Radiographic classification of mandibular osteoradionecrosis: A blinded prospective multi-disciplinary interobserver diagnostic performance study

Background & Purpose: Osteoradionecrosis (ORN) of the jaw is a severe complication affecting up to 15% of head and neck cancer patients treated with radiotherapy. The ClinRad system, endorsed by ASCO/ISOO/MASCC, incorporates radiographic features for ORN severity classification, but variability in imaging use and specialty expertise may impact diagnostic accuracy. This study benchmarks physician performance in diagnosing and staging ORN across specialties and imaging modalities. Materials & Methods: A retrospective diagnostic validation study was conducted at MD Anderson Cancer Center, involving 20 physicians from oral oncology, radiation oncology, surgery, and neuroradiology. Participants reviewed 85 de-identified imaging sets (CT and orthopantogram (OPG)) from 30 patients with confirmed ORN, diagnosing and staging cases using the ClinRad system. ROC analysis assessed diagnostic accuracy, while intra- and inter-observer agreement was measured using Cohen's and Fleiss kappa statistics. Results: Paired CT-OPG imaging significantly improved diagnostic performance across specialties (p < 0.001), with AUC values ranging from 0.79 (residents) to 0.98 (surgeons). However, inter- and intra-rater agreement remained low, with median Fleiss kappa values of 0.22, 0.13, and 0.05 for ClinRad stages 0/1, 2, and 3, respectively. No specialty demonstrated significantly superior diagnostic accuracy (p > 0.05). Conclusion: This study establishes a benchmark for radiographic ORN detection, revealing diagnostic variability across specialties. Findings emphasize the need for standardized imaging protocols, interdisciplinary training, and multimodal imaging to improve diagnostic accuracy.