To address whether the addition of
intensity-modulated radiotherapy (IMRT) compared to
three-dimensional conformal radiotherapy (3D-CRT) aggravate radiation-induced acute injury of locoregionally advanced
nasopharyngeal carcinoma (LANPC) patients with
induction chemotherapy (IC) followed by
concurrent chemoradiotherapy (CCRT). We conducted a prospective study of 182 patients in the stage III to IVb with biopsy-proven nonmetastatic LANPC who newly underwent
radiotherapy and sequentially received IC, followed by CCRT at our institution. Occurring time of radiation-induced toxicities were estimated and compared using the Kaplan-Meier method and Log-rank test. The most severe acute toxicities included
oral mucositis in 97.25% and
dermatitis in 90.11%. Subset analysis revealed that Grade 3-4 acute
dermatitis were significantly higher in the IMRT than 3D-CRT.
Oral mucositis and
dermatitis were the earliest occurrence of acute
injuries (2 years: 60.44% and 17.58%). Patients in IMRT group achieved significantly lower risk of bone marrow toxicity, but higher risk of
leukopenia and gastrointestinal injury. Multivariate analyses also demonstrated that IMRT, female gender and
hepatitis were the independent prognostic factors for bone marrow toxicity. In a combined regimen of IC followed by CCRT for the treatment of LANPC, IMRT seems to be an aggressive technique with a trend towards increased gastrointestinal and hematological toxicities, but decreased bone marrow toxicity than those treated with 3D-CRT. This study provides a comprehensive summary of prospective evidence reporting the side effects in the management of LANPC patients. We quantify the occurrence risks of
chemoradiotherapy-induced acute
injuries through analysis of time-to-event.