Grant Abstract: RCT of Plant-based Diet in Breast Cancer Recurrence

Grant Number: 5R01CA069375-07
PI Name: John Pierce
Project Title: RCT of Plant-based Diet in Breast Cancer Recurrence

Abstract: DESCRIPTION (PROVIDED BY APPLICANT): This proposal is to complete and close out the Women's Healthy Eating and Living (WHEL) Study, an ongoing multi-center (7 clinical sites) randomized controlled trial examining the hypothesis that a plant-based dietary pattern affects additional breast cancer events and mortality. The study has enrolled 3109 women who were within 4 years of a primary diagnosis of Stage I (>1 cm), Stage II and Stage IIIA breast cancer and who had completed standard therapy. The study uses a behavior-change- theory-driven comprehensive and tailored intervention to motivate intervention group participants to substantially increase daily consumption of vegetables fruit and fiber while reducing fat in a dietary pattern that should result in a large increase in circulating carotenoids. The study includes regular measures of self-reported dietary and supplement intake, personal habits, quality of life and health status along with recording of physical measures and the collection and storage of samples of plasma, serum, buffy coat and washed red blood cells. 10 tissue slides are stored from the original tumor. All participants are contacted every six months for a health status assessment and medical records are reviewed for all reported cancer events as well as deaths. All women who recur are encouraged to stay in the study with a flexible schedule for assessments to reduce participant burden. At year 4 of the study we assess the use of complementary and alternative medicine services. The study is currently meeting all of its goals. At baseline, each group reported consuming approximately three vegetable servings/day. At one year the reported daily vegetable/vegetable juice servings were 7.1 for the intervention vs. 3.1 for the control and, for those who had been at least 2 years in the study, daily vegetable servings were at 6.4 Intervention vs. 3.1 Control. The maintained change in circulating carotenoids is: a-carotene +89% Intervention -3% comparison; [3-carotene levels +57% Intervention in comparison with lutein +23% Intervention and +7% in the comparison group. The study will use an intent-to-treat analysis to assess whether the study intervention effected outcomes both for the overall study sample, as well as those under and over 55 years at randomization. For each analysis, there will identify between four options: the dietary pattern reduced recurrence and mortality; it reduced recurrence but not mortality; it did not reduce recurrence but reduced mortality and it had no effect on either recurrence or mortality. The study will also investigate relationships between different components of the dietary pattern, circulating carotenoids and study endpoints.

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