Intensity-modulated radiation therapy for T4 nasopharyngeal carcinoma. Treatment results and locoregional recurrence.

PURPOSE: The purpose of this work was to examine outcomes in patients with T4 nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). METHODS AND MATERIALS: Between 2007 and 2010, 154 patients with nonmetastatic T4 NPC were treated with IMRT to a total dose of 70 Gy in 33-35 fractions. In addition, 97% of patients received concurrent platinum-based chemotherapy. The median follow-up time was 52.8 months. RESULTS: The rates of 5-year actuarial locoregional control, distant metastasis-free survival, progression free-survival, and overall survival (OS) were 81.2, 72.2, 61.9, and 78.1%, respectively. A total of 27 patients had locoregional recurrence: 85.2% in-field failures, 11.1% marginal failures, and 3.7% out-of-field failures. Fourteen patients with locoregional recurrence received aggressive treatments, including nasopharyngectomy, neck dissection, or re-irradiation, and the 5-year OS rate tended to be better (61.9%) compared to those receiving conservative treatment (32.0%, p=0.051). In patients treated with 1 course of radiotherapy, grade ≥3 toxicities of ototoxicity, neck fibrosis, xerostomia, epistaxis, and radiographic temporal lobe necrosis occurred in 18.2, 9.8, 6.3, 2.1, and 5.6% of patients, respectively. Increased ototoxicity, osteonecrosis, severe nasal bleeding, and temporal necrosis were observed in patients treated by re-irradiation. CONCLUSION: IMRT offers good locoregional control in patients with T4 NPC. For patients with locoregional recurrence after definitive radiotherapy, aggressive local treatment may be considered for a better outcome.