The Effects of Concurrent Training on Molecular, Functional, and Clinical Outcomes in Breast Cancer Survivors: A Pilot Study

<b>Background</b>: Breast cancer survivors (BCS) experience long-term adverse effects, with breast cancer-related lymphedema (BCRL) being one of the most common complications. Exercise is suggested as a safe strategy to improve functionality in BCS with or at risk of developing BCRL. However, the effects of concurrent training in these patients are poorly understood. The aim of the study was to analyze the effects of a 12-week supervised concurrent training program and a 12-week follow-up period without training on molecular, functional, and clinical outcomes in BCS. <b>Methods</b>: A single-arm study was conducted in 11 BCS with or at risk of BCRL to analyze the effects of a 12-week concurrent training and a 12-week follow-up period on molecular (92 inflammation-related proteins), functional (upper- and lower-body strength, handgrip strength, and cardiorespiratory fitness), and clinical (body mass index, arm volume, subcutaneous and muscle thickness, range of motion, physical activity levels and heart rate variability, pain, and quality of life [QoL]) outcomes. <b>Results</b>: The 12-week concurrent training program significantly improved upper-body muscle strength, handgrip strength, pain, emotional well-being, and total QoL. In addition, after the 12-week follow-up period, the increase in row strength was maintained, and a significant decrease in various inflammation-related proteins was observed. <b>Conclusions</b>: A 12-week concurrent training program improved strength, pain, and QoL in BCS without increasing inflammation. After the follow-up period, inflammation-related protein levels decreased, and row strength gains were maintained, supporting the potential effects of concurrent training. Further larger and controlled studies are needed to confirm the results.