Cancer
A multicenter, prospective, phase 2 trial on proton re-irradiation for patients with previously treated head and neck cancer
By Dee EC, Barker CA, Kalman NS and 22 others.
Abstract
Background
Re-irradiation (re-RT) for recurrent head and neck cancer (HNC) can be potentially curative but is constrained by significant toxicity. Proton therapy may improve the therapeutic ratio. This multicenter phase 2 trial evaluated the safety and efficacy of proton re-RT in patients with HNC.
Methods
Patients received prior HNC radiotherapy at a dose of ≥40 gray (Gy). Salvage surgery and/or systemic therapy before re-RT were permitted. Considering clinical status, two pragmatic treatment approaches were used: fractionated re-RT (F-Re-RT; 60-70 Gy) or QUAD shot re-RT (QS-Re-RT; 14.8 Gy per cycle, up to four cycles; maximum total, 59.2 Gy). Primary end points were locoregional recurrence-free rates at 12 months for F-Re-RT and at 6 months for QS-Re-RT, and a fixed-time, binary proportion analyzed using 90% Clopper-Pearson confidence intervals (CIs) and prespecified success thresholds (lower bound, >55% and >10%, respectively). Secondary end points included overall survival (OS), progression-free survival, the cumulative incidence of distant metastasis and locoregional recurrence, clinician-reported toxicity, and patient-reported outcomes.