Effects of presurgical HIIT in hormone receptor-positive, HER 2-negative breast cancer cases: Two case reports from the GEICAM EFiK study.

The purpose of this study was to determine the effects of a high-intensity interval-training (HIIT) or stretching-balance intervention 3 weeks prior to surgery in two hormone receptor-positive and human-epidermal growth-factor receptor 2-negative breast cancer patients. Patient 1 (58 years, stage IIA ductal carcinoma) performed a preoperative exercise program, and Patient 2 (63 years, stage IIB ductal carcinoma) underwent stretching-balance intervention. Tumor Ki67, body composition, oxygen uptake, inflammatory biomarkers, and psychological variables were measured before the intervention (T1), and prior to tumor resection (T2). Ki67 remained unchanged in Patient 2 and decreased by 28.6% in Patient 1. Patient 1 maintained her body mass (BM) and body mass index (BMI) with minor variation, while Patient 2 slightly increased her BM and BMI. Both patients increased their fat mass (FM) and %FM and decreased lean body mass (LBM) and %LBM, although to different extents. Peak oxygen uptake increased in Patient 1 and decreased in Patient 2. Interleukin-6 decreased, and C-reactive protein increased in both patients. Patient 1 showed a reduction in depressive symptoms, while Patient 2 exhibited no changes. Based on this case report, presurgical HIIT intervention appears to be a more promising exercise approach. However, larger scale-controlled studies will be needed.