Electromyography in the estimation of nerve lesions after surgical and radiation therapy for breast cancer.

EMG was performed on the upper extremity of the affected side in 55 breast cancer patients who had undergone mastectomy and postoperative radiotherapy. Radical mastectomy caused six latissimus pareses out of 26 patients and seven deltoideus pareses out of 49 patients. Simple mastectomy caused no pareses. As an early complication of radiotherapy five out of 16 patients developed slight EMG changes, most often in the biceps brachii muscle, but no clinical pareses were observed. In the follow-up group (at least 5 years after primary treatment) 18 out of 25 patients had varying EMG alterations. The relative frequency of EMG findings indicates an increasing number of neural changes caused by radiotherapy in the follow-up group. Severe pareses were infrequent as complications of radiotherapy. In neurography of the cutaneous branch of n. radialis a diminution of the amplitude of the sensory response was found one or two months after radiotherapy in the affected side. EMG proved to be useful in estimating both the early and late neural complications of primary treatment of breast cancer and in evaluating patients' capacity for work.