Lifestyle Program for Breast Cancer Improves Body Composition, Fitness, and Patient-Reported Outcomes: A Randomized...

Importance: Lifestyle and supportive care interventions may improve treatment tolerance, long-term health behaviors, and survivorship outcomes among breast cancer patients receiving radiotherapy. Few randomized trials have integrated nutrition, exercise, stress management, and psychosocial counseling concurrently with radiotherapy and extended across survivorship. Objective: To evaluate the effects of a comprehensive lifestyle intervention (CompLife) initiated during radiotherapy and maintained for 12 months on body composition, fitness, quality of life, symptoms, and nutrition. Design, Setting, and Participants: Randomized clinical trial at a single cancer center. Eligible women were aged ≥18 years with stage II/III breast cancer scheduled for radiotherapy, BMI ≥ 24.5, and ≥2 lifestyle risk factors. Participants were randomized to CompLife or standard of care (SOC). Assessments occurred at baseline, end of radiotherapy, and 3, 6, and 12 months. The primary outcome of recurrence is ongoing; this report examines prespecified secondary outcomes. Interventions: CompLife included 6 weeks of in-person counseling integrating nutrition, physical activity, mindfulness, stress management, and psychosocial support; twice-weekly exercise, diet, and mind-body sessions during radiotherapy; and telehealth counseling for 12 months. SOC participants received standard educational materials. Main Outcomes and Measures: Secondary outcomes included visceral adipose tissue (VAT), weight, waist circumference, fitness (VO₂ max, strength), SF-36 Physical and Mental Component Summary scores, MD Anderson Symptom Inventory scores, mindfulness (FFMQ), and dietary fiber intake. Results: Ninety-five women were randomized (CompLife, n = 50; SOC, n = 45). CompLife participants had lower VAT at 3 and 6 months (e.g., 3 months: 118 vs. 141 cm²; p = 0.044) and greater improvements in VO₂ max at 3 (23.4 vs. 18.8 mL/kg/min; p = 0.025) and 6 months. SF-36 Physical scores improved to within population norms for CompLife at all follow-ups but remained below norms in SOC. CompLife participants reported fewer symptoms at 12 months (MDASI: 1.3 vs. 2.5; p = 0.014). Fiber intake was consistently higher in CompLife participants (20.5 g vs. 14.0 g; p < 0.001). The results should be interpreted with caution due to the large number of comparisons among the secondary outcomes. Conclusions and Relevance: A multidisciplinary lifestyle intervention delivered during radiotherapy and extended across survivorship produced clinically meaningful improvements in body composition, fitness, diet, and patient-reported outcomes. The findings suggest potential value in integrating structured lifestyle and psychosocial counseling into oncology care and warrant confirmation in larger multicenter trials with mature recurrence endpoints.