Factors related to enrollment in the breast cancer prevention trial at a comprehensive cancer center during the first year of recruitment.

BACKGROUND: Using an a priori theoretic model of behavior change, factors predicting enrollment in a randomized chemoprevention trial during the first year of recruitment were assessed prospectively. METHODS: Eligible participants were asked to complete a 90-item semistructured questionnaire after attendance at an informational meeting. Components of the Health Belief Model (including perceived susceptibility, perceived severity, perceived benefits and barriers, cues to action, and health motivation), health status, preventive health behaviors, and social influence were assessed in relation to enrollment. RESULTS: Overall, 331 women attended one of the meetings, and 73% completed a questionnaire; 45% enrolled on the trial and 55% did not. In bivariate analyses, all but one of the perceived barriers were associated negatively with enrollment; however, items assessing perceived susceptibility, perceived severity, and perceived benefits were not. Nonparticipants also were more likely to be over 49 years of age, to be currently or to have been on estrogen replacement therapy, and to have had hot flashes. In logistic regression analysis, not being able to take estrogen replacement therapy was the strongest predictor of nonparticipation (odds ratio [OR], 12.13, 95% confidence interval [CI], 3.63, 40.60). Other factors associated with nonparticipation were concern about side effects of tamoxifen (OR, 5.06; CI, 2.37, 10.80); the possibility of getting a placebo (OR, 7.75; CI, 1.51, 39.67); the costs associated with the trial (OR, 3.21; CI, 1.12, 9.24); and absence of concern that significant others would be reassured if the respondent was taking tamoxifen (OR, 2.58; CI, 1.04, 6.41). CONCLUSIONS: These findings support the view that recruitment efforts for chemoprevention trials should address barriers specific to their circumstances. In addition, increasing the support available from personal social networks may enhance recruitment to chemoprevention trials for breast cancer.

A clinical cancer prevention curriculum in a comprehensive cancer center.

Interns, residents, and medical students who spend one month at a comprehensive cancer center are presented with a strategy to incorporate cancer preventive services into their outpatient practices. This is accomplished through didactic lectures in clinical epidemiology. Terms that are essential to an understanding of disease occurrence are defined including incidence, prevalence, and mortality rate. Odds and probability are explored with the introduction of the odds ratio and the identification of risk factors. Primary and secondary cancer prevention are defined, and parameters related to cancer screening are introduced (sensitivity, specificity, prevalence, and positive predictive value). Risk factors for malignancy are identified where they are known and can be modified. Primary prevention strategies are reviewed by site along with data that support or refute recommendations for site-specific screening. Medical conditions and risk factor profiles that define high-risk groups are reviewed. Trainees are given copies of the US Preventive Services Task Force screening recommendations and a clinical handbook. The impact of this information on clinical practice patterns remains to be evaluated.

Dietary epidemiology of colon cancer.

Epidemiologic studies of the relationship of diet to cancer etiology are hampered by methodologic difficulties which can be overcome by careful trial design. The use of appropriate dietary assessment instruments is necessary to minimize bias and improve accuracy of diet assessment. Population studies implicate dietary fat intake in the etiology of colorectal carcinogenesis, and the incidence of colorectal malignancies around the world is positively correlated with meat and fat consumption and total calorie intake. Retrospective studies of fat intake yield equivocal results, whereas prospective studies have failed to show a relationship between fat intake and colon cancer risk. An inverse relationship exists between fiber consumption and colorectal cancer incidence and mortality rates. The positive observational studies are supported by laboratory studies of experimental carcinogenesis which show a greater number of tumors in animals fed high-fat or high-calorie diets. Increased fiber intake appears to offer some protection against colorectal cancer. Plausible mechanisms have been proposed in animals for the role of fat and fiber in colorectal carcinogenesis; the mechanisms in human populations await further description. The interrelationships between fat consumption and consumption of dietary fiber and micronutrients have made it difficult to assess the roles of these substances in the etiology of colorectal cancer. Calcium offers protection in animal systems, and the data in humans are suggestive but not yet conclusive. Data on the role of alcohol in colorectal carcinogenesis remain inconclusive. Little evidence exists for a protective effect of retinoids and carotenoids; the evidence for selenium and vitamin C is limited and evolving.