Abstract Background: Breast cancer in women over 65 years old is set to increase by 50% over the coming decades. Despite favorable tumor profiles, older women with breast cancer fare worse than younger patients. Age-related declines in functional status, comorbidities, malnutrition, and sarcopenia exacerbate treatment toxicity, contributing to poorer outcomes and lower received dose intensity (RDI). RDI reflects both chemotherapy dose and timing of treatment administration. A RDI below 85% raises recurrence and mortality risk 1.5 to 3-fold. Exercise and higher protein diet interventions targeting physical function may enhance RDI and survival in this vulnerable population. Methods: The TeleHealth Resistance Exercise Intervention to Preserve Dose Intensity and Vitality in Elder Breast Cancer Patients (THRIVE-65) trial is a Phase II randomized controlled trial evaluating a multicomponent resistance and aerobic exercise intervention with protein intake support versus Health Education and Support (HES) control group on RDI (primary aim) in 270 older women with breast cancer while actively undergoing neo/adjuvant chemotherapy. Secondary outcomes include chemotoxicities; physical function, psychological, psychosocial status (via comprehensive geriatric assessment); quality of life, fatigue, sleep; health care utilization; physical activity behaviors; dietary intake; strength; body composition; and treatment dose delays, reductions early termination. We will also explore intervention implementation barriers and facilitators. Eligibility criteria are women age ≥65 with stage I-III invasive breast cancer, 18-50 kg/m2 BMI, starting at least 10 weeks of neo/adjuvant cytotoxic chemotherapy for curative intent, able to walk for 6 minutes and/or 2 blocks, no current exercise training, no therapeutic diet/weight-loss medication, and English speaking. The HES group receives a tablet with supportive programming (e.g., meditation, yoga, non-tailored nutrition programs) and Fitbit. The virtually-delivered THRIVE-65 intervention includes twice-weekly supervised resistance exercise, 90 minutes/week of unsupervised aerobic exercise, and diet counseling aimed to achieve a protein intake of 1.2 g/kg/day, led by trained exercise physiologist and registered dietitian from a central call center, as well as the HES group tablet and Fitbit. Measurements include anthropometrics, questionnaires, comprehensive geriatric assessment, body composition and objectively measured physical activity. The primary analysis assumes 65-75% of the HES group will achieve an RDI of 85% and hypothesizes that 82-89% of the THRIVE-65 intervention will achieve an RDI of 85% (80% power, two-sided 0.05 significance level). To date, 115 women have been randomized across 3 US medical centers. Support: U01CA271277-03, T32CA186873-11 Clinicaltrials.gov identifier: NCT05535192 Citation Format: E. Schleicher, J. Oppenheim, W. Kemp, S. Doerksen, K. Diguglielmo, S. M. Garrett, M. Ahmed, J. Binder, T. L. Nguyen, C. Mills, A. Tanasijevic, C. Owsusu, C. Thomson, K. Basen-Engquist, J. A. Ligibel, K. Schmitz. The TeleHealth Resistance Exercise Intervention to Preserve Dose Intensity and Vitality in Elder Breast Cancer Patients (THRIVE-65) Trial abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-09-01.
Schleicher et al. (Tue,) studied this question.