A randomized trial of the effect of a plant-based dietary pattern on additional breast cancer events and survival: the Women’s Healthy Eating and Living (WHEL) study

The Women's Healthy Eating and Living (WHEL) Study is a multisite randomized controlled trial of the effectiveness of a high-vegetable, low-fat diet, aimed at markedly raising circulating carotenoid concentrations from food sources, in reducing additional breast cancer events and early death in women with early-stage invasive breast cancer (within 4 years of diagnosis). The study randomly assigned 3088 such women to an intensive diet intervention or to a comparison group between 1995 and 2000 and is expected to follow them through 2006. Two thirds of these women were under 55 years of age at randomization. This research study has a coordinating center and seven clinical sites. Randomization was stratified by age, stage of tumor and clinical site. A comprehensive intervention program that includes intensive telephone counseling, cooking classes and print materials helps shift the dietary pattern of women in the intervention. Through an innovative telephone counseling program, dietary counselors encourage women in the intervention group to meet the following daily behavioral targets: five vegetable servings, 16 ounces of vegetable juice, three fruit servings, 30 g of fiber and 15-20% energy from fat. Adherence assessments occur at baseline, 6, 12, 24 or 36, 48 and 72 months. These assessments can include dietary intake (repeated 24-hour dietary recalls and food frequency questionnaire), circulating carotenoid concentrations, physical measures and questionnaires about health symptoms, quality of life, personal habits and lifestyle patterns. Outcome assessments are completed by telephone interview every 6 months with medical record verification. We will assess evidence of effectiveness by the length of the breast cancer event-free interval, as well as by overall survival separately in all the women in the study as well as specifically in women under and over the age of 55 years.