***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: BACKGROUND Red meat and processed meat consumption have been associated with increased risk of colorectal cancer  in some , but not all , relevant cohort studies . Evidence on the relationship between risk of colorectal cancer and poultry and fish consumption is inconsistent . METHODS We conducted a prospect i ve cohort study of 37,112 residents of Melbourne , Australia recruited from 1990 to 1994 . Diet was measured with a food frequency question naire . We categorized the frequency of fresh red meat , processed meat , chicken , and fish consumption into approximate quartiles . Adenocarcinomas of the colon or rectum were ascertained via the Victorian Cancer Registry . RESULTS We identified 283 colon cancers and 169 rectal cancers in an average of 9 years of follow-up . For rectal cancer , the hazard ratios [ 95 % confidence intervals ( 95 % CI ) ] in the highest quartile of consumption of fresh red meat and processed meat were 2.3 ( 1.2 - 4.2 ; P for trend = 0.07 ) and 2.0 ( 1.1 - 3.4 ; P for trend = 0.09 ) , respectively . The corresponding hazard ratios ( 95 % CIs ) for colon cancer were 1.1 ( 0.7 - 1.6 ; P for trend = 0.9 ) and 1.3 ( 0.9 - 1.9 ; P for trend = 0.06 ) . However , for neither type of meat was the heterogeneity between subsites significant . Chicken consumption was weakly negatively associated with colorectal cancer ( hazard ratio highest quartile , 0.7 ; 95 % CI , 0.6 - 1.0 ; P for trend = 0.03 ) , whereas hazard ratios for fish consumption were close to unity . CONCLUSION Consumption of fresh red meat and processed meat seemed to be associated with an increased risk of rectal cancer . Consumption of chicken and fish did not increase risk BACKGROUND The hypothesis that increased intake of dietary fibre lowers the risk of colorectal cancer ( CRC ) has recently been weakened by results from cohort and intervention studies that did not detect such an association . We investigated the association between  dietary fibre intake  and risk of CRC in a cohort of women that prospect ively answered a food frequency question naire ( FFQ ) . METHODS We studied 45 491 women in the Breast Cancer Detection Demonstration Project ( BCDDP ) follow-up cohort . A 62-item FFQ was administered from 1987 and 1989 to assess dietary intake . Participants received follow-up question naires ( in 1992 - 1995 and 1995 - 1998 ) on which they reported incident cancers . Cases were also identified through search es of the National Death Index and state cancer registries . Cox proportional hazard regression was used to generate risk ratios and 95 % CI for quintiles of total fibre intake and fibre subtypes . RESULTS During a mean follow-up time of 8.5 years we identified 487 colorectal cancer cases . The 10th and 90th percentiles of dietary fibre intake were 5.4 g and 18.2 g respectively . For total fibre we observed no association with colorectal cancer ( fifth versus first quintile , RR = 0.94 , 95 % CI : 0.71 - 1.23 ) . Analyses by subgroup of fibre and by anatomical subsite did not reveal any stronger inverse associations . CONCLUSIONS Within a cohort of older women characterized by a relatively low fibre intake , there was little evidence that dietary fibre intake lowers the risk of colorectal cancer CONTEXT Basic research and observational evidence as well as results from trials of colon polyp recurrence suggest a role for aspirin in the chemoprevention of cancer . OBJECTIVE To examine the effect of aspirin on the risk of cancer among healthy women . DESIGN , SETTING , AND PARTICIPANTS In the Women 's Health Study , a r and omized 2 x 2 factorial trial of aspirin and vitamin E conducted between September 1992 and March 2004 , 39 876 US women aged at least 45 years and initially without previous history of cancer , cardiovascular disease , or other major chronic illness were r and omly assigned to receive either aspirin or aspirin placebo and followed up for an average of 10.1 years . INTERVENTION A dose of 100 mg of aspirin ( n=19 934 ) or aspirin placebo ( n=19 942 ) administered every other day . MAIN OUTCOME MEASURES Confirmed newly diagnosed invasive cancer at any site , except for nonmelanoma skin cancer . Incidence of breast , colorectal , and lung cancer were secondary end points . RESULTS No