Ignite Creation Date:
2024-05-05 @ 4:53 PM
Last Modification Date:
2024-10-26 @ 9:25 AM
Study NCT ID:
NCT00339625
Status:
COMPLETED
Last Update Posted:
2020-05-15
First Post:
2006-06-19
Brief Title:
Polyp Prevention Trial
Sponsor:
National Cancer Institute NCI
Organization:
National Institutes of Health Clinical Center CC
Study Overview
Official Title:
Polyp Prevention Trial
Status:
COMPLETED
Status Verified Date:
2020-04
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
The primary objective of the Poly Prevention Trial PPT is to determine whether a low fat high fiber high vegetable and fruit eating plan will decrease the recurrence of adenomatous polyps of the large bowel Secondary objectives of the PPT include 1 evaluating the effectiveness of the intervention program with respect to participant achievement of dietary goals 2 examining the relation of dietary change and biochemical markers in blood and 3 assessing the impact of the intervention on quality of life indicators
Detailed Description:
OBJECTIVES
The primary objective of the Polyp Prevention Trial PPT is to determine whether a low fat high fiber high vegetable and fruit eating plan will decrease the recurrence of adenomatous polyps of the large bowel Secondary objectives of the PPT include 1 evaluating the effectiveness of the intervention program with respect to participant achievement of dietary goals 2 examining the relation of dietary change and biochemical markers in blood and 3 assessing the impact of the intervention on quality of life indicators
BACKGROUND
Nearly 60000 men and women will die from large bowel cancer in the United States this year making it the second leading cause of death from malignant disease in this country The evidence that diet plays a key role in large bowel carcinogenesis is strong and growing The PPT was undertaken because it is unlikely with respect to diet and large bowel cancer that any combination of further animal research clinical investigations employing non-neoplastic endpoints or observational epidemiologic studies would be sufficiently persuasive to influence public health policy
A large body of ecologic analytic epidemiologic human metabolic and animal experimental data suggests that three dietary factors increase the risk of large bowel cancer high dietary fat low dietary fiber and low vegetable and fruit intake Previous dietary intervention studies have generally focused on a single nutrient The PPT is unique in that three dietary factors are being investigated simultaneously through intervention with a realistic comprehensive dietary pattern change NCI investigators adopted this multiple-goal dietary intervention strategy in the PPT for several reasons people eat foods not isolated nutrients there may be unknown protective food constituents not encompassed in a single-nutrient intervention and there may well be important synergistic effects of various food components best captured in a comprehensive multifactor dietary pattern Moreover by embracing three promising dietary hypotheses simultaneously the PPT intervention is intended to maximize the possibility of reducing polyp recurrence The direct demonstration of any effect of diet on the large bowel neoplastic process would be a major advance
Large bowel adenomas polyps present a unique opportunity to conduct an intervention trial because of the high prevalence of these lesions in the general population over 30 in adults over 50 years of age the high polyp recurrence rate at least 10 annually in those who have undergone adenoma removal and the strong link between adenomas and cancer the so-called adenoma-carcinoma sequence It is generally accepted that large bowel adenomas are an obligate precursor lesion for most large bowel cancers An intervention reducing the recurrence of large bowel polyps would thus have a strong likelihood of reducing the incidence of large bowel cancer
DESIGN
The PPT is a randomized controlled trial being carried out at eight Clinical Centers in the United States The Data and Nutrition Coordinating Center DNCC is Westat Inc Rockville Maryland The target sample size of 2000 permits the detection with 90 power of a reduction of 24 in the polyp recurrence rate
The dietary goals for the intervention arm are 20 of calories from fat 18g fiber1000 kcal and 5-8 servings of fruits and vegetables the exact number based on caloric intake The usual control diet based on data from national surveys is expected to comprise approximately 35 of calories from fat 10-15 g per day of dietary fiber and 35 servings of vegetables and fruits daily
The overall strategy for the intervention program is to reduce calories from fat and to replace them with calories from fruits vegetables and grains thus increasing dietary fiber intake The intervention program patterned after the approach used in the feasibility phase of the Womens Health Trial integrates nutrition education and behavior modification techniques Although initial counseling sessions are carried out one-on-one by the PPT nutritionists most intervention group members participate in group counseling after the first year
The control group is not offered a nutrition intervention program since the general strategy adopted for this group will be minimum interference with customary diets while collecting nutritional data considered necessary for appropriate comparison with the nutrition intervention group Subjects in the control group are expected to maintain their usual diet
Three different dietary assessment instruments are used in the PPT a modified BlockNCI Food Frequency Questionnaire FFQ Four Day Food Records 4DFR and 24 Hour Recalls
Participants undergo colonoscopy again at one T1 and four T4 years into the study Over 280 endoscopists participating in the PPT carry out the T1 and T4 colonoscopies Although the recurrence of one or more adenomas is the primary endpoint of the study it will also be possible to relate the dietary intervention to number size and histotype of polyps Because some polyps 10-15 tend to be missed at baseline the primary analytic interval on which sample size calculations were based is T1 through T4
The presence of one or more adenomas at the qualifying colonoscopy--a key eligibility factor for PPT--was determined by Clinical Center trial pathologists who had been previously oriented by the central pathologists to PPT pathologic criteria The number size and location of adenomas at baseline was determined by the participating endoscopists To standardize the histologic diagnoses used in endpoint ascertainment the PPT requires that histologic type and extent of atypia be determined by the central pathologists for all lesions removed at baseline T1 and T4
