More than half of premenopausal breast cancer survivors gain weight during the first postsurgical year. A greater than average weight gain has been associated with an increased risk for breast cancer recurrence weight gain during menopause is greatest during its first decade.and death. Adult weight gain also increases the risk of postmenopausal breast cancer. It is estimated that weight gain during menopause is greatest during its first decade. There is increasing evidence that elevated plasma free estradiol, the portion of estradiol not bound to plasma proteins, is associated with both weight gain and an increased risk for breast cancer. There has been very limited research on whether free estradiol can be modulated through dietary or body fat changes. Therefore, we will also evaluate in this protocol the impact that a reduction in dietary fat, an increase in dietary fiber, weight loss and a change in body fat percentage or body fat distribution has on plasma free estradiol.
The aims of this pilot study are to conduct a randomized controlled clinical trial with 72 breast cancer survivors (36 to the intervention group and 36 to the control group). The sample will be stratified evenly between pre/peri menopausal and post-menopausal subjects. Participants in the intervention group will be offered 13 nutrition education sessions. The goals of the nutrition intervention are to help paritipants: a) Reduce fat intake to 15% of calories (with the calorie level set to maintain or achieve a healthy weight); b) Increase fiber intake to 40 grams per day by consuming a diet rich in fruits, vegetables and unprocessed complex carbohydrates and c) Establishing or maintaining an exercise pattern of at at least 1000 kilocalories/week. The primary hypothesis is that the intervention group will have a significantly greater reduction in the percentage of plasma free estradiol than the control group. A secondary hypothesis is that the intervention group will have significantly fewer women than the control group who have a net weight gain since breast cancer surgery of five or more pounds. Other variables of interest are whether the intervention results in changes in the body fat percentage, the ratio of upper to lower body fat, and in the lipid profile. We will also assess whether the intervention hormonal patterns differently between pre, peri and postmenopausal women. Additionally, we will compare the effect of the dietary intervention on the percentage of plasma free estradiol to another potential biomarker for breast cancer risk, the ratio of 2-hydroxyestrone to 16-alpha-hydroxyestrone. Secondary questions include how changes in dietary intake, physical activity, and weight-related parameters are related to the quality of life, perception of risk from breast cancer, and participants' satisfaction with the protocol.
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