Bisphosphonate-induced osteonecrosis of the jaw: Risk factors and diagnostic utility of bone scans

Abstract

9052 Background: Osteonecrosis of the jaw (ONJ) is a serious long-term effect of intravenous bisphosphonates. We report characteristics of patients with ONJ at Roswell Park Cancer Institute (RPCI) and utility of bone scans in its diagnosis. Methods: Patients were identified using RPCI database. ONJ diagnosed was staged using the system used for jaw osteoradionecrosis (Schwartz et al, Am J Clin Oncol, 2002). Controls included patients receiving bisphosphonates between July 2002 and 2006. Routine whole body bone scans were reviewed for jaw uptake. Statistical analysis was done using SAS 9.1. Results: Three hundred and fifty-four patients received intravenous bisphosphonates between July 2002 and 2006. Twenty-four (7%) were diagnosed with ONJ. Among patients with ONJ, fifteen (63%) had breast cancer, eight (33%) had multiple myeloma and one (4%) had lung cancer. Mean age was 56.8 years. (SD= 9.1) Thirteen patients (54%) had tobacco use, five (21%) had diabetes, nine (37.5%) had hypertension and twenty-three patients (96%) received chemotherapy. Five patients (21%) had caries, three (12.5%) had dental surgery, nine (37.5%) had periodontal disease, thirteen (54%) had extractions and one (4%) had prior dental trauma. Twenty-two patients (92%) presented with pain. Twelve patients (50%) had ONJ Stage 1, eight (33%) Stage 2 and four (17%) Stage 3. Median duration of exposure to bisphosphonates was 39 months. The difference between the average number of infusions in the ONJ group (11.2, CI: 11.3, 20.3) and control group (7.2, CI: 6.2, 8.2) was found to be significant (p<0.0009). Three patients (12.5%) had progressive ONJ. Thirteen patients with ONJ had bone scans and twelve (92%) showed jaw uptake. Among controls, one hundred and eighty-three had bone scans and one hundred and twenty-eight (70%) showed jaw uptake. This difference was not significant. (p=0.114, two-tailed Fisher's exact test). Conclusions: In our study, chemotherapy, smoking, prior dental extractions and the number of bisphosphonate infusions appear to be risk factors for ONJ. It has been recently reported (Chiandussi et al., Dentomaxillofacial