Factors improving the outcome of patients re-irradiated with intensity-modulated radiotherapy (IMRT) for relapse or new head and neck cancer developed in irradiated areas.

Abstract

Patients with secondary/recurrent squamous cell head and neck cancer have poor prognoses. Re-irradiation is a treatment option. However, best technique to re-irradiate is not known. This study aims to evaluate the outcome of patients treated with curative-intent intensity-modulated radiotherapy (IMRT) re-irradiation (re-RT) for head and neck (H&N) cancers. Fifty patients with recurrent H&N cancers underwent fractionated IMRT re-RT. The median time between the two courses of radiotherapy was 22 months. The median dose of re-RT was 66 Gy. The median follow-up of surviving patients was 13.6 months. The median overall survival (OS) was 15.7 months, and the 1- and 2-year OS rates were 62.4% and 33.9%, respectively. On multivariate analysis, performance status (PS) 0-1 (HR, 0.518; 95% CI: 0.292-0.917; P=0.024) and 3D-RT use during the first irradiation course technique (HR, 0.415; 95% CI: 0.183-0.938; P=0.035) were favorable, independent of significant prognostic factors of OS. The median loco-regional progression-free survival (LRPFS) was 8.3 months, and, the 1- and 2-year LRPFS rates were 46.6% and 35.9%, respectively. On multivariate analysis, a surgical resection before re-RT (HR, 0.107; 95% CI: 0.027-0.428; P=0.002), a higher age (HR, 0.894; 95% CI: 0.833-0.960; P=0.002), a PS 0-1 (HR, 0.316; 95% CI: 0.140-0.715; P=0.006), and a long re-RT interval (HR, 0.970; 95% CI: 0.945-0.996; P=0.024) were favorable independent significant prognostic factors of LRPFS. The median progression-free survival (PFS) was 7.0 months and, the 1- and 2-year PFS rates were 45.0% and 30.4%, respectively. On multivariate analysis, a surgical resection before re-RT (HR, 0.129; 95% CI: 0.036-0.466; P=0.002), a PS 0-1 (HR, 0.399; 95% CI: 0.208-0.764; P=0.006) and, a long re-RT interval (HR, 0.958; 95% CI: 0.927-0.989; P=0.009) were favorable, independent significant prognostic factors. The early and late toxicities rates were 28% and 34%, respectively. Re-RT for H&N cancers can be curative, and the complications can be manageable but patients need to be strictly selected. Surgery before re-RT could improve the patient outcome. Dose and irradiation schedules should be prospectively evaluated.