Objective: To assess bilateral alterations in the pectoralis major and latissimus dorsi muscles in women in the non-active phase of breast cancer, focusing on muscle and tendon thickness and strength using ultrasound and dynamometry. Method: An observational study included 15 women (mean age: 52.7 years) with non-active phase breast cancer. Bilateral ultrasound measurements assessed pectoralis major and latissimus dorsi muscle thickness and pectoralis major tendon thickness. Maximum muscle strength was measured with a digital dynamometer. The Wilcoxon signed-rank test analyzed differences between affected and unaffected sides. Results: No statistically significant differences were observed in the thickness of the pectoralis major and latissimus dorsi muscles or the pectoralis major tendon between the affected and unaffected sides. However, a significant reduction in the maximum strength of the pectoralis major muscle was identified on the affected side ( P = .003), while no significant differences were found in the strength of the latissimus dorsi muscle. Conclusions: Breast cancer treatment significantly reduces pectoralis major muscle strength without observable changes in muscle or tendon thickness. Findings highlight the need for targeted rehabilitation to improve strength posttreatment.
Bravo-Aguila et al. (Sat,) studied this question.