Treatment outcomes with whole-field versus split-field intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma.

Abstract

The purpose of this study was to present our comparison of the clinical outcome of patients with nasopharyngeal carcinoma (NPC) treated with whole-field intensity-modulated radiotherapy (whole-field-IMRT) or split-field-IMRT. We retrospectively studied 388 patients with M0 NPC. The median lower neck doses were 50 Gy in 1.35 Gy/fractions for the 240 whole-field-IMRT patients, and 50.4 Gy in 1.8 to 2.0 Gy/fractions for the 148 split-field-IMRT patients. The IMRT technique did not affect the overall survival (OS; P = .077) and locoregional control (P = .231) rates. However, the split-field-IMRT group had more locoregional recurrences at the whole neck (P = .005) but not at the nasopharynx (P = .968) or the lower neck (P = .485). The patients treated with split-field-IMRT (43.2%) had more grade III neck fibrosis than the patients who received whole-field-IMRT (18.3%; P < .001). Only 1 patient had temporal lobe necrosis in our study. Our study shows that whole-field-IMRT using a lower dose/fraction for the lower neck results in at least comparable locoregional control and less fibrosis compared to conventional fraction with split-field-IMRT.