Efficacy and toxicity of reirradiation using Intensity Modulated Radiotherapy for recurrent or second primary nasopharyngeal carcinoma

Abstract

PURPOSE/OBJECTIVE(S): Patients with recurrent or second primary nasopharyngeal carcinoma (NPC) have a poor prognosis due to limited therapeutic options. External beam reirradiation is often used, but it is difficult to retreat the target to high dose due to reduced therapeutic ratio. Intensity-modulated radiotherapy (IMRT) is a highly conformal technique that may improve treatment outcome when used for reirradiation of head and neck cancers. This study reported our experience in using IMRT-based salvage regimen for recurrent or second primary NPC. MATERIALS/METHODS: This was a retrospective study of patients treated by IMRT for recurrent or second primary NPC at Queen Mary Hospital and Hong Kong Sanatorium & Hospital. Only patients with loco-regional disease were included in the report. The primary endpoint was overall survival (OS), and secondary endpoints were loco-regional control (LRC) rate, local control (LC) rate and late toxicity. RESULTS: Fifty patients were treated using step-and-shoot IMRT (n:46) or helical tomotherapy (n:4) from December 2000 to March 2010. Thirty-nine patients (78%) also received platinum-based induction chemotherapy prior to reirradiation, 19 patients (38%) received cetuximab concurrently with reirradiation, and 10 patients (20%) received stereotactic radiosurgery boost after reirradiation. The median radiation dose was 56Gy. The median follow-up for censored subjects was 47 months. The 3-year actuarial OS and LRC rates were 47.4% and 43.4%, respectively. Patients treated for rT4 disease had a significantly worse tumor control than those treated for rT1 - 3 disease, the corresponding 3-year LC rates were 29.8% and 61.8% (p = 0.037). Approximately 48% of patients had late toxicity following treatment, and 12% had at least one grade 3 late toxicity. Two treatment-related deaths were observed, both due to severe hemorrhage secondary to carotid pseudoaneurysm. CONCLUSIONS: Aggressive IMRT-based salvage regimen was found to be feasible and resulted in relatively good tumor control and survival outcome in retreatment of NPC. Late toxicities were common, but severe toxicities appeared to be less common then other series describing reirradiation using non-IMRT approach. Copyright © 2011 Published by Elsevier Inc.