Changes in pectoralis major stiffness and thickness following radiotherapy for breast cancer: A 12-month follow-up case series

Radiotherapy (RT) is a common and often essential treatment for breast cancer, but has been associated with pectoralis major (PM) muscle fibrosis and atrophy. In an initial prospective evaluation, we assessed muscle stiffness and muscle thickness of the sternocostal and clavicular regions of the PM with ultra -sound shear wave elastography and B-mode imaging. Changes in PM muscle stiffness and thickness fol-lowing RT can be detected within the first twelve months of RT completion. These parameters may potentially be useful for screening of patients who would benefit from post-RT physical therapy. Further studies with larger sample sizes that include patients who receive nodal radiation are necessary to confirm these findings.(c) 2022 Elsevier B.V. All rights reserved. Radiotherapy and Oncology xxx (2023) xxx-xxx

Automated summary

Radiotherapy is commonly used in breast cancer treatment, but it can lead to fibrosis and atrophy of the pectoralis major muscle. This study used ultrasound shear wave elastography and B-mode imaging to assess muscle stiffness and thickness of the pectoralis major muscle after radiotherapy. Changes in muscle stiffness and thickness were detected within the first twelve months after radiotherapy, suggesting that these parameters could be used to identify patients who would benefit from post-radiotherapy physical therapy. Further studies with larger sample sizes and patients receiving nodal radiation are needed to confirm these findings.