Main Session
Sep 29
PQA 07 - Head and Neck Cancer, Lung Cancer/Thoracic Malignancies, and Nursing and Supportive Care

3485 - Personalized Prediction of Radiation-Induced Oral Toxicity Using a Nomogram in Nasopharyngeal Carcinoma

03:45pm - 05:00pm ET
Poster Hall - Exhibit Hall A
Screen: 6
POSTER

Presenter(s)

Rui Guo, MD - Sun Yat-Sen University Cancer Center, Guang Dong Province, Guangdong

R. Guo1, X. Jiang1, S. H. Zhou1, J. Y. Lin1, W. W. Zhang1, L. Chen1, G. Wang1, Y. P. Mao1, L. Tang1, G. Q. Zhou1, J. Hu2, J. B. Li3, K. B. Yang1, and J. Ma1; 1Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, China, 2Sun Yat-sen University Cancer Center, Guangzhou, China, 3Clinical Trials Centre, Sun Yat-sen University Cancer Centre, Guangzhou, China

Purpose/Objective(s): Despite improved survival in nasopharyngeal carcinoma (NPC), radiation-induced oral toxicity (RIOT) remains a major clinical challenge, impairing quality of life (QoL) and treatment adherence. No validated tool exists to quantify RIOT risk in NPC patients receiving intensity-modulated radiotherapy (IMRT). This study aimed to identify risk factors for RIOT, construct a predictive nomogram, and propose dose constraints.

Materials/Methods: A retrospective cohort of 203 NPC patients treated with definitive IMRT between 2016 and 2018 was analyzed. Dose–volume histogram parameters of oral cavity–related organs were extracted from treatment plans. Predictor selection was performed using least absolute shrinkage and selection operator (LASSO) logistic regression. A multivariable nomogram was constructed to estimate individualized RIOT risk. Model performance was evaluated using area under the receiver operating characteristic curve (AUC), mean absolute error (MAE), and decision curve analysis (DCA). RIOT and oral health outcomes were assessed using the General Oral Health Assessment Index (GOHAI).

Results: RIOT occurred in 49.8% of patients. Three predictors—parotid volume receiving =25 Gy (PAV25), mean mandibular dose (MAmean), and mandibular volume receiving =35 Gy (MAV35)—were incorporated into the nomogram (AUC = 0.771, MAE = 0.014). Based on the 33rd and 66th percentiles of total scores, patients were stratified into low (<106), intermediate (106–131), and high-risk (=132) groups. DCA demonstrated greater net benefit over “treat-all” or “treat-none” strategies. Recommended dose constraints to reduce RIOT were: PAV25 < 80%, MAV35 < 73%, and MAmean < 42 Gy.

Conclusion: The nomogram enables early identification of NPC patients at high risk of RIOT, supporting individualized radiotherapy planning and targeted toxicity prevention to improve long-term outcomes.