Abstract PD12-08: PD12-08 Randomized trial of exercise and nutrition on pathological complete response among women with breast cancer receiving neoadjuvant chemotherapy: the Lifestyle, Exercise and Nutrition Early after Diagnosis (LEANer) Study

Background: Neoadjuvant chemotherapy is available to women with locally advanced breast cancer where chemotherapy is given prior to surgery. By examining resected tissue following neoadjuvant chemotherapy pathological complete response (pCR) can be determined. pCR is a favorable prognostic factor associated with longer survival compared to residual disease after neoadjuvant chemotherapy. Physical activity and diet may improve some side effects during treatment, but less is known about their effect on chemotherapy completion and more specifically on pCR in the neoadjuvant setting. Utilizing data from a randomized trial of diet and physical activity with a primary endpoint of chemotherapy completion in women with newly diagnosed breast cancer initiating chemotherapy, we evaluated the effect of a lifestyle intervention on pCR among the subset of women in the trial who received neoadjuvant chemotherapy. Methods: The Lifestyle, Exercise and Nutrition Early after Diagnosis (LEANer) Study enrolled 173 women with Stage I-III breast cancer who were randomized to usual care (n = 86) or a yearlong, 16-session, in-person or telephone-administered diet and physical activity intervention (n = 87) delivered by registered dietitians. Among study participants, 73 women received neoadjuvant chemotherapy and of these, 72 (98.6%) had complete follow-up pCR data (intervention = 40; usual care = 32). pCR, dates, doses and reason for dose-adjustments/delays of chemotherapy were abstracted from electronic medical records and confirmed with treating oncologists. A Chi-square test was used to examine the effect of the intervention versus usual care on pCR. Results: The 72 women receiving neoadjuvant chemotherapy with complete follow-up pCR data in LEANer were 49.4±11.6 years old, had a body mass index of 30.0+6.7 kg/m2, and 37.0% and 49.3% had stage I or II breast cancer, respectively. Just over half (52.1%) of women had ER/PR positive cancers and 32.9% of tumors were HER2 positive, with no statistically significant differences in tumor type by study arm. 92.7% of the women randomized to intervention adhered to all of the counseling sessions during their neoadjuvant chemotherapy and had statistically significant improvements in mean physical activity (161 minute increase versus 40 minute increase, p-value = < 0.001) and fiber intake (0.21 gram/day increase versus -5.17 g/day decrease, p-value = 0.020), as well as median fruit and vegetable intake (0.6 serving/day increase versus -0.5 serving/day decrease, p-value = 0.041) compared to usual care. There was a benefit of the intervention on pCR compared to usual care (52.5% with pCR in the intervention arm versus 28.1% with pCR in the usual care arm, p-value = 0.037). The intervention effect on pCR did not appear to be impacted by chemotherapy completion (relative dose intensity of 92% in intervention versus 90% in usual care) or chemotherapy dose delays as these were similar in the two study arms. In mediation analyses, results suggested that the changes in physical activity mediated, at least partially, the intervention effect on pCR. Conclusions: A primarily telephone-based diet and physical activity intervention led to improved pCR compared to usual care among the subset of women with breast cancer in the LEANer Study who received neoadjuvant chemotherapy. As pCR is an important prognostic factor for breast cancer, additional lifestyle interventions focusing on the neoadjuvant treatment setting with pCR as the primary outcome are necessary to confirm the potential benefits of lifestyle changes on pCR. Citation Format: Leah Ferrucci, Tara B. Sanft, Maura Harrigan, Brenda Cartmel, Fangyong Li, Michelle Zupa, Courtney McGowan, Leah Puklin, Thai Hien Nguyen, Anna M. Tanasijevic, Marian L. Neuhouser, Dawn Hershman, Karen Basen-Engquist, Beth Jones, Tish Knobf, Anees B. Chagpar, Andrea L.M. Silber, Jennifer A. Ligibel, Melinda L. Irwin. PD12-08 Randomized trial of exercise and nutrition on pathological complete response among women with breast cancer receiving neoadjuvant chemotherapy: the Lifestyle, Exercise and Nutrition Early after Diagnosis (LEANer) Study [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 PD12-08.