Breast cancer is the most common cancer in women. Both screening and treatment of breast cancer have improved significantly over the last few years, resulting in higher survival rates. To improve quality of life of survivors, many recent studies have focused on the complications related to breast cancer treatment. Among other aspects, quality of life is reduced by impairments of the upper limb (e.g. pain, impaired shoulder mobility, decreased strength, arm lymphedema).

In the acute treatment phase of the cancer, breast and axillary surgery and radiotherapy cause scar tissue formation, wound formation, fibrosis, and shortening of soft tissues (eg, pectoral muscles). Initially, this may lead to upper-limb impairments, such as local postoperative pain and a subsequent decrease in range of motion (ROM). In a further postoperative stage, adhesive capsulitis, myofascial dysfunctions, and/ or nerve dysfunctions can also cause pain and impaired shoulder mobility. Forward shoulder position, induced by the shortened pectoral muscles and narrowing of the subacromial space, may lead to rotator cuff diseases, which can be painful and may limit upper-limb movements as well.

Besides pain and impaired shoulder mobility, decreased strength of the upper limb may be present in the short term and long term. These impairments of the upper limb may all lead to difficulties in performing activities of daily living. Another possible provoking factor of pain and impaired shoulder mobility may be lymphovascular disorders (e.g. axillary web syndrome) and the development of lymphedema.