Efficacy and safety of PLDR‐IMRT for the re‐irradiation of recurrent NPC: A prospective, single‐arm, multicenter trial

Abstract

Salvage treatment of locoregionally recurrent nasopharyngeal carcinoma (NPC) requires weighing the benefits of re-irradiation against increased risks of toxicity. Here, we evaluated the outcomes of patients treated with intensity-modulated-based pulsed low-dose-rate radiotherapy (PLDR-IMRT) to enhance the curative effect of salvage treatment and reduce RT-related SAEs. A prospective clinical trial was conducted from March 2018 to March 2020 at multiple institutions. NPC patients who experienced relapse after radical therapy were re-irradiated with a median dose of 60 Gy (50.4-70 Gy)/30 f (28-35 f) using PLDR-IMRT. Thirty-six NPC patients who underwent PLDR-IMRT for locoregional recurrence were identified. With a median follow-up of 26.2 months, the objective response rate (ORR) of the entire cohort was 91.6%. The estimated mPFS duration was 28 months (95% CI: 24.9-31.1), and the estimated mLRFS duration was 30.4 months (95% CI: 25.2-35.5). The overall survival (OS) rate for all patients was 80.6%, the progression-free survival (PFS) rate was 75% and the cancer-specific survival (CSS) rate was 88.9% at 1 year. The LRFS and DMFS rates were 88.9% and 91.7%, respectively, at 1 year. A combination of systematic therapies could provide survival benefits to patients who experience NPC relapse (p < 0.05), and a Karnofsky performance status (KPS) score of ≥90 was a favorable factor for local control (p < 0.05). The incidence of acute SAEs (grade 3+) from PLDR was 22.2%, and the incidence of chronic SAEs was 19.4% among all patients. PLDR-IMRT combined with systematic therapy can effectively treat patients with locoregionally recurrent nasopharyngeal carcinoma and causes fewer adverse events than the rates expected with IMRT.

Re-Irradiation of Recurrent Head and Neck Cancers Using Pulsed Reduced Dose Rate Radiotherapy: An Institutional Series

“…A recently published trial examining PRDR-RT for Re-RT of recurrent NPC reported 1-year cancer specific survival rate of 80.6% as well as acute and late grade ≥3 toxicity rates of 22.2% and 19.4%, respectively. 17 These rates were lower than historical controls for standard dose rate IMRT-based Re-RT, especially given the anatomic difficulties of treating NPC with Re-RT. These findings suggest the potential benefits of PRDR-RT in reducing Re-RT toxicity while maintaining efficacy.…”

Re-irradiation of recurrent head and neck cancers using pulsed reduced dose rate radiotherapy: An institutional series

“…A recently published trial examining PRDR-RT for Re-RT of recurrent NPC reported 1-year cancer specific survival rate of 80.6% as well as acute and late grade ≥3 toxicity rates of 22.2% and 19.4%, respectively. 17 These rates were lower than historical controls for standard dose rate IMRT-based Re-RT, given the anatomic difficulties of treating NPC with Re-RT. These findings suggest the potential benefits of PRDR-RT in reducing Re-RT toxicity while maintaining efficacy.…”