| Abstract: |
The Polyp Prevention Trial (PPT) is a randomized clinical trial sponsored by the National Cancer Institute. National Institutes of Health, that tests the relationship between diet and the formation of large bowel adenomatous polyps, the precursor lesion for most large bowel cancers. Approximately 2000 participants from 8 Clinical Centers have been randomized into the trial. Half were assigned to the intervention group and asked to adopt a low-fat (20% of calories from fat), high-fiber (18 grams/1000 kcal), high fruit and vegetable (5 to 8 daily servings) eating plan. Numerous epidemiological studies suggest that these dietary factors may be protective for large bowel cancer. The remaining participants were assigned to the control group, maintaining their usual diet. Registered dietitians play a central and critical role in the PPT. The 4-year intervention program is delivered solely by RDs. The success of the intervention depends to a great degree on the abilities of these nutritionists to deliver the program effectively as well as to help participants sustain a high level of motivation for making long-term dietary changes. In addition, RDs at both the Coordinating Center and at the Clinical Centers play a vital role in ensuring standardization of the delivery and documentation of the intervention program. RDs also have the primary responsibility for administering the baseline and annual dietary assessments and for assuring quality and standardization of dietary assessment activities. The Polyp Prevention Trial provides opportunities not available to RDs working in typical clinical settings. For example, the study design allows for approximately 50 hours of in-person counseling for each participant along with resources to assist participants in making long-term changes. The PPT also presents unique challenges to nutritionists in their multiple roles of providing nutrition education and behavioral counseling; administering dietary assessments; maintaining objectivity and standardization; and performing administrative, organizational, and managerial activities. © 1995 American Dietetic Association. |
