Mandibular radiation dose modifies the association between post-chemoradiotherapy dental extraction timing and osteoradionecrosis risk: a retrospective cohort study

Abstract

This retrospective study evaluated whether the association between post-CCRT dental extraction timing and osteoradionecrosis of the jaw (ORNJ) risk is modified by mandibular radiation exposure in patients with locally advanced nasopharyngeal carcinoma (LA-NPC) treated with definitive concurrent chemoradiotherapy (CCRT). Methods: A total of 247 patients who did not undergo pre-CCRT dental extraction but underwent post-CCRT extraction were analyzed. Mandibular radiation exposure was quantified using EQD2. Associations between clinical, tumoral, dental, and dosimetric variables and ORNJ were assessed using multivariable logistic regression, including assessment of EQD2–timing interaction. ROC analyses were performed to evaluate discriminative performance and estimate exploratory thresholds. ORNJ developed in 23 patients (9.3%). Mandibular EQD2 was independently associated with ORNJ risk (OR 2.10 per 5 Gy; 95% CI 1.40–3.15; p