Finnish Study Links Denosumab to Jaw Necrosis in Breast Cancer

Medication-related osteonecrosis of the jaw affected 12.6% of breast cancer patients treated with denosumab for bone metastases during a Finnish registry study published on September 29, 2026, in Clinical Oral Investigations. Researchers at the University of Oulu found that dental procedures related to oral infections are associated with the condition.

Decoding the Finnish Nationwide Findings

When breast cancer metastasizes to the skeleton, therapies that curb bone degradation—known as antiresorptive drugs—play a crucial role in patient management. Yet, these medications can sometimes lead to osteonecrosis of the jaw (MRONJ), characterized by the localized death of jawbone tissue.

The retrospective nationwide study examined 652 Finnish breast cancer patients with bone metastases who received antiresorptive therapy between 2013 and 2015, following their medical trajectories through the end of 2020. Data compiled from the Finnish Institute for Health and Welfare and the Social Insurance Institution of Finland revealed distinct incidence rates based on drug regimens. Among patients treated with denosumab alone, 12.6% developed MRONJ during long-term follow-up. For patients who initially received bisphosphonates before switching to denosumab, the incidence rate was 15.3%. A small proportion of patients treated with bisphosphonates alone developed the condition.

In Plain English: The Clinical Takeaway

• What is MRONJ? A condition in which bone tissue in the jaw dies.
• Why dental checks matter: The study found associations between dental procedures related to oral infections and osteonecrosis of the jaw.
• Should you stop treatment? The findings alone do not warrant changing or discontinuing anti-resorptive treatment. Instead, the benefits and potential risks of treatment must be assessed on an individual basis.

The analysis also highlighted a clear correlation between dental procedures related to oral infections and the onset of jawbone necrosis. Tooth extraction and root canal treatment, in particular, were associated with a higher risk of the condition. However, doctoral researcher Miika Kujanpää noted that because the number of patients who underwent root canal treatment was small, the finding does not establish that the procedure itself causes osteonecrosis of the jaw.

Our results highlight the importance of identifying and adequately treating potential sources of oral infection before starting antiresorptive therapy, as well as monitoring oral health throughout treatment. This requires close collaboration between oncology and oral healthcare professionals. — Miika Kujanpää, doctoral researcher, University of Oulu

Antiresorptive Regimen	Patient Cohort Incidence of MRONJ
Denosumab Monotherapy	12.6%
Bisphosphonates Followed by Denosumab	15.3%
Bisphosphonates Monotherapy	Small proportion

Contraindications & When to Consult a Doctor

Nor should necessary dental treatment be withheld because of the associations observed. The study authors emphasize that future research should delve deeper into how treatment length, cumulative exposure, and medicine dosage relate to osteonecrosis of the jaw. Gaining clearer insights into the precise timeline connecting oral infections, dental interventions, and the onset of osteonecrosis of the jaw is also essential to help isolate the impact of each variable.

References

• Kujanpää, M., et al. (2026). Incidence and associated factors of medication-related osteonecrosis of the jaw in breast cancer patients with bone metastases: a nationwide registry study in Finland. Clinical Oral Investigations. DOI: 10.1007/s00784-026-07171-5

Disclaimer: This article is for informational purposes only and does not substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or qualified health provider with any questions regarding a medical condition.

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