Radiation-induced brachial plexopathy in patients with nasopharyngeal carcinoma: a retrospective study

Radiation-induced brachial plexopathy (RIBP) is one of the late complications in nasopharyngeal carcinoma (NPC) patients who received radiotherapy. We conducted a retrospective study to investigate its clinical characteristics and risk factors. Thirty-onepatients with RIBP after radiotherapy for NPC were enrolled. Clinical manifestations of RIBP, electrophysiologic data, magnetic resonance imaging (MRI), and the correlation between irradiation strategy and incidence of RIBP were evaluated. The mean latency at the onset of RIBP was 4.26 years. Of the symptoms, paraesthesia usually presented first (51.6%), followed by pain (22.6%) and weakness (22.6%). The major symptoms included paraesthesia (90.3%), pain (54.8%), weakness (48.4%), fasciculation (19.3%) and muscle atrophy (9.7%). Nerve conduction velocity (NCV) and electromyography (EMG) disclosed that pathological changes of brachial plexus involved predominantly in the upper and middle trunks in distribution. MRI of the brachial plexus showed hyper-intensity on T1, T2, post-contrast T1 and diffusion weighted whole body imaging with background body signal suppression (DWIBS) images in lower cervical nerves. Radiotherapy with Gross Tumor volume (GTVnd) and therapeutic dose (mean 66.8±2.8Gy) for patients with lower cervical lymph node metastasis was related to a significantly higher incidence of RIBP (P<0.001). Thus, RIBP is a severe and progressive complication of NPC after radiotherapy. The clinical symptoms are predominantly involved in upper and middle trunk of the brachial plexus in distribution. Lower cervical lymph node metastasis and corresponding radiotherapy might cause a significant increase of the RIBP incidence.