Body Composition and Pectoralis Major Muscle Evaluation in Women Undergoing Breast Cancer Surgery: A Longitudinal Preliminary Observational Study

Background: The aim of this observational preliminary study is to detect any changes in body mass, muscle strength and characteristics of the pectoralis major muscle in women who have undergone breast surgery treatments. Methods: Instrumental assessments, completed before surgery and after 60 and 120 days, included sonoelastography, dynamometric examination and surface electromyography (sEMG) of the pectoralis major muscle, hand grip test, body bioimpedance analysis; the DASH (Disability of the Arm, Shoulder and Hand) questionnaire and pain assessment using the NRS (Numerical Rating Scale). Results: An initial increase in weight and fat mass was observed, followed by a reduction related to the resumption of physical activity stimulated by physiotherapy and medical support. The IC (intracellular)/EC (extracellular) ratio showed an increase in extracellular fluids in the final phase, indicative of possible water retention and early oedema. Muscle strength and DASH scores showed a functional decline, which may be explained by reduced physical activity and the direct involvement of the pectoral muscle in surgical and radiotherapy procedures. Sonoelastography showed color variations suggestive of changes in tissue stiffness, useful for distinguishing between reinforcement processes and possible scarring. Conclusions: This multidimensional approach can be useful in the early monitoring of some tissue alterations (i.e., fat mass) as an aid to define personalized rehabilitation protocols for women who have undergone breast surgery.