Denosumab, a non-restorable molar and a patient who wants it out
Mrs Lee, 71, has breast cancer with bone metastases. She has received denosumab 120 mg subcutaneously every 4 weeks for 36 months, and before that had zoledronic acid monthly for 12 months. She also takes letrozole, calcium with vitamin D, and ramipril for hypertension. She is a non-smoker with good oral hygiene, and has never taken corticosteroids or anti-angiogenic drugs. Her medical oncologist has told her that 'dental treatment is fine'. Tooth 46 is non-restorable: it has been root-treated previously, has a cast post, a recurrent periapical radiolucency, and a fractured mesial cusp with secondary caries below the margin. It is currently symptom-free, and the adjacent 47 was extracted two years ago. She asks for the tooth to be removed because she does not want trouble later, and she mentions a plane trip in three weeks.
1. How would you stratify her risk of medication-related osteonecrosis of the jaw, and which factors drive that risk?
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Her risk is elevated but extraction is not absolutely contraindicated. The relevant factors are:
- Potency and indication - high-dose antiresorptive therapy for malignancy carries a higher risk than osteoporosis dosing, because the doses are larger and more frequent.
- Cumulative exposure - denosumab for 36 months exceeds the commonly cited 2-year threshold, and she had 12 months of zoledronic acid before that. Risk accumulates across agents, and zoledronic acid is retained in bone for years.
- The procedure itself - extraction, especially with bone removal or periosteal stripping, is the classic trigger. Most MRONJ follows a dentoalveolar procedure.
- Local factors - she has good oral hygiene and is a non-smoker, which is protective. Diabetes and corticosteroid use would increase risk but are absent.
- Concurrent treatment - I would check whether any anti-angiogenic agent such as bevacizumab is planned, because that compounds risk.
What risk stratification is not - a serum CTX level is not validated for predicting MRONJ in patients on denosumab, and I would not use it to decide. Her absolute risk of MRONJ after a single atraumatic extraction is in the order of a few per cent, not a certainty, and that is the figure I would give her.
Conclusion - the tooth is non-restorable and has a periapical lesion, so leaving it untreated carries its own risk of infection and sepsis in an immunosuppressed patient.
2. What alternatives would you consider, and how would you coordinate with her oncology team?
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Alternatives
- Retain the tooth - not realistic here: it has a cast post, a recurrent periapical lesion and subgingival caries. Retreatment with apical surgery would be a more invasive procedure with a higher MRONJ risk than extraction.
- Extraction with primary mucosal closure - the conventional choice for a non-restorable infected tooth.
- Do nothing - unacceptable, because a chronic periapical infection in a patient on antiresorptives and chemotherapy can progress to a serious infection and makes future MRONJ management harder.
Coordination - I would contact her medical oncologist in writing before the procedure to confirm the current regimen, the prognosis, whether chemotherapy or an anti-angiogenic drug is planned, and the best timing, avoiding the neutropenic nadir. I would include the dental findings and the proposed plan.
I would not ask for denosumab to be stopped. The evidence for a drug holiday in denosumab-related MRONJ is weak, denosumab is not retained in the skeleton in the way bisphosphonates are, and interrupting it risks skeletal-related events. That decision belongs to oncology, not to me.
Also - I would examine the rest of her dentition now and treat any other disease preventively, so she does not need further extractions later. I would confirm her oral hygiene, consider high-fluoride toothpaste, and avoid implants and elective apical surgery.
3. If the extraction goes ahead, what operative and follow-up measures reduce the risk, and what must she consent to?
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Preoperative - 0.12% chlorhexidine rinse; confirm the oncologist's agreement and the timing; ensure the INR is irrelevant but check her platelet count if recent chemotherapy; plan a single, unhurried appointment.
Operative
- Atraumatic extraction with periotomes or forceps, avoiding a mucoperiosteal flap where possible and avoiding bone removal or alveolectomy.
- Minimal periosteal stripping; remove sharp bony edges only if essential.
- Achieve primary mucosal closure with sutures, and review the socket at one week to remove them.
- Some units use postoperative antibiotics (for example amoxicillin) and continue chlorhexidine; the evidence is limited but the practice is common, and I would agree it with the oncology team.
Follow-up - review at 1 week, 4 weeks, 3 months and 6 months, then until the mucosa is fully healed. She must report non-healing, exposed bone, pain, swelling, or numbness at once.
Consent - explain the diagnosis, the alternatives, and the estimated risk of MRONJ in plain terms; explain that healing may be slow, that further surgery in that area may be inadvisable, and that if MRONJ develops management is largely conservative. Explain that a denture may need relieving over the site. Confirm the flight in three weeks is compatible with a healed socket. Document the discussion.