Randomized trial of diet and exercise on chemotherapy completion in women with breast cancer: The Lifestyle, Exercise, and Nutrition Early After Diagnosis (LEANer) study.
Authors: Sanft Tara B. , Harrigan Maura , Cartmel Brenda , Li Fangyong , Zupa Michelle , McGowan Courtney , Ferrucci Leah M. , Puklin Leah , Nguyen Thai Hien , Tanasijevic Anna , Neuhouser Marian L. , Hershman Dawn L. , Basen-Engquist Karen , Jones Beth A. , Knobf M. Tish , Chagpar Anees B. , Silber Andrea , Ligibel Jennifer A. , Irwin Melinda L. 
Published: June 2022

12007 Background: In observational studies, 25%-55% of women with breast cancer (BC) do not complete chemotherapy as initially prescribed, primarily due to toxicity. Relative dose intensity (RDI) is an integrated measure of chemotherapy dose delays and reductions and is associated with cancer mortality. Physical activity (PA) and diet may reduce treatment toxicity, but less is known about their effect on RDI. We conducted a randomized trial of a diet and PA intervention on RDI (primary endpoint) in women with newly diagnosed BC initiating chemotherapy. Methods: 173 women with Stage I-III BC were randomized to usual care (UC, n = 86) or a yearlong, 16-session, in-person or telephone-administered diet and PA intervention (n = 87) delivered by registered dietitians. Dates, doses and reason for dose-adjustments/delays of chemotherapy were abstracted from electronic medical records or obtained from treating oncologists. T-tests and Chi-square tests were used to examine the effect of the intervention vs. UC on RDI. Results: Participants were 53±11 years old, had a body mass index of 29.7+6.8 kg/m2, 51% had stage I BC and 22% were under-represented minorities. 27 different chemotherapy regimens were prescribed. Participants randomized to intervention completed 94% of counseling sessions during chemotherapy and had statistically significant improvements in PA and diet compared to UC. Average continuous RDI was unexpectedly high in both groups, with 93%+14% of prescribed chemotherapy completed (p = 0.92). However, 17% and 15% of intervention and UC participants, respectively, had < 85% RDI (p = 0.70) and more than one-third had at least one toxicity-associated dose reduction and/or delay (> 7 days) for at least one chemotherapy drug (39% intervention and 37% UC, p = 0.80). In posthoc analyses, there was a benefit of the intervention on chemotherapy completion compared to UC in the 74 women receiving neoadjuvant chemotherapy (RDI: 95% intervention vs. 90% UC, p = 0.05). Among intervention women, a dose-response effect was seen with participants who achieved more PA and better diet quality via the Healthy Eating Index (above median) experiencing higher RDI vs participants who were below the median for PA and/or diet quality (97% vs 90% RDI, p = 0.05). Conclusions: A primarily telephone-based diet and PA intervention led to improved diet and PA, but did not improve RDI compared to UC. However, a dose-response effect of the intervention was observed with higher PA and diet associated with higher RDI. Future analyses will examine intervention effects on secondary endpoints of endocrine therapy adherence and patient-reported outcomes when all women reach the 1-year timepoint (end of intervention). Further study of diet and PA interventions in patients receiving neoadjuvant chemotherapy are necessary. Clinical trial information: NCT03314688.