Long-term survival outcomes and adverse effects of nasopharyngeal carcinoma patients treated with IMRT in a non-endemic region: a population-based retrospective study

OBJECTIVES: To evaluate the long-term survival outcomes and adverse effects of intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) and to summarise the experiences of IMRT in NPC in the past few decades in non-endemic northwest China. DESIGN: A population-based retrospective study. SETTING: An experience of using IMRT in non-endemic region of China. PARTICIPANTS: The study included 792 newly diagnosed and non-metastatic NPC patients who received IMRT from January 2006 to September 2018 in Xijing Hospital. OUTCOME MEASURES: The survival outcomes, adverse effects and failure patterns were evaluated by univariate, multivariate and subgroup analyses. RESULTS: With a median follow-up time of 46.2 months, the 5-year local recurrence-free survival, regional recurrence-free survival, distant metastasis-free survival, disease-free survival (DFS) and overall survival (OS) rates were 90.8%, 97.0%, 82.8%, 69.6% and 78.0%, respectively. Multivariate analysis showed that age, N stage, clinical stage, pathological type and primary tumour volume of more than 23 cm(3) were the independent prognosis factors for DFS (all p<0.05); age, N stage, pathological type, cervical lymph node necrosis, and anaemia were significantly associated with OS (all p<0.05). The most common acute toxicities of IMRT were dermatitis, mucositis and dysphagia. Xerostomia and hearing impairment were the top two late toxicities. The main failure patterns were distant metastasis and local and/or regional relapses. CONCLUSIONS: Similar survival, toxicities and failure patterns have been observed in patients treated with IMRT in a non-endemic area of China when compared with that in endemic areas. Induction chemotherapy combined with concurrent chemoradiotherapy may benefit locally advanced NPC in non-endemic areas of China.