Definition and Diagnosis

Although increasingly rare, radiation therapy involving the brachial plexus (e.g., radiation for breast cancer or lymph nodes near the shoulder and axilla) or the lumbosacral plexus (e.g. radiation for pelvic cancers) may cause damage to these nerves. Although the exact cause is uncertain, patients predominantly develop numbness, sometimes followed by weakness, in the involved extremity. This usually occurs months to years after radiation therapy. Recurrent cancer involving the nerves must be excluded with imaging. Electrical testing helps confirm this diagnosis.

Treatment Options

Operative photograph of radiation plexitis. Both normal healthy nerves, as well as red, scarred radiation damaged nerves are visualized.

Treatment is mostly supportive. Painful tingling may be helped with medication. Physical therapy often improves the situation. There is no medication available to stop or reverse the symptoms. Unfortunately, numbness and weakness, when constant, often does not improve. Surgery is of questionable benefit and should only be considering on an individual basis. Open nerve biopsy is occasionally indicated to differentiate radiation plexitis from small amounts of tumor growth on the nerves that is too small to be seen on MRI.