Search

Clinical trials have shown that calcium supplementation modestly decreases the risk of colorectal adenomas. However, few studies have examined the effect of calcium on the risk of different types of colorectal lesions or dietary determinants of this effect. Our analysis used patients from the Calcium Polyp Prevention Study, a randomized, double-blind, placebo-controlled chemoprevention trial among patients with a recent colorectal adenoma. Nine hundred thirty patients were randomly assigned to calcium carbonate (1200 mg/day) or placebo. Follow-up colonoscopies were conducted approximately 1 and 4 years after the qualifying examination. We used general estimating equation (GEE) and generalized linear regression analyses to compute risk ratios and 95% confidence intervals (CIs) to assess the effect of calcium treatment versus placebo on the risk of hyperplastic polyps, tubular adenomas, and more advanced lesions. Additionally, we used GEE analyses to compare the calcium treatment effects for various types of polyps with that for tubular adenomas. We also examined the interaction between calcium treatment and baseline in- take of dietary calcium, fat, and fiber. All P values were obtained using Wald tests based on the corresponding models. All tests of statistical significance were two-sided. Results: The calcium risk ratio for hyperplastic polyps was 0.82 (95% CI = 0.67 to 1.00), that for tubular adenomas was 0.89 (95 % CI = 0.77 to 1.03), and that for histologically advanced neoplasms was 0.65 (95 % CI = 0.46 to 0.93) compared with patients assigned to placebo. There were no statistically significant differences between the risk ratio for tubular adenomas and that for other types of polyps. The effect of calcium supplementation on adenoma risk was most pronounced among individuals with high dietary intakes of calcium and fiber and with low intake of fat, but the interactions were not statistically significant. Our results suggest that calcium supplementation may have a more pronounced antineoplastic effect on advanced colorectal lesions than on other types of polyps. [ABSTRACT FROM AUTHOR]

Background: In two large, randomized prevention trials, supplementation with β-carotene increased the risk of lung cancer. Subjects in these studies were predominantly cigarette smokers, and the adverse effects were concentrated among those who also drank alcohol. Although β-carotene supplementation appeared not to increase the risk of cancer generally, it is not clear if smoking and/or alcohol use alters the effect of β-carotene on carcinogenesis at sites outside the lung. Methods: We studied the effect of β-carotene supplementation on colorectal adenoma recurrence among subjects in a multicenter double-blind, placebo-controlled clinical trial of antioxidants for the prevention of colorectal adenomas. A total of 864 subjects who had had an adenoma removed and were polyp-free were randomly assigned (in a factorial design) to receive β-carotene (25 mg or placebo) and/or vitamins C and E in combination (1000 mg and 400 mg, respectively, or placebo), and were followed with colonoscopy for adenoma recurrence 1 year and 4 years after the qualifying endoscopy. A total of 707 subjects had two followup examinations and provided smoking and alcohol use data. Adjusted multivariate risk ratios (RRs) and 95% confidence intervals (CIs) were used to assess the effects of β-carotene on adenoma recurrence. Results: Among subjects who neither smoked cigarettes nor drank alcohol, β-carotene was associated with a marked decrease in the risk of one or more recurrent adenomas (RR = 0.56, 95 % CI = 0.35 to 0.89), but β-carotene supplementation conferred a modest increase in the risk of recurrence among those who smoked (RR = 1.36, 95% CI = 0.70 to 2.62) or drank (RR = 1.13, 95% CI = 0.89 to 1.43). For participants who smoked cigarettes and also drank more than one alcoholic drink per day, β-carotene doubled the risk of adenoma recurrence (RR = 2.07, 95% CI = 1.39 to 3.08; P for difference from nonsmoker/nondrinker RR < .001). Conclusion:... [ABSTRACT FROM AUTHOR]

Background: In two large, randomized prevention trials, supplementation with beta-carotene increased the risk of lung cancer. Subjects in these studies were predominantly cigarette smokers, and the adverse effects were concentrated among those who also drank alcohol. Although beta-carotene supplementation appeared not to increase the risk of cancer generally, it is not clear if smoking and/or alcohol use alters the effect of beta-carotene on carcinogenesis at sites outside the lung.Methods: We studied the effect of beta-carotene supplementation on colorectal adenoma recurrence among subjects in a multicenter double-blind, placebo-controlled clinical trial of antioxidants for the prevention of colorectal adenomas. A total of 864 subjects who had had an adenoma removed and were polyp-free were randomly assigned (in a factorial design) to receive beta-carotene (25 mg or placebo) and/or vitamins C and E in combination (1000 mg and 400 mg, respectively, or placebo), and were followed with colonoscopy for adenoma recurrence 1 year and 4 years after the qualifying endoscopy. A total of 707 subjects had two follow-up examinations and provided smoking and alcohol use data. Adjusted multivariate risk ratios (RRs) and 95% confidence intervals (CIs) were used to assess the effects of beta-carotene on adenoma recurrence.Results: Among subjects who neither smoked cigarettes nor drank alcohol, beta-carotene was associated with a marked decrease in the risk of one or more recurrent adenomas (RR = 0.56, 95% CI = 0.35 to 0.89), but beta-carotene supplementation conferred a modest increase in the risk of recurrence among those who smoked (RR = 1.36, 95% CI = 0.70 to 2.62) or drank (RR = 1.13, 95% CI = 0.89 to 1.43). For participants who smoked cigarettes and also drank more than one alcoholic drink per day, beta-carotene doubled the risk of adenoma recurrence (RR = 2.07, 95% CI = 1.39 to 3.08; P for difference from nonsmoker/nondrinker RR <.001).Conclusion: Alcohol intake and cigarette smoking appear to modify the effect of beta-carotene supplementation on the risk of colorectal adenoma recurrence. [ABSTRACT FROM AUTHOR]

Focuses on a study which focused on breast cancer and examined the association between being breast-fed as an infant, and the breast cancer risk among women. Speculation of an infectious etiology for breast cancer in humans; Transmission of mammary tumor virus via breast milk; Methodology used to conduct the study; Results of the study.

Editorial. Looks at steps for evaluating the clinical and economic trade-offs of hepatic arterial infusion (HAI). Determining quality-adjusted survival; Components of the Quality-Adjusted Time Without Symptoms and Toxicity (Q-TWiST); Cost comparison between HAI and intravenous chemotherapy (IVC).