Radiation Therapy of Brachial Plexus Syndrome from Breast Cancer

Abstract

Brachial plexus syndrome occurs not infrequently in patients with malignant disease. It is due to compression or direct invasion of the nerves by tumor, causing pain and sensory and motor deficits of the upper extremity. Since little can be found in the literature on the treatment of the syndrome, this study reports an evaluation of the effects of radiation therapy in 47 cases of brachial plexus syndrome secondary to metastatic mammary cancer. The brachial plexus is formed by the union of the anterior branches of the lower four cervical nerves and the first dorsal nerve. It supplies the whole upper extremity and the shoulder girdle. The plexus lies in the posterior cervical triangle covered by skin, platysma, and deep fascia and emerges between the scalenus medius and anticus (Fig. 1) (1). It then passes behind the clavicle, following the course of the subclavian vessels. In the second part of the axilla, the cords surround the artery on three sides. Involvement of the plexus by mammary carcinoma is usually due to bulky metastatic lymph nodes in the supraclavicular and/or axillary areas. Occasionally, extensive subcutaneous metastases in the supraclavicular and axillary areas may also impinge on or invade the nerves of the plexus. The symptoms and signs encountered in the upper extremity may include pain and swelling, sensory loss, muscular weakness or paralysis, vasomotor and trophic disturbances. Muscle atrophy and contractures are not infrequent, especially when the muscular paralysis is of long duration. Pain is apt to be very severe, requiring progressively increasing dosage of analgesics, only to become eventually unresponsive. The extent of edema in the upper extremity depends upon the degree of associated vascular and lymphatic obstruction. Sensory deficits may include various degrees or combinations of paresthesias, numbness, and hypalgesia. Motor deficits vary from the early signs of muscular weakness progressing to paralysis and, eventually, atrophy and contractures. The skin becomes atrophic and glistening, particularly over the fingers and dorsum of the hand. Material This study includes the analysis of the results of radiation treatment of 47 patients who had brachial plexus syndrome from metastatic mammary cancer. All had, in addition to pain, varying degrees of sensory and motor disturbances in the upper extremity. There were bulky and often matted fixed lymph nodes in the supraclavicular or axillary regions. Positive histological diagnosis was obtained in each instance. Patients with pain only and without sensory or motor deficits were excluded from this study. Almost all cases were evaluated by a neurologist. In a few instances electromyography, oscillometric readings, and brachial arteriography were also carried out. Of the 47 patients, 33 were originally classified as operable, and mastectomies, with and without postoperative radiation, had been performed.