Impact of dose volume parameters and clinical characteristics on radiation-induced acute oral mucositis for head and neck cancer patients treated with carbon-ion radiotherapy dose volume outcome analysis

Objectives To assess the predictive value of different dosimetric parameters for acute radiation oral mucositis (ROM) in head and neck cancer (HNCs) patients treated with carbon-ion radiotherapy (CIRT). Methods 44 patients with HNCs treated with CIRT were evaluated for acute ROM which was defined as severe when the score >= 3 (acute ROM was scored prospectively using the Radiation Therapy Oncology Group (RTOG) score system). Predictive dosimetric factors were identified by using univariate and multivariate analysis. Results Male gender, weight loss >5%, and total dose/fractions were related factors to severe ROM. In multivariate analysis, grade >= 3 ROM was significantly related to the Dmax, D10, D15, and D20 (P < 0.05, respectively). As the receiver operating characteristics (ROC) curve shows, the area under the curve (AUC) for D10 was 0.77 (p = 0.003), and the cutoff value was 51.06 Gy (RBE); The AUC for D15 was 0.75 (p = 0.006), and the cutoff value was 42.82 Gy (RBE); The AUC for D20 was 0.74 (p = 0.009), and the cutoff value was 30.45 Gy (RBE); The AUC for Dmax was 0.81 (p < 0.001), and the cutoff value was 69.33 Gy (RBE). Conclusion Male gender, weight loss, and total dose/fractions were significantly association with ROM. Dmax, D10, D15 and D20 were identified as the most valuable predictor and we suggest a Dmax limit of 69.33 Gy (RBE), D10 limit of 51.06 Gy (RBE), D15 limit of 42.82 Gy (RBE), and D20 limit of 30.45 Gy (RBE) and for oral mucosa.