Possible delayed onset of osteonecrosis of the jaw in association with zoledronic acid

Objectives: To report a case of possible delayed-onset osteonecrosis of the jaw after treatment with zoledronic acid. Case summary: A 53-year-old white man with no history of allergic drug reactions had been diagnosed as having bronchial epidermoid carcinoma. He received therapy with docetaxel and zoledronate. Because of metastatic progression of the disease, he started treatment with irinotecan and zoledronate. The patient received 18 monthly cycles of zoledronate. One year after the last cycle of bisphosphonate therapy, the patient had one tooth extracted. Three weeks later, he complained of continuous mandibular pain and swallowing difficulties. A diagnosis of osteonecrosis of the jaw was made. Surgical treatment was chosen, with debridement and a mucosal flap, complemented with antibiotic therapy. Other potential aetiologic risk factors for osteonecrosis were investigated and could not be identified. Accordingly, a diagnosis of possible delayed onset jaw osteonecrosis associated with zoledronate was made. Discusions: Osteonecrosis of the jaws has recently emerged as a potential complication of bisphosphonate therapy in patients with metastatic cancer undergoing dental surgery. This is the first report of possible delayed-onset osteonecrosis of the jaw associated with zoledronate. Patients appear to remain at low risk of developing osteonecrosis even in the absence of zoledronate, especially after a dental extraction or oral surgery. Based on the Naranjo algorithm the adverse reaction was classed as possible.