Effect of adaptive replanning in patients with locally advanced nasopharyngeal carcinoma treated by intensity-modulated radiotherapy: a propensity score matched analysis

ABSTRACT

Purpose. Limited data have been published regarding the effect of adaptive radiotherapy (ART) on clinical outcome in patients with nasopharyngeal carcinoma (NPC). We compared the long-term outcomes in patients with locally advanced NPC treated by adaptive intensity-modulated radiotherapy (IMRT) replanning versus IMRT. Methods. 200 NPC patients with stage T3/T4 were included between October 2004 and November 2010. Patients in both treatment groups were matched using propensity score matching method at the ratio of 11. Clinical outcomes were analyzed with Kaplan-Meier method, log-rank test and Cox regression. Results. After matching, 132 patients (66 patients in each group) were included for analysis. The median follow-up for the IMRT replanning group was 70 months, while the IMRT group was 69 months. The 5-year local-regional recurrence-free survival (LRFS) rate was higher in IMRT replanning group (96.7 vs. 88.1 %, P = 0.022). No significant differences in distant metastasis-free survival (DMFS), progression-free survival (PFS) and overall survival (OS) were observed between the two groups. 21.2 % patients in IMRT replanning group and 28.8 % patients in IMRT group had distant metastasis. In multivariable analysis, IMRT replanning was identified as an independent prognostic factor for LRFS (hazard ratio 0.229; 95 % CI 0.062-0.854; P = 0.028), but not for DMFS, PFS and OS. Conclusions. IMRT replanning provides an improved LRFS for stage T3/T4 NPC patients compared with IMRT. Distant metastasis remains the main pattern of treatment failure. No significant advantage was observed in DMFS, PFS and OS when adaptive replanning was used (AU)

RESUMEN

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