Osteoradionecrosis — ORE Part 1 MCQ

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ModerateOral SurgeryOsteoradionecrosisORE Part 1

A 60-year-old patient underwent radiotherapy to the mandible (60 Gy) for floor-of-mouth squamous cell carcinoma. Three months after completing treatment, there is persistent exposed bone in the left posterior mandible. The patient has not received antiresorptive or antiangiogenic medication, and there has been no dental extraction or other local trauma. What is the most likely diagnosis?

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Correct answer: D — Osteoradionecrosis of the jaw

The correct answer is D, osteoradionecrosis (ORN) of the jaw. The lesion is exposed mandibular bone persisting for 3 months within a field irradiated to 60 Gy; UK guidance identifies doses above 50 Gy, particularly 60 Gy or more, as increasing ORN risk. The conventional definition is exposed irradiated bone that fails to heal for 3 months, after excluding persistent or recurrent tumour. MRONJ is inappropriate because it requires current or previous antiresorptive/antiangiogenic drug exposure and, by definition, no history of jaw radiotherapy. Chronic osteomyelitis may coexist with ORN but does not best explain this classic post-radiotherapy presentation. Recurrent SCC must be excluded clinically and radiologically, but it is not the most likely diagnosis from the information given. Osteosarcoma would not be expected to present as persistent exposed bone confined to an irradiated mandibular field.

Reference: Faculty of Dental Surgery, Royal College of Surgeons of England. The Oral and Dental Management of Patients Before, During and After Cancer Therapy, sections 5.12–5.14, 2025. https://www.rcseng.ac.uk/-/media/Files/RCS/FDS/Publications/The-oral-and-dental-management-of-patients-before-during-and-after-cancer-therapy.pdf