Long-term outcomes and safety after reirradiation in locally recurrent nasopharyngeal carcinoma in anon-endemic area.

Abstract

To determine outcomes and toxicities after reirradiation for locally recurrent nasopharyngeal carcinoma (rNPC) and to apply aprognostic index in anon-endemic region. We retrospectively reported progression-free survival (PFS), overall survival (OS), and treatment-related toxicities in patients treated with curative intent for locally rNPC. We applied the prognostic model for OS and grade5 radiotherapy (RT)-related toxicities published by Li etal. and evaluated its prognostic accuracy by receiver operating characteristic (ROC) curve analysis. Between 2005 and 2018, 33patients were treated for rNPC in our institution. Median follow-up was 60months. The mean time to local recurrence was 75months. Six (18%) patients had apersistent grade3 toxicity from aprevious RT course. The median re-RT dose was 66 Gy. After re-RT, 13patients had local failure and 3patients had metastatic recurrence. Median PFS was 18months with a5-year PFS rate of 29%. Median OS was 35months with a5-year OS rate of 37%. Grade3 or higher toxicities rate was 74%. There were 21% grade5 toxicities. The median time to agrade5 toxicity was less than 6months following re-RT. The prognostic nomogram was not predictive for OS or grade5 toxicities. Reirradiation of rNPC is an effective treatment but is associated with ahigh rate of life-threatening toxicity. Stratification of patients based on their risk of developing severe toxicity is needed to select patients who will most likely benefit from re-RT.