3.10 ) and 3.53 ( 1.71 - 7.27 ) were found in male and female cigarette smokers , respectively . Significant relative risk was also found in males who drank cocoa . Elevated risk with a dose-response relationship was observed among women who used hair dye and who smoke , but this risk was insignificant , with the disappearance of a dose-response relationship , when it was adjusted for smoking . Age- and smoking-adjusted relative risk of coffee drinking was insignificant with no dose-response relationship . Relative risk of artificial sweetener use was below 1 with adjustment for age and smoking . Intake of alcoholic beverages and cola  was insignificantly associated . Reduced risk of significance was suggested for the intake of black tea and matcha ( powdered green tea ) in females and of fruit juice in males CONTEXT Green tea polyphenols have been extensively studied as cardiovascular disease and cancer chemopreventive agents in vitro and in animal studies . However , the effects of green tea consumption in humans remain unclear . OBJECTIVE To investigate the associations between green tea consumption and all-cause and cause-specific mortality . DESIGN , SETTING , AND PARTICIPANTS The Ohsaki National Health Insurance Cohort Study , a population -based , prospect i ve cohort study initiated in 1994 among 40,530 Japanese adults aged 40 to 79 years without history of stroke , coronary heart disease , or cancer at baseline . Participants were followed up for up to 11 years ( 1995 - 2005 ) for all-cause mortality and for up to 7 years ( 1995 - 2001 ) for cause-specific mortality . MAIN OUTCOME MEASURES Mortality due to cardiovascular disease , cancer , and all causes . RESULTS Over 11 years of follow-up ( follow-up rate , 86.1 % ) , 4209 participants died , and over 7 years of follow-up ( follow-up rate , 89.6 % ) , 892 participants died of cardiovascular disease and 1134 participants died of cancer .  Green tea consumption was inversely associated with mortality due to all causes and due to cardiovascular disease . The inverse association with all-cause mortality was stronger in women ( P = .03 for interaction with sex ) . In men , the multivariate hazard ratios of mortality due to all causes associated with different green tea consumption frequencies were 1.00 ( reference ) for less than 1 cup/d , 0.93 ( 95 % confidence interval [ CI ] , 0.83 - 1.05 ) for 1 to 2 cups/d , 0.95 ( 95 % CI , 0.85 - 1.06 ) for 3 to 4 cups/d , and 0.88 ( 95 % CI , 0.79 - 0.98 ) for 5 or more cups/d , respectively ( P = .03 for trend ) . The corresponding data for women were 1.00 , 0.98 ( 95 % CI , 0.84 - 1.15 ) , 0.82 ( 95 % CI , 0.70 - 0.95 ) , and 0.77 ( 95 % CI , 0.67 - 0.89 ) , respectively ( P<.001 for trend ) . The inverse association with cardiovascular disease mortality was stronger than that with all-cause mortality . This inverse association was also stronger in women ( P = .08 for interaction with sex ) . In women , the multivariate hazard ratios of cardiovascular disease mortality across increasing green tea consumption categories were 1.00 , 0.84 ( 95 % CI , 0.63 - 1.12 ) , 0.69 ( 95 % CI , 0.52 - 0.93 ) , and 0.69 ( 95 % CI , 0.53 - 0.90 ) , respectively ( P = .004 for trend ) . Among the types of cardiovascular disease mortality , the strongest inverse association was observed for stroke mortality . In contrast , the hazard ratios of cancer mortality were not significantly different from 1.00 in all green tea categories compared with the lowest-consumption category . CONCLUSION Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer Tea drinking has been associated with decreased occurrence of cancer and heart disease . One potential mechanism for these findings is the strong antioxidant effect of tea polyphenols . A phase II r and omized controlled tea intervention trial was design ed to study the effect of high consumption ( 4 cups/d ) of decaffeinated green or black tea on oxidative DNA damage as measured by urinary 8-hydroxydeoxyguanosine ( 8-OHdG ) among smokers over a 4-mo period . A total of 143 heavy smokers , aged 18 - 79 y , were r and omized to drink either green or black tea or water . Levels of plasma and urinary catechins and urinary 8-OHdG were measured monthly . A total of 133 of 143 smokers completed the 4-mo intervention . Multiple linear regression models were used to estimate the main effects and interaction effect of green and black tea consumption on creatinine-adjusted urinary 8-OHdG , with or without adjustment for potential confounders . Plasma and urinary levels of catechins rose significantly in the green tea group compared with the other two groups . Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed a highly significant decrease in urinary 8-OHdG ( -31 % ) after 4 mo of drinking decaffeinated green tea ( P = 0.002 ) . No change in urinary 8-OHdG was seen among smokers assigned to the black tea group . These data suggest that regular green tea drinking might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking Modulation of urinary excretion of green tea polyphenols ( GTPs ) and oxidative DNA damage biomarker , 8-hydroxydeoxyguanosine ( 8-OHdG ) , were assessed in urine sample s collected from a r and omized , double-blinded and  placebo-controlled phase IIa chemoprevention trial with GTP in 124 individuals . These individuals were sero-positive for both HBsAg and aflatoxin-albumin adducts , and took GTP capsules daily at doses of 500 mg , 1000 mg or a placebo for 3 months . Twenty-four hour urine sample s were collected before the intervention and at the first and third month of the study . Urinary excretion of 8-OHdG and GTP components was measured by HPLC-CoulArray electrochemical detection . The baseline levels of 8-OHdG and GTP components among the three groups showed homogeneity ( P > 0.70 ) , and a non-significant fluctuation was observed in the placebo group over the 3 months ( P > 0.30 ) . In GTP-treated groups , epigallocatechin ( EGC ) and epicatechin ( EC ) levels displayed significant and dose-dependent increases in both the 500 mg group and 1000 mg group ( P < 0.05 ) . The 8-OHdG levels did not differ between the three groups at the 1 month collection , with medians of 1.83 , 2.08 and 1.86 ng/mg-creatinine for placebo , 500 and 1000 mg group , respectively ( P = 0.999 ) . At the end of the 3 months ' intervention , 8-OHdG levels decreased significantly in both GTP-treated groups , with medians of 2.02 , 1.03 and 1.15 ng/mg-creatinine for placebo , 500 mg and 1000 mg group , respectively ( P = 0.007 ) . These results suggest that urinary excretions of EGC and EC can serve as practical biomarkers for green tea consumption in human population s. The results also suggest that chemoprevention with GTP is effective in diminishing oxidative DNA damage Our study investigates whether tea consumption can enhance the survival of patients with epithelial ovarian cancer , a prospect i ve cohort study was conducted in Hangzhou , China . The cohort comprised 254 patients recruited during 1999 - 2000 with histopathologically confirmed epithelial ovarian cancer and was followed up for a minimum of 3 years . Two hundred forty four ( 96.1 % ) of the cohort or their close relatives were traced . The variables examined included their survival time and the  frequency and quantity of tea consumed post-diagnosis .  The actual number of deaths was obtained and Cox proportional hazards models were used to obtain hazard ratios and associated 95 % confidence intervals ( CI ) , adjusting for age at diagnosis , locality , BMI , parity , FIGO stage , histologic grade of differentiation , cytology of ascites , residual tumour and chemotherapeutic status . The survival experience was different between tea drinkers and non-drinkers ( p < 0.001 ) . There were 81 ( 77.9 % ) of 104 tea-drinkers who survived to the time of interview , compared to only 67 women ( 47.9 % ) still alive among the 140 non-drinkers . Compared to non-drinkers , the adjusted hazard ratios were 0.55 ( 95 % CI = 0.34 - 0.90 ) for tea-drinkers , 0.43 ( 95 % CI = 0.20 - 0.92 ) for consuming at least 1 cup of green tea/day , 0.44 ( 95 % CI = 0.22 - 0.90 ) for brewing 1 batch or more of green tea/day , 0.40 ( 95 % CI = 0.18 - 0.90 ) for consuming more than 500 g of dried tea leaves/year , and 0.38 ( 95 % CI = 0.15 - 0.97 ) for consuming at least 2 g of dried tea leaves/batch . The corresponding dose-response relationships were significant ( p < 0.05 ) . We conclude that increasing the consumption of green tea post-diagnosis may enhance epithelial ovarian cancer survival 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 
    Output:
    
While some evidence suggests that green tea has beneficial effects on gastrointestinal cancers , the findings are not consistent .
Conclusion Green tea may have beneficial effects on cancer prevention .