Diet and Breast Cancer Prevention Trial
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Study type: Interventional
Phase: Phase 3

Summary: 
      This randomized controlled trial tests the hypothesis that a reduction in intake of dietary
      fat will reduce the incidence of breast cancer. Women with more than 50% of the breast
      occupied by dense tissue on a mammogram have been recruited and allocated by a random (ie
      chance) process, to an intervention or control group. The intervention group has been taught
      how to reduce their fat intake to a target of 15% of total calories, while the control group
      continued their usual consumption of fat. Both groups have then been followed for at least 7
      years and the number who develop breast cancer in each group will be compared
    

Detailed description: 
      The long term goal of this trial is to determine if intervention in subjects with extensive
      mammographic densities (a risk factor for breast cancer) with a low fat-high carbohydrate
      diet will reduce the incidence of breast cancer by 37%. We propose to meet this goal by
      carrying out a randomized multi-centre trial of dietary intervention in subjects at increased
      risk of breast cancer that is now in progress.

      The method used is to recruit subjects with extensive mammographic densities and enrol them
      in a randomized trial in which they receive one of two kinds of dietary counselling. A
      control group receives general advice about nutrition but is not counselled to change their
      intake of dietary fat or carbohydrate, and an intervention group is given intensive
      counselling to reduce their intake of total fat to a target of 15% of calories and increase
      intake of carbohydrate to maintain intake of total calories.

      Recruitment to this trial has been in progress in Toronto, Hamilton, London and Windsor since
      1991, and in Vancouver since 1994, and all of the 4,615 subjects required for the trial were
      recruited by November 1998.

      The trial is explanatory in that it seeks to determine if there is a biological effect of
      dietary fat reduction in terms of a reduction in breast cancer incidence. To meet this goal
      we will select as participants highly motivated subjects who are at increased risk of breast
      cancer, provide them with a high level of assistance in making a dietary alteration, follow
      them carefully to ensure the correct identification of subjects who develop breast cancer,
      and analyse the results both according to intention to treat and dietary compliance. This
      trial does not attempt to assess directly the possible effects of dietary counselling on the
      health of the general public.

      II Specific Aims

        1. To recruit 4,615 Canadian women with extensive mammographic density and to enrol them in
           a randomized trial of dietary fat reduction and follow up until 2006.

        2. To compare in the control and intervention groups of this trial the incidence of breast
           cancers, as well as other histological changes in the breast tissue of patients
           undergoing surgical biopsy of the breast.

        3. To determine if a reduction in dietary fat intake will reduce either the proportion of
           the breast area occupied by radiological signs of density or the total quantity of
           density.
    

Intervention name(s): Low-fat diet
Intervention type(s): Behavioral
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Diet; Dietary fat; Breast cancer; Prevention