LINAC-based fractionated stereotactic radiotherapy for residual and recurrent nasopharyngeal carcinoma in the era of intensity-modulated radiotherapy: A 10-year Experience

Abstract

Introduction: We reviewed the use of frameless linear accelerator-based fractionated stereotactic radiotherapy (FSRT) in a single centre as salvage treatment for patients with nasopharyngeal carcinoma with local failure. Methods: We retrospectively reviewed the data of all patients with residual or recurrent nasopharyngeal carcinoma who had undergone salvage therapy with FSRT at our institution between 2008 and 2017. Survival data were analysed by the Kaplan-Meier method. Univariate analyses for survival outcomes were performed using the Cox proportional hazards model. Severe late radiation toxicities were assessed. Results: Of the 49 patients included, 44 (90%) had previously received intensity-modulated radiotherapy as primary treatment. The median FSRT dose was 18 Gy in three fractions for residual disease, and 48 Gy in six fractions for recurrent disease. Median follow-up was 41.1 months. The 3-year local control rate, progression-free survival (PFS), disease-specific survival, and overall survival (OS) for patients with residual disease (n = 34) were 78.9%, 66.2%, 82.2%, and 74.0%, respectively. Those for patients with recurrent disease (n = 15) were 68.2%, 40.0%, 58.7%, and 46.7%, respectively. Using FSRT, a gross tumour volume of ≤16 mL of residual disease was associated with longer PFS and OS. N3 nodal staging status was associated with poorer PFS in the residual disease group. Severe late complications occurred in 12 patients (24%), including one patient from the residual disease group and four patients from the recurrent disease group with fatal haemorrhage (10%). Conclusion: Using this less-invasive and resource-friendly technique, the clinical outcomes from our centre were comparable to those in the literature.