Abstract P4-07-31: A whole food, plant-based (WFPB) dietary intervention to improve cardiometabolic and cancer-related outcomes in women with breast cancer
Authors: Campbell Erin , Campbell Thomas , Culakova Eva , Wixom Nellie , Guido Joseph , Blanchard Lisa , Fetten James , Janelsins Michelle , Mustian Karen , Peppone Luke 
Published: March 2023

Background: With dramatically rising obesity rates in the US, obesity at breast cancer diagnosis is common; further compounding the problem is that breast cancer treatment often results in additional weight gain. Among women undergoing breast cancer treatment, both obesity at diagnosis and post-diagnosis weight gain are associated with increased all-cause mortality and increased breast cancer mortality. We tested a WFPB dietary intervention in metastatic breast cancer patients to improve cardiometabolic and cancer-related outcomes, as it has been shown to reduce weight and improves cardiometabolic health in overweight and obese individuals.

Methods: Women with stage 4 breast cancer receiving treatment were randomized 2:1 into 2 arms: 1) a WFPB diet (N=21) or 2) usual diet (N=11) for 8 weeks with assessments at baseline, 4, and 8 weeks. Our WFPB diet consisted of an ad libitum whole food, plant-based diet; 3 meals/day were provided to WFPB subjects, which included fruits, vegetables, whole grains, nuts and seeds, and excluded meat, dairy, eggs, and added oils/solid fats. WFPB subjects received weekly education regarding diet. Subjects in the usual care group were asked to continue their usual diet for the next 8 weeks. Outcomes include cardiometabolic risk factors, related sex hormones, and cancer progression markers. Effects of the WFPB diet on the outcomes were assessed by comparing marginal means by arm estimated at 8 weeks from the analysis of covariance model controlling for the baseline value.

Results: Of the 32 subjects randomized, 30 subjects (20 WFPB and 10 usual care) completed all 3 assessments. Reductions in weight, BMI, total cholesterol, and LDL cholesterol were statistically significant as well as clinically meaningful, both within the WFPB group and between the groups. In the WFPB group, subjects lost a mean of 6.2% of their body weight versus 0.7% body weight loss in the control group (p&lt; 0.01). LDL cholesterol was reduced by a mean of 20.0% in the WFPB subjects versus a 10.6% increase in control subjects (p&lt; 0.01). Reductions in insulin and HOMA-IR, a measure of insulin sensitivity, were statistically significant within the WFPB group and trended towards significance between the groups. Sex hormone binding globulin (SHBG) levels increased significantly both within the WFPB group and between groups. There was a significant decrease in both IGF-1 and free testosterone within the WFPB group from baseline to week 8.

Conclusions: Our WFPB intervention resulted in improvements in several cardiometabolic and hormonal markers. The intentional weight loss, which was clinically large given the duration of the trial, was accompanied by reduced cholesterol, insulin resistance, free testosterone, and IGF-1. Given the moderate to large effect sizes noted, further study is warranted to evaluate the sustainability of benefits over time and to assess their potential impact on cancer-related outcomes.

Table 1: Cardiometabolic and Cancer-Related Outcomes

Citation Format: Erin Campbell, Thomas Campbell, Eva Culakova, Nellie Wixom, Joseph Guido, Lisa Blanchard, James Fetten, Michelle Janelsins, Karen Mustian, Luke Peppone. A whole food, plant-based (WFPB) dietary intervention to improve cardiometabolic and cancer-related outcomes in women with breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-31.