The Oxygenation–Nutritional–Inflammatory (ONI) index and the risk of osteoradionecrosis of the jaw in locally advanced nasopharyngeal carcinoma: a continuous multidimensional modeling analysis

Osteoradionecrosis of the jaw (ORNJ) remains a major late complication in patients with locally advanced nasopharyngeal carcinoma (LA-NPC) treated with definitive concurrent chemoradiotherapy (CCRT), for which current risk models based on dosimetric and dental factors do not fully explain inter-individual variability. To address this limitation, we evaluated the association between a novel Oxygenation–Nutritional–Inflammatory (ONI) index, derived from hemoglobin, albumin, and C-reactive protein, and ORNJ risk within a continuous modeling framework. A total of 298 LA-NPC patients treated with CCRT were retrospectively analyzed. Clinical, dental, and dosimetric variables were collected. ONI was calculated as a composite inflammatory-nutritional biomarker. Univariable and multivariable logistic regression analyses were performed to evaluate the independent associations of ONI and established clinical factors with ORNJ. ORNJ occurred in 25 (8.4%) patients. Patients who developed ORNJ had higher mandibular mean radiation dose and more extracted teeth, along with significantly lower ONI values. In multivariable analysis, mandibular mean dose (OR 1.23 per Gy, 95% CI 1.13–1.34; p < 0.001), number of extracted teeth (OR 1.38 per tooth, 95% CI 1.12–1.70; p = 0.002), and ONI (OR 0.88 per unit increase, 95% CI 0.78–0.99; p = 0.036) remained independently associated with ORNJ. ORNJ incidence decreased across increasing ONI tertiles (17.2%, 6.1%, and 2.0%; p < 0.001), supporting an inverse relationship between ONI and ORNJ risk. ORNJ appears to reflect a multifactorial process involving radiation dose, dental trauma, and systemic host vulnerability. ONI was independently associated with ORNJ risk and may contribute to individualized risk stratification, although these findings should be considered hypothesis-generating and require external validation. Graphical summary of the association between the Oxygenation–Nutritional–Inflammatory (ONI) index and osteoradionecrosis of the jaw (ORNJ) in patients with locally advanced nasopharyngeal carcinoma treated with concurrent chemoradiotherapy. Lower ONI values were associated with a higher probability of ORNJ, consistent with an inverse continuous relationship. Mandibular radiation dose and the number of extracted teeth represent established local determinants of risk. Together, these factors define a multidimensional risk profile. Findings are hypothesis-generating and require external validation.