Radiation-induced brachial plexus injury after radiotherapy for nasopharyngeal carcinoma

Abstract

Objective: Radiation-induced brachial plexus injury is a devastating complication that occurs after radiotherapy in the vicinity of the brachial plexus. Nasopharyngeal carcinoma, the most common type of cancer in Guangdong Province, is primarily treated with radiotherapy with subsequent side effects. However, radiation-induced brachial plexus injury is rarely reported in nasopharyngeal carcinoma. To draw attention to this correlation, we analyzed the clinical characteristics including the imaging findings of 10 patients suffering from radiation-induced brachial plexus injury for nasopharyngeal carcinoma.

Methods: We considered the patients' medical histories, analyzed their clinical characteristics, and monitored the long-term efficacy of treatment.

Results: The total irradiation dose of the nasopharynx ranged from 66.6 to 74 Gy, and that of the supraclavicular fossa ranged from 60 to 70 Gy. The mean latency was 8.2 ± 5.5 years. Seven patients initially complained of bilateral weakness, and three patients complained of isolated pain. The injuries of eight patients reached Grade 3 or worse. Magnetic resonance imaging showed a low signal on T1-weighted images and a high signal on short tau inversion recovery sequences in all cases. Swollen nerve fibers were clearly displayed in magnetic resonance diffusion tensor imaging. Electromyography showed myokymia in three patients. With conservative therapy, only one patient was temporarily relieved of pain, while the conditions of others were not ameliorated.

Conclusions: Radiation-induced brachial plexus injury is a late but catastrophic complication in patients with nasopharyngeal carcinoma. Clinicians should be aware of radiation-induced brachial plexus injury when deciding on treatment and should give them regular follow-up post radiotherapy.

Keywords: MRI; electromyography; nasopharyngeal carcinoma; neurological manifestations; radiation-induced brachial plexus injury.