Reducing joint pain associated with aromatase inhibitor therapy and improving medication adherence in older breast cancer survivors through exercise and education: main results from the REJOIN randomized controlled pilot trial

Introduction Aromatase inhibitors (AIs) reduce recurrence and mortality in hormone receptor-positive breast cancer; however, up to 70% of patients discontinue therapy early because of AI-associated arthralgia. Joint pain affects more than half of AI users and can be burdensome among breast cancer survivors. Exercise and education may reduce symptoms and improve adherence, but interventions tailored for older survivors remain limited. Materials and methods We evaluated REJOIN, a remotely delivered exercise and education intervention. In this pilot randomized controlled trial, 24 older breast cancer survivors receiving AI therapy were recruited from two cancer centers and randomized to REJOIN or enhanced standard care. The 16-week intervention included supervised resistance and aerobic exercise, education on AI-related side effects, and self-management strategies. Outcomes included joint pain measured by the Brief Pain Inventory and AI adherence measured by the Morisky-Levine-Green Medication Adherence Scale. Additional measures included accelerometer-assessed physical activity and a geriatric assessment. Results Participants ( n = 24) had a mean age of 71.4 years (range 60–88), and more than one-third resided in rural communities. Retention was 80% over 12 months. Comparing REJOIN with standard care, changes from baseline to 4 months were evaluated using Wilcoxon tests and Cohen's d effect sizes. REJOIN showed a moderate reduction in joint pain interference (d = −0.47, p = 0.43). Self-reported AI medication adherence was high at baseline in both groups, limiting the ability to detect meaningful improvement; however, adherence patterns over follow-up favored the intervention group. Feasibility benchmarks were met, including accrual of the target sample, retention of 80% at 12 months, and achievement of the prespecified exercise-adherence benchmark, with 12 of 13 intervention participants (94%) completing the required supervised exercise and coaching sessions. Discussion REJOIN was feasible, safe, and acceptable among breast cancer survivors receiving AI therapy. Its remote delivery and engagement of rural participants suggest potential for dissemination and support progression to a larger efficacy trial.