Blood specimens are collected on all participants annually these are analyzed on a 20 participant sample the same individuals for whom the diet records are analyzed for lipids carotenoids and vitamins A and E Blood specimens are also available for other analyses including hormone and molecular genetic analysis
The primary objective of the Polyp Prevention Trial PPT is to determine whether a low fat high fiber high vegetable and fruit eating plan will decrease the recurrence of adenomatous polyps of the large bowel Secondary objectives of the PPT include 1 evaluating the effectiveness of the intervention program with respect to participant achievement of dietary goals 2 examining the relation of dietary change and biochemical markers in blood and 3 assessing the impact of the intervention on quality of life indicators
BACKGROUND
Nearly 60000 men and women will die from large bowel cancer in the United States this year making it the second leading cause of death from malignant disease in this country The evidence that diet plays a key role in large bowel carcinogenesis is strong and growing The PPT was undertaken because it is unlikely with respect to diet and large bowel cancer that any combination of further animal research clinical investigations employing non-neoplastic endpoints or observational epidemiologic studies would be sufficiently persuasive to influence public health policy
A large body of ecologic analytic epidemiologic human metabolic and animal experimental data suggests that three dietary factors increase the risk of large bowel cancer high dietary fat low dietary fiber and low vegetable and fruit intake Previous dietary intervention studies have generally focused on a single nutrient The PPT is unique in that three dietary factors are being investigated simultaneously through intervention with a realistic comprehensive dietary pattern change NCI investigators adopted this multiple-goal dietary intervention strategy in the PPT for several reasons people eat foods not isolated nutrients there may be unknown protective food constituents not encompassed in a single-nutrient intervention and there may well be important synergistic effects of various food components best captured in a comprehensive multifactor dietary pattern Moreover by embracing three promising dietary hypotheses simultaneously the PPT intervention is intended to maximize the possibility of reducing polyp recurrence The direct demonstration of any effect of diet on the large bowel neoplastic process would be a major advance
Large bowel adenomas polyps present a unique opportunity to conduct an intervention trial because of the high prevalence of these lesions in the general population over 30 in adults over 50 years of age the high polyp recurrence rate at least 10 annually in those who have undergone adenoma removal and the strong link between adenomas and cancer the so-called adenoma-carcinoma sequence It is generally accepted that large bowel adenomas are an obligate precursor lesion for most large bowel cancers An intervention reducing the recurrence of large bowel polyps would thus have a strong likelihood of reducing the incidence of large bowel cancer
DESIGN
The PPT is a randomized controlled trial being carried out at eight Clinical Centers in the United States The Data and Nutrition Coordinating Center DNCC is Westat Inc Rockville Maryland The target sample size of 2000 permits the detection with 90 power of a reduction of 24 in the polyp recurrence rate
The dietary goals for the intervention arm are 20 of calories from fat 18g fiber1000 kcal and 5-8 servings of fruits and vegetables the exact number based on caloric intake The usual control diet based on data from national surveys is expected to comprise approximately 35 of calories from fat 10-15 g per day of dietary fiber and 35 servings of vegetables and fruits daily
The overall strategy for the intervention program is to reduce calories from fat and to replace them with calories from fruits vegetables and grains thus increasing dietary fiber intake The intervention program patterned after the approach used in the feasibility phase of the Womens Health Trial integrates nutrition education and behavior modification techniques Although initial counseling sessions are carried out one-on-one by the PPT nutritionists most intervention group members participate in group counseling after the first year
The control group is not offered a nutrition intervention program since the general strategy adopted for this group will be minimum interference with customary diets while collecting nutritional data considered necessary for appropriate comparison with the nutrition intervention group Subjects in the control group are expected to maintain their usual diet
Three different dietary assessment instruments are used in the PPT a modified BlockNCI Food Frequency Questionnaire FFQ Four Day Food Records 4DFR and 24 Hour Recalls
Participants undergo colonoscopy again at one T1 and four T4 years into the study Over 280 endoscopists participating in the PPT carry out the T1 and T4 colonoscopies Although the recurrence of one or more adenomas is the primary endpoint of the study it will also be possible to relate the dietary intervention to number size and histotype of polyps Because some polyps 10-15 tend to be missed at baseline the primary analytic interval on which sample size calculations were based is T1 through T4
The presence of one or more adenomas at the qualifying colonoscopy--a key eligibility factor for PPT--was determined by Clinical Center trial pathologists who had been previously oriented by the central pathologists to PPT pathologic criteria The number size and location of adenomas at baseline was determined by the participating endoscopists To standardize the histologic diagnoses used in endpoint ascertainment the PPT requires that histologic type and extent of atypia be determined by the central pathologists for all lesions removed at baseline T1 and T4
Blood specimens are collected on all participants annually these are analyzed on a 20 participant sample the same individuals for whom the diet records are analyzed for lipids carotenoids and vitamins A and E Blood specimens are also available for other analyses including hormone and molecular genetic analysis
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None
Secondary IDs
| Secondary ID | Type | Domain | Link |
|---|---|---|---|
| OH91-C-0159 | None | None | None |