Preliminary study of intensity-modulated carbon ion reirradiation for locoregionally recurrent nasopharyngeal carcinoma after definitive IMRT——Clinical experience from Shanghai Proton Heavy Ion Hospital / 中华放射肿瘤学杂志

ABSTRACT

Objective To evaluate the short-term efficacy and toxicities of intensity-modulated carbon ion radiotherapy (IMCT) for patients with locoregionally recurrent nasopharyngeal carcinoma after intensity-modulated radiotherapy (IMRT).Methods A total of 112 patients with locoregionally recurrent nasopharyngeal carcinoma undergoing salvaging IMCT between May 2015 and February 2018were enrolled in the study.All patients previously received one course of definitive X-ray IMRT.Among them,10 patients (9％) were diagnosed with stage Ⅰ,26 patients (23％) with stage Ⅱ,41 patients (37％) with stage Ⅲ and 35 patients (31％) with stage Ⅳnasopharyngeal carcinoma,respectively.The median age of the cohort was 48 years (range,17-70 years) old.The median dose to the gross tumor volume (GTV) was 60 GyE (range,50-69 GyE).Results With a median follow-up time of 20 months (range,5-45 months),20 patients died and 42 patients developed local recurrence.The 2-year overall survival (OS) and local progression-free survival (LPFS) rates were 85％ and 52％.Both univariate and multivariate analyses demonstrated that stage Ⅳ disease was associated with significantly worse OS.No predictors were found for LPFS.No acute toxicity of grade 3 or higher was observed during reirradiation.Severe (grade 3 or above) late toxicities included xerostomia (n =1),hearing impairment (n =2),temporal lobe injury (n =1) and mucosal necrosis (n =19).Conclusions IMCT is an efficacious and safe treatment for patients with locoregionally recurrent nasopharyngeal carcinoma with acceptable toxicity profile.Long-term follow-up is necessary to further evaluate the long-term efficacy and late toxicities.