Breast Cancer and Exercise Trial in Alberta
Condition: Breast Neoplasms
MeSH terms: Breast Neoplasms
Study type: Interventional

Summary: 
      The Breast Cancer and Exercise Trial (BETA Trial) is a randomized controlled trial aimed at
      understanding what dose (or volume) of exercise will best reduce the risk for breast cancer,
      particularly among women who are between the ages of 50-74. The primary aim is to compare the
      effects of a high versus moderate volume exercise intervention on specific biological
      intermediate endpoints for breast cancer in a group of previously inactive postmenopausal
      women
    

Detailed description: 
      Overview The proposed project is an evolution from a previous randomized controlled
      intervention trial conducted by the applicants known as the Alberta Physical Activity and
      Breast Cancer Prevention (ALPHA) Trial that examined how a one-year aerobic exercise
      intervention, as compared to a usual sedentary lifestyle, influenced specific hypothesized
      biologic mechanisms in the association between physical activity and breast cancer risk. In
      the proposed project, we plan to extend this research to examine how a one-year high versus
      moderate volume aerobic exercise intervention influences established and novel biologic
      mechanisms thought to influence breast cancer risk. We are specifically interested in
      studying what dose of exercise is required to influence the biologic mechanisms involved in
      breast cancer etiology.

      Rationale and Significance Inadequate physical activity, high total caloric intake, and
      obesity, central adiposity and weight gain throughout lifetime are all clearly associated
      with increased postmenopausal breast cancer risk and are some of the few risk factors
      amenable to intervention. Over one third of breast cancer can be attributed to these three
      risk factors. The exact dose and type of physical activity required for breast cancer risk
      reduction, however, are unknown. No trials have been conducted that have systematically
      examined how different volumes of activity influence mechanisms in breast cancer etiology.

      Study Aims The primary aim is to compare the effects of a high versus moderate volume
      exercise intervention on specific hormonal and biological intermediate endpoints for breast
      cancer in a group of previously sedentary postmenopausal women. The primary objectives will
      examine the effects of the interventions on measures of adiposity, insulin resistance, sex
      hormone levels, markers of obesity and inflammation and serum vitamin D. The secondary aim is
      to evaluate the impact of the high versus moderate exercise interventions among
      postmenopausal, sedentary women on psychosocial factors. The secondary objectives will
      compare the effects of the exercise interventions on quality of life and perceived stress
      among the participants. Adherence to the exercise intervention at 12 and maintenance of
      exercise at 24 months will also be assessed.

      Research Plan A two-centered, two-armed randomized controlled trial is proposed. In total,
      330 postmenopausal, sedentary women aged 50-74 years will be recruited from the screening
      programs and through media campaigns. Strict eligibility criteria will be applied to ensure
      that women enrolled in the study can be expected to have a change in breast cancer risk over
      the one-year long intervention. Randomization will be stratified on centre (Calgary or
      Edmonton) and on body mass index (< or ≥27.5). The intervention arm will undertake aerobic
      exercise sessions of 300 mins/week for 12 months. The control arm will be asked to undertake
      150 mins/week for 12 months. Baseline and 12-month measurements of adiposity (done by
      computerized tomography and dual energy X-ray absorbitometry scans), fitness, diet, physical
      activity, quality of life and stress, determinants of exercise adherence and medical, health
      and demographic characteristics will be made. Bloods, drawn at baseline, six and 12 months,
      will be assayed to measure estrone, estradiol, testosterone, androstenedione, insulin,
      glucose, adiponectin, leptin, interleukin-6, tumour necrosing factor-alpha, C-reactive
      protein and serum hydroxyvitamin D. One year after completion of the study, maintenance of
      physical and dietary habits will be measured. Intent-to-treat analysis will be used with a
      Laird-Ware mixed effects model to compare the changes from the baseline to 12-month
      follow-up. These data will be of direct relevance for effectiveness trials of exercise and
      diet for breast cancer prevention and for refinement of physical activity guidelines.
    

Intervention name(s): Moderate Volume; High Volume
Intervention type(s): Other; Other
Intervention description(s): Moderate volume (150 minutes per week) aerobic exercise; Participate in one-year high volume (300 minutes per week)aerobic exercise.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Phase 3 - To compare the effects of a high versus moderate volume exercise intervention on specific biological intermediate endpoints for breast cancer in a group of previously inactive postmenopausal women.
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Prevention and control; Exercise; Sedentary lifestyle; Biological markers