Jaw bone death risk emerges as hidden cost of breast cancer drug therapy
A Swedish study of 220 breast cancer patients found that high-dose bone-protective drugs—standard treatment for preventing skeletal complications—can trigger a serious jaw condition in a small but clinically significant subset. The finding raises questions for oncologists, insurers, and pharmaceutical companies about how to balance the proven benefits of these medications against rare but severe side effects.
Originaltitel: Medication-related osteonecrosis of the jaw in breast cancer patients: a longitudinal observational Swedish study of oral health and antiresorptive use.
Höga doser antiresorptiva läkemedel för benskörhet hos bröstcancerpatienter fördubblar risken för käkbennekros (MRONJ) — en allvarlig biverkning som kliniker och inköpare måste väga mot skelettskydd. En svensk långtidsstudie vid Malmö universitet följde 220 bröstcancerpatienters munhälsa från 2015 till 2020. Medan biannuell låg-dosbisfosfontbehandling gav noll MRONJ-fall utvecklade 11,9 procent i högdosgruppen sjukdomen — statistiskt signifikant (p < 0,001). Tandutdragningar, mandibulär lokalisering och kumulativ läkemedelsmängd var huvudsakliga riskfaktorer. Märkvärt utvecklades närmare 42 procent av fallen spontant utan tandkirurgi. Studien från Malmö universitet, Region Värmland och Region Västra Götaland slår fast att munhälsebedömning före höga doser antiresorptiva måste bli rutinstandard. Regionvården behöver uppdaterad protokoll för tandbehandling vid skelettmetastaser och tydliga byte-kriterier mellan bisfosfoner och denosumab för att minimera MRONJ-incidensen.
BACKGROUND: Breast cancer is one of the most common cancers among women, with improved therapies reducing mortality. Antiresorptive (AR) therapy is crucial for managing bone loss and skeletal complications in patients with cancer. However, high-dose AR therapy may carry a significant risk of medication-related osteonecrosis of the jaw (MRONJ). This study aimed to investigate the incidence of MRONJ and its risk factors in patients with diagnosed breast cancer undergoing either biannual postoperative bisphosphonate therapy or high-dose AR therapy. METHODS: This study followed 220 female patients receiving AR therapy in Sweden, from 2015 to 2020. Oral health status was assessed before and during AR therapy, collecting data on MRONJ incidence, dental procedures, and data on breast cancer characteristics. Statistical analyses included Fisher's exact tests, and group differences in Kaplan-Meier curves were assessed using the log-rank test. p < 0.05 was considered statistically significant. RESULTS: The cohort comprised 119 patients on biannual AR therapy and 101 patients on high-dose AR therapy. Nine patients (4.0%) developed bone metastases and transitioned to high-dose AR therapy after a mean interval of 237 days; of these, 55.5% subsequently switched from bisphosphonates to denosumab. MRONJ cumulative incidence was 5.5% in the overall cohort and 11.9% in the high-dose group (p < 0.001); no MRONJ cases occurred in the biannual group. Tooth extractions (30.5%, p < 0.001), localisation to the mandible (83.3%, p = 0.039) and number of AR doses (p = 0.004) were significantly associated with the development of MRONJ. Notably, spontaneous MRONJ accounted for 41.7% of cases. Baseline DMFT did not differ, but MRONJ patients had a higher DMFT increment during follow-up. CONCLUSIONS: This study identifies a significant association between high-dose AR therapy and the development of MRONJ in breast cancer patients, with tooth extractions, mandibular localisation, and cumulative AR exposure identified as risk factors. MRONJ was not observed in the biannual AR therapy group. These findings underscore the importance of comprehensive dental assessments and early risk stratification.