effect of aspirin was observed on total cancer ( n = 2865 ; relative risk [ RR ] , 1.01 ; 95 % confidence interval [ CI ] , 0.94 - 1.08 ; P = .87 ) , breast cancer ( n = 1230 ; RR , 0.98 ; 95 % CI , 0.87 - 1.09 ; P = .68 ) , colorectal cancer ( n = 269 ; RR , 0.97 ; 95 % CI , 0.77 - 1.24 ; P = .83 ) , or cancer of any other site , with the exception of lung cancer for which there was a trend toward reduction in risk ( n = 205 ; RR , 0.78 ; 95 % CI , 0.59 - 1.03 ; P = .08 ) . There was also no reduction in cancer mortality either overall ( n = 583 ; RR , 0.95 ; 95 % CI , 0.81 - 1.11 ; P = .51 ) or by site , except for lung cancer mortality ( n = 140 ; RR , 0.70 ; 95 % CI , 0.50 - 0.99 ; P = .04 ) . No evidence of differential effects of aspirin by follow-up time or interaction with vitamin E was found . CONCLUSIONS Results from this large-scale , long-term trial suggest that alternate day use of low-dose aspirin ( 100 mg ) for an average 10 years of treatment does not lower risk of total , breast , colorectal , or other site-specific cancers . A protective effect on lung cancer or a benefit of higher doses of aspirin can not be ruled out Background : Evidence from laboratory and animal studies suggests that high fish consumption may reduce the risk of colorectal cancer , but the results of studies in humans have been inconsistent . The objective of this study was to prospect ively examine the association between fish consumption and the  risk of colorectal cancer incidence in Japan , where fish is widely consumed . Methods : We analysed data from 39 498 men and women registered in the Ohsaki National Health Insurance Cohort Study who were 40–79 years old and free of cancer at the baseline .  Fish consumption was assessed at the baseline using a self-administered food frequency question naire . Results : During 9 years of follow-up , we identified 566 incident cases of colorectal cancer ( 379 men and 187 women ) . The hazard ratios and 95 % confidence intervals ( CIs ) for colorectal cancer incidence in the highest quartile of fish consumption compared with the lowest quartile were 1.07 ( 95 % CIs ; 0.78–1.46 , P-trend=0.43 ) for men , and 0.96 ( 95 % CIs ; 0.61–1.53 , P-trend=0.69 ) for women . Conclusion : The results of this prospect i ve cohort study revealed no association between fish consumption and the risk of colorectal cancer Background : Fish is the main dietary source of long-chain n-3 fatty acids , which have been suggested to play a protective role in colorectal cancer development in laboratory and animal studies . Human studies have not shown consistent results . We examined the association between intakes of fish and n-3 fatty acids from fish and  colorectal cancer risk in men enrolled in the Physicians ' Health Study . Methods : The Physicians ' Health Study began as a r and omized trial to examine the effect of aspirin and β-carotene supplementation on cancer and cardiovascular disease . Fish intake was assessed at the 12-month follow-up with an abbreviated food-frequency question naire . Cox proportional hazards models were used to estimate multivariate relative risks for colorectal cancer for the categories of fish intake and quartiles of n-3 fatty acid intake . Results : During 22 years of follow-up , 500 men had a confirmed diagnosis of colorectal cancer . Fish intake was inversely associated with colorectal cancer risk [ multivariate relative risk ( 95 % confidence interval ) for highest versus lowest category , 0.60 ( 0.40 - 0.91 ) ; Ptrend = 0.01 ] . The inverse association was observed for both colon and rectal cancers . Our findings for n-3 fatty acids were similar to those for fish ; the multivariate relative risk ( 95 % confidence interval ) of total colorectal cancer for the highest versus lowest quartile of n-3 fatty acids was 0.74 ( 0.57 - 0.95 ; Ptrend = 0.01 ) . Conclusions : Our results from this long-term prospect i ve study suggest that intakes of fish and long-chain n-3 fatty acids from fish may decrease the risk for colorectal cancer . ( Cancer Epidemiol Biomarkers Prev 2008;17(5):1136–43 CONTEXT Observational studies and polyp recurrence trials are not conclusive regarding the effects of a low-fat dietary pattern on risk of colorectal cancer , necessitating a primary prevention trial . OBJECTIVE To evaluate the effects of a low-fat eating pattern on risk of colorectal cancer in postmenopausal women . DESIGN , SETTING , AND PARTICIPANTS The Women 's Health Initiative Dietary Modification Trial , a r and omized controlled trial conducted in 48,835 postmenopausal women aged 50 to 79 years recruited between 1993 and 1998 from 40 clinical centers throughout the United States . INTERVENTIONS Participants were r and omly assigned to the  dietary modification intervention  ( n = 19,541 ; 40 % ) or the  comparison group  ( n = 29,294 ; 60 % ) . The intensive behavioral modification program aim ed to motivate and support reductions in dietary fat , to increase consumption of vegetables and fruits , and to increase grain servings by using group sessions , self-monitoring techniques , and other tailored and targeted strategies . Women in the comparison group continued their usual eating pattern . MAIN OUTCOME MEASURE Invasive colorectal cancer incidence . RESULTS A total of 480 incident cases of invasive colorectal cancer occurred during a mean follow-up of 8.1 ( SD , 1.7 ) years . Intervention group participants significantly reduced their percentage of energy from fat by 10.7 % more than did the comparison group at 1 year , and this difference between groups was mostly maintained ( 8.1 % at year 6 ) . Statistically significant increases in vegetable , fruit , and grain servings were also made . Despite these dietary changes , there was no evidence that the intervention reduced the risk of invasive colorectal cancer during the follow-up period . There were 201 women with invasive colorectal cancer ( 0.13 % per year ) in the intervention group and 279 ( 0.12 % per year ) in the comparison group ( hazard ratio , 1.08 ; 95 % confidence interval , 0.90 - 1.29 ) . Secondary analyses suggested potential interactions with baseline aspirin use and combined estrogen-progestin use status ( P = .01 for each ) . Colorectal examination rates , although not protocol defined , were comparable between the intervention and comparison groups . Similar results were seen in analyses adjusting for adherence to the intervention . CONCLUSION In this study , a low-fat dietary pattern intervention did not reduce the risk of colorectal cancer  in postmenopausal women during 8.1 years of follow-up . CLINICAL TRIALS REGISTRATION Clinical Trials.gov Identifier : NCT00000611 BACKGROUND We tested the hypothesis that dietary intervention can inhibit the development of recurrent colorectal adenomas , which are precursors of most large-bowel cancers . METHODS We r and omly assigned 2079 men and women who were 35 years of age or older and who had had one or more histologically confirmed colorectal adenomas removed within six months before r and omization to one of two groups : an intervention group given intensive counseling and assigned to follow a diet that was low in fat ( 20 percent of total calories ) and high in fiber ( 18 g of dietary fiber per 1000 kcal ) and fruits and vegetables ( 3.5 servings per 1000 kcal ) , and a control group given a st and ard brochure on healthy eating and assigned to follow their usual diet . Subjects entered the study after undergoing complete colonoscopy and removal of adenomatous polyps ; they remained in the study for approximately four years , undergoing colonoscopy one and four years after r and omization . RESULTS A total of 1905 of the r and omized subjects ( 91.6 percent ) completed the study . Of the 958 subjects in the 
    Output:
    
RESULTS There is convincing evidence that intake of garlic , vitamin B6 and magnesium , active living , maintaining a healthy weight and waist , avoiding or reducing red meat , alcohol , and smoking , as well as hormone replacement therapy among women may significantly protect against developing colorectal cancer .
There is less consistent evidence for fruit and vegetable intake ( fiber and folate ) , fish and Omega-3 fatty acids , selenium , dairy , calcium and vitamin D. For high-risk population s , aspirin have been shown to protect against the development of colonic adenomas and CRC , while a minimal effective dose remains unclear .
Colorectal cancer can be prevented in general population through dietary and lifestyle interventions , and aspirin may be a good choice of chemoprevention agent among high risk individuals