WITHDRAWN: Radiation-Induced Acute Injury of Intensity-Modulated Radiotherapy vs. Three-Dimensional Conformal Radiotherapy in Induction Chemotherapy Followed by Concurrent Chemoradiotherapy for Locoregionally Advanced Nasopharyngeal Carcinoma: A Prospective Cohort Study

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Purpose:</jats:bold> Induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT) was the new standard treatment for locoregionally advanced nasopharyngeal carcinoma (LANPC). We aimed to address whether the addition of intensity-modulated radiotherapy (IMRT) compared to three-dimensional conformal radiotherapy (3D-CRT) aggravate radiation-induced acute injury of these patients.<jats:bold>Methods:</jats:bold> We conducted a prospective study of consecutive 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. Among 182 patients included, 87 (47.80%) were treated with IMRT and 95 (52.20%) with 3D-CRT. Occurring time of radiation-induced toxicities were estimated and compared using the Kaplan-Meier method and Log-rank test. <jats:bold>Results:</jats:bold> 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 (<jats:italic>P</jats:italic>=0.0482). 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 (Hazard ratio [HR]= 0.426, <jats:italic>P</jats:italic>=0.0009), but higher risk of leukopenia (HR=1.444, <jats:italic>P</jats:italic>=0.0344) and gastrointestinal injury (HR=2.383, <jats:italic>P</jats:italic>=0.0103). Multivariate analyses also demonstrated that IMRT (HR=0.429, <jats:italic>P</jats:italic>=0.0211), female gender (HR=2.070, <jats:italic>P</jats:italic>=0.0531) and hepatitis (HR=2.152, <jats:italic>P</jats:italic>=0.0552) were the independent prognostic factors for bone marrow toxicity. The use of IMRT was a predictive factor of significantly better short-term efficacy, whereas anemia was a significant independent predictor.<jats:bold>Conclusions:</jats:bold> 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.</jats:p>