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Background Results of epidemiological studies of dietary fiber and colorectal cancer risk have not been consistent, possibly because of attenuation of associations due to measurement error in dietary exposure ascertainment. Methods To examine the association between dietary fiber intake and colorectal cancer risk, we conducted a prospective case-control study nested within seven UK cohort studies, which included 579 case patients who developed incident colorectal cancer and 1996 matched control subjects. We used standardized dietary data obtained from 4- to 7-day food diaries that were completed by all participants to calculate the odds ratios for colorectal, colon, and rectal cancers with the use of conditional logistic regression models that adjusted for relevant covariates. We also calculated odds ratios for colorectal cancer by using dietary data obtained from food-frequency questionnaires that were completed by most participants. All statistical tests were two-sided. Results Intakes of absolute fiber and of fiber intake density, ascertained by food diaries, were statistically significantly inversely associated with the risks of colorectal and colon cancers in both age-adjusted models and multivariable models that adjusted for age; anthropomorphic and socioeconomic factors; and dietary intakes of folate, alcohol, and energy. For example, the multivariable-adjusted odds ratio of colorectal cancer for highest vs the lowest quintile of fiber intake density was 0.66 (95% confidence interval = 0.45 to 0.96). However, no statistically significant association was observed when the same analysis was conducted using dietary data obtained by food-frequency questionnaire (multivariable odds ratio = 0.88, 95% confidence interval = 0.57 to 1.36). Conclusions Intake of dietary fiber is inversely associated with colorectal cancer risk. Methodological differences (ie, study design, dietary assessment instruments, definition of fiber} may account for the lack of convincing evidence for the inverse association between fiber intake and colorectal cancer risk in some previous studies. DOI: 10.1093/jnci/djq092

Background: Experimental data from animals suggest a protective role for the pineal hormone melatonin in the etiology of breast cancer, but results from the few retrospective case-control studies that examined the association in humans have been inconsistent. To determine whether low levels of endogenous melatonin are associated with an increased risk for developing breast cancer, we conducted a prospective nested case-control study among British women. Methods: Concentrations of 6-sulfatoxymelatonin, the main metabolite of melatonin in urine and a validated marker of circulating melatonin levels, were measured by radioimmunoassay in 24-hour urine samples collected from women shortly after enrollment in the prospective Guernsey III Study. Levels of 6-sulfatoxymelatonin were compared among 127 patients diagnosed with breast cancer during follow-up and among 353 control subjects, matched for age, recruitment date, menopausal status, and day of menstrual cycle for premenopausal women or number of years postmenopausal for postmenopausal women. Associations were examined by analyses of covariance and conditional logistic regression. All tests of statistical significance were two-sided. Results: No statistically significant differences in urinary 6-sulfatoxymelatonin concentrations were observed between women who developed breast cancer and control subjects among premenopausal or postmenopausal women (P = .8 and P = .9, respectively). When data from premenopausal and postmenopausal women were combined in a multivariable analysis adjusted for potential confounders and grouped into three categories defined by 6-suifatoxymelatonin tertiles of control subjects, the level of 6-sulfatoxymelatonin excreted was not statistically significantly associated with the risk of breast cancer (odds ratio [OR] for breast cancer = 0.95, 95% confidence interval [CI] = 0.55 to 1.65, comparing the middle category with the lowest category of 6-sulfatoxymelatonin concentration, and OR = 0.99, 95% CI = 0.58 to 1.70, comparing the highest category with the lowest category). Conclusion: We found no evidence that the level of melatonin is strongly associated with the risk for breast cancer.

Background: Breast-conserving therapy (BCT) has been shown to be as effective as mastectomy in the treatment of tumors 2 cm or smaller. However, evidence of its efficacy, over the long term, in patients with tumors larger than 2 cm is limited. From May 1980 to May 1986, the European Organization for Research and Treatment of Cancer carried out a randomized, multicenter trial comparing BCT with modified radical mastectomy for patients with tumors up to 5 cm. In this analysis, we investigated whether the treatments resulted in different overall survival, time to distant metastasis, or time to locoregional recurrence. Methods: Of 868 eligible breast cancer patients randomly assigned to the BCT arm or to the modified radical mastectomy arm, 80% had a tumor of 2.1-5 cm. BCT comprised lumpectomy with an attempted margin of 1 cm of healthy tissue and complete axillary clearance, followed by radiotherapy to the breast and a supplementary dose to the tumor bed. The median follow-up was 13.4 years. All P values are two-sided. Results: At 10 years, there was no difference between the two groups in overall survival (66% for the mastectomy patients and 65% for the BCT patients; P = .11) or in their distant metastasis-free rates (66% for the mastectomy patients and 61% for the BCT patients; P = .24). The rate of locoregional recurrence (occurring before or at the same time as distant metastasis) at 10 years did show a statistically significant difference (12% of the mastectomy and 20% of the BCT patients; P = .01). Conclusions: BCT and mastectomy demonstrate similar survival rates in a trial in which the great majority of the patients had stage II breast cancer. [J Natl Cancer Inst 2000;92:1143-50]

Trials needed to decide right treatment Ductal carcinoma is situ of the breast used to be thought a relatively rare condition. Often it was not distinguished from invasive cancer, and [...]