Prognostic Factors of Mandibular Osteoradionecrosis Including Accurate Colocalization of Avulsions and Dosimetric Dental Mapping Software, a Case-control Study

Marion Renouf; Simon Auger; Loïc Campion; Grégory Delpon; Julie Longis; Cécile Dupas; Pauline Blery; Juliette Thariat; Mélanie Doré

doi:10.1016/j.ijrobp.2024.04.019

Prognostic Factors of Mandibular Osteoradionecrosis Including Accurate Colocalization of Avulsions and Dosimetric Dental Mapping Software, a Case-control Study

Int J Radiat Oncol Biol Phys. 2024 Apr 27:S0360-3016(24)00518-2. doi: 10.1016/j.ijrobp.2024.04.019. Online ahead of print.

Authors

Marion Renouf¹, Simon Auger², Loïc Campion³, Grégory Delpon⁴, Julie Longis⁵, Cécile Dupas², Pauline Blery⁶, Juliette Thariat⁷, Mélanie Doré⁸

Affiliations

¹ Institut de Cancérologie de l'Ouest, Nantes, France; Centre Hospitalier Départemental Vendée, La Roche Sur Yon, France. Electronic address: marion.renouf@gmail.com.
² Centre Hospitalier Universitaire, Nantes, France.
³ Institut de Cancérologie de l'Ouest, Nantes, France; Nantes Université, INSERM 1307, CNRS 6075, Université d'Angers, CRCI2NA, Nantes, France.
⁴ Institut de Cancérologie de l'Ouest, Nantes, France; Laboratoire SUBATECH, UMR 6457 CNRS-IN2P3, IMT Atlantique, Nantes, France.
⁵ Maxillofacial Surgery Department, Centre Hospitalier Universitaire, Nantes, France.
⁶ Centre Hospitalier Universitaire, Nantes, France; INSERM UMRS 1229, France.
⁷ Centre François Baclesse, Caen, France; Laboratoire de Physique Corpusculaire IN2P3/ENSICAEN/CNRS UMR 6534, Normandie Université, Caen, France.
⁸ Institut de Cancérologie de l'Ouest, Nantes, France.

PMID: 38685504
DOI: 10.1016/j.ijrobp.2024.04.019

Abstract

Purpose: Osteoradionecrosis (ORN) of the mandible remains a significant complication in the intensity modulated radiation therapy (IMRT) era. Dental dose cannot be predicted from heterogeneous IMRT dose distributions; mandibular dose metrics cannot guide dentist avulsion decisions in high-risk ORN situations. Using a mapping tool to report dental root dose, avulsions, and ORN sites, we re-examined ORN risk factors in a case-control study.

Methods and materials: From 2008 to 2019, 897 consecutive patients with oral cavity/oropharynx or unknown primary cancer undergoing IMRT were analyzed to identify ORN cases. These were matched (1 ORN/2 controls) retrospectively for tumor location, surgery, and tobacco consumption in a monocentric case-control study. Univariate and multivariate analyses integrated ORN factors and accurate dental dose data (grouped into 4 mandibular sectors). Generalizability was investigated in a simulated population database.

Results: A total of 171 patients were included. The median follow-up was 5.2 and 4.5 years in the ORN and control groups, respectively. The median time to ORN was 12 months. In univariate analysis, post-IMRT avulsions at the ORN site (hazard ratio [HR] = 3.6; 95% confidence interval [CI] = 1.5-8.9; P = .005), tumor laterality (HR, 4.4; 95% CI, = 1.4-14, P = .01), mean mandibular dose (HR, 1.1; 95% CI, = 1.01-1.1; P = .018) and mean dose to the ORN site (HR, 1.1; 95% CI, = 1.1-1.2; P < .001) correlated with higher ORN risk. In multivariate analysis, mean dose to the ORN site (HR, 1.1; 95% CI, = 1.1-1.2; P < .001) and post-IMRT avulsions at the ORN site (HR, 4.6; 95% CI, = 1.5-14.7; P = .009) were associated with ORN. For each increase in gray in dental dose, the ORN risk increased by 12%. Simulations confirmed study observations.

Conclusions: Dental dose and avulsions are associated with ORN, with a 12% increase in risk with each additional gray. Accurate dose information can help dentists in their decisions after IMRT.