A patient on high-dose denosumab with a recurrent abscess and an unrestorable molar
A 74-year-old woman is referred with a recurrent swelling over the lower left first molar (36). She has metastatic breast cancer and has received denosumab 120 mg subcutaneously every four weeks for the last three years, together with letrozole; she also takes prednisolone 5 mg daily for polymyalgia rheumatica. The 36 has a 7 mm mesial pocket, grade II mobility, a periapical radiolucency and a discharging sinus; the crown is a failing bridge retainer and the tooth is judged unrestorable. There is no exposed bone, no fistula tracking to skin and no sequestration. Her last denosumab injection was four weeks ago and the oncologist has said treatment will continue indefinitely. She is systemically well and apyrexial, HbA1c is 41 mmol/mol, and she also has a 46 root stump she would like removed. She asks whether "the injection" needs to be stopped before treatment.
1. Stratify her risk of medication-related osteonecrosis of the jaw, and state exactly what she must be told before treatment.
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Risk category. Denosumab 120 mg every four weeks for metastatic malignancy is high-dose antiresorptive therapy and places her in the highest risk group for medication-related osteonecrosis of the jaw (MRONJ). Duration (three years), concurrent corticosteroid and the presence of active infection all add further risk. The subcutaneous route does not make it safer than intravenous therapy; dose and indication are what matter.
What she must be told, and what must be recorded
- The risk of MRONJ is materially higher than with osteoporosis dosing, and it can occur even with an atraumatic technique.
- MRONJ may present as exposed bone, a non-healing socket, pain, swelling or a sinus tract, and may be chronic and difficult to resolve.
- The alternatives: retain the tooth (with the risk of spreading infection), attempt restorative or endodontic retention (not feasible here), or extraction.
- Leaving a chronically infected, mobile tooth in a patient at high risk is itself a risk factor for MRONJ and for an urgent spreading infection.
- No blood test predicts individual risk. Serum CTX is not validated for denosumab-treated patients and must not be used to gate surgery.
What this presentation is. Without exposed bone or a probing-to-bone fistula she does not currently meet the criteria for established MRONJ; this is a chronic periapical and periodontal infection with a sinus. Document the clinical findings, take radiographs, and do not label it MRONJ prematurely - but treat it as an urgent problem in a high-risk patient.
2. Her oncologist asks whether the denosumab should be interrupted before extraction. How would you answer, and what are the alternatives to extraction?
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On the drug holiday question. For denosumab there is no established "drug holiday". Its half-life is roughly 26 days and its effect on bone turnover reverses within months of the last dose, but there is no evidence that interrupting it reduces MRONJ risk, and stopping has oncological consequences (skeletal-related events, and rebound vertebral fracture risk with abrupt cessation). The decision belongs to the oncologist; the dentist's job is to explain that surgery is needed, share the plan and the timing, ask them to confirm the drug continues, and document the exchange. Definitive treatment should not be deferred indefinitely waiting for a window that may never be offered.
Alternatives to extraction, and why they fail here
- Endodontic treatment does not address a 7 mm pocket with grade II mobility or a failing bridge retainer that must be replaced.
- Coronal reduction or root amputation leaves a root fragment in an infected site in a high-risk patient.
- Retaining the tooth means a chronic discharging infection and a real risk of an acute spreading infection that would require more urgent, more extensive surgery.
So extraction is the least risky of the available options, provided it is done atraumatically with primary closure.
The 46 root stump: remove it in the same session if it can be done atraumatically with primary closure; otherwise stage it. Also examine every remaining tooth now, because any future extraction carries the same risk while the drug continues.
3. Describe the surgical and follow-up protocol you would use for the extraction.
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Before surgery
- 0.2% chlorhexidine rinse; consider a pre-operative antibiotic according to local policy, recognising that evidence for prophylaxis against MRONJ is weak and practice varies; document the rationale either way.
- Adequate anaesthesia. Practice varies on vasoconstrictor use in antiresorptive patients; what matters is that anaesthesia is complete so the procedure is atraumatic.
- Written consent as described, and a note that the oncologist has been informed.
Surgical principles
- Minimise trauma: periotomes and elevators rather than forceps torque, section multi-rooted teeth, avoid periosteal stripping beyond what is needed.
- Remove sharp bony edges and smooth the socket walls; curette out granulation tissue and any apical pathology.
- Achieve primary closure, advancing a flap if needed and avoiding tension. Do not place an implant or graft at the same time.
After surgery
- Analgesia, chlorhexidine rinses, soft diet, and antibiotics if not given pre-operatively.
- Review at 1, 2, 4 and 8 weeks. A socket that has not healed by 8 weeks should be treated as suspected MRONJ and managed conservatively: no bone debridement, imaging, and discussion with oncology. Exposed bone without infection is Stage 1; with infection it is Stage 2; either way, conservative management first.
- Reinforce prevention: excellent oral hygiene, fluoride, and prompt reporting of any non-healing site, because her risk continues for as long as she receives denosumab and for years afterwards.