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Bisphosphonate ONJ Risk — SCE Rheumatology MCQ

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ModerateMetabolic Bone DiseaseBisphosphonate ONJ RiskSCE Rheumatology

A 55-year-old man with metastatic prostate cancer develops exposed mandibular bone that persists for 3 months after a dental extraction. He previously received oral alendronate for 7 years and now receives intravenous zoledronic acid at oncology dosing. He also takes prednisolone and has periodontal disease. Which statement about risk factors for bisphosphonate-associated osteonecrosis of the jaw is most accurate?

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Correct answer: E — Risk rises with potent parenteral and cumulative exposure, cancer or corticosteroid therapy, poor oral health and invasive dental procedures.

Explanation lettering: E = shown as A · D = shown as B · A = shown as C · B = shown as D · C = shown as E

C is correct. Recognised risk factors include greater antiresorptive potency, parenteral administration, higher cumulative exposure, cancer, concomitant corticosteroids or chemotherapy, periodontal or other dental disease, poor oral hygiene and invasive procedures such as extraction. This patient has several convergent risks: prolonged cumulative bisphosphonate exposure, oncology-dose intravenous zoledronic acid, malignancy, prednisolone, periodontal disease and recent extraction. Oral osteoporosis-dose bisphosphonates can cause ONJ, but their risk is substantially lower than that associated with intravenous oncology regimens, excluding B and D. Dental health is important but is not the sole determinant, excluding A. The risk is not wholly idiosyncratic; recognised drug-related, systemic and local factors permit risk stratification, excluding E.

Reference: Zoledronic acid Ennogen 4 mg/5 ml concentrate for solution for infusion, Summary of Product Characteristics, section 4.4 “Osteonecrosis of the jaw”, revised 22 August 2025. https://www.medicines.org.uk/emc/product/101300/smpc