Characteristics of metastatic brachial plexopathy in patients with breast cancer.

PURPOSE: Brachial plexopathy in cancer patients is a rare but significant complication that causes pain and disability of the upper extremities. Clinical features of breast cancer patients with metastatic brachial plexopathy (MBP) have not been studied. We aimed to investigate the characteristics of MBP in breast cancer patients. METHODS: We retrospectively reviewed medical records of patients with breast cancer with MBP who visited Asan Medical Center from 2000 to 2016; we enrolled 44 patients. We comprehensively reviewed the characteristics, range of metastatic lymph nodes, initial symptoms, location, and severity of brachial plexus injury by electrodiagnostic study, radiologic findings, and associated complications. RESULTS: The mean age of patients with MBP was 51.9 ± 9.3 years; 25% were diagnosed with stage IV breast cancer at initial diagnosis. Weakness was the most common initial symptom of MBP (52.3%). Most patients showed limitation of shoulder range of motion and pain; 66% of patients exhibited malignant lymphedema. Forty-one patients were evaluated by electromyography; upper nerve trunk involvement (22.0%) was more frequent than lower nerve trunk involvement (9.8%). Nineteen patients underwent brachial plexus MRI, and supraclavicular area (SCA) metastasis was most frequent (57.9%). Sixteen patients were examined by both brachial plexus MRI and electromyography; patients with SCA metastasis exhibited significantly more frequent malignant lymphedema (p = 0.019) and upper nerve trunk involvement (p = 0.035), compared with patients with non-SCA metastasis. CONCLUSIONS: Our study revealed clinical features of MBP in breast cancer patients. Additional diagnostic evaluation focused on metastasis or aggravated metastatic tumor is needed when breast cancer patients are diagnosed with brachial plexopathy.