Potential Risk Factors of Bisphosphonate Related Osteonecrosis of the Jaws

Background: Bisphosphonates (BPs) are used to prevent bone resorption in osteoporosis and cancer patients. Long-term use of BPs is associated with osteonecrosis of the jaws (BRON). BRON is characterized by non-healing exposed bone, pain, recurrent infections and tooth loss, thereby reducing quality of life. Currently, curative therapies do not exist; therefore a better understanding of risk factors associated with BRON is essential for the development of preventative and therapeutic strategies. Objective: To identify potential risk factors associated with BRON. Methods: Patients with BRON were identified at the University of Minnesota Oral and Maxillofacial Surgery Clinic. BRON patients were classified according to the criteria established by the American Association of Oral Maxillofacial Surgeons. These criteria included patients who received at least one dose of intravenous (IV) BPs and no prior history of head and neck cancer/metastasis and/or head and neck radiotherapy. Patient data was collected, including age, sex, cancer type and number of IV BP doses. The BRON patient data was compared to control patients. Controls were defined as patients who received IV BPs without a diagnosis of BRON. A stepwise logistic regression analysis was used to determine potential risk factors. Results: Eighteen patients with BRON were identified. Of these 18 patients, 56% were women and 44% were men (mean age 64 years). The most frequent cancer types were breast cancer (44%) and multiple myeloma (28%). Eighty-nine percent of lesions occurred exclusively in the mandible, while 11% exclusively in the maxilla. Seventeen percent of the cases were categorized as stage I, 72% as stage II and 11% as stage III. The number of IV BP doses was positively associated (p<0.02) with BRON. Conclusion: Our current study shows the total number of IV BP treatments maybe a significant risk factor associated with BRON.