Clinical outcomes after local field conformal reirradiation of patients with retropharyngeal nodal metastasis

BACKGROUND: The purpose of this study was to present our experience with retropharyngeal node reirradiation using highly conformal radiotherapy (RT). METHODS: A retrospective screen of 2504 consecutively irradiated patients with head and neck malignancies between 2005 and 2015 identified 19 patients who underwent reirradiation for retropharyngeal node metastasis. Clinical and toxicity outcomes were assessed in these patients. RESULTS: Thirteen patients (68%) had squamous cell carcinoma. Eleven patients (58%) received conventionally fractionated intensity-modulated radiotherapy (IMRT) or proton therapy, and 8 patients (42%) received single-fractionated or hypofractionated stereotactic RT. Fourteen patients (74%) received chemotherapy. Median follow-up was 14.7 months. The 1-year local control, locoregional control, overall survival, and progression-free survival rates were 100%, 94%, 92%, and 92%, respectively. Three patients (16%) experienced acute grade 3 toxicity and occurred in those treated with IMRT. There was no late grade ≥3 toxicity. CONCLUSION: Retropharyngeal node reirradiation with conformal therapy is well tolerated and associated with excellent short-term disease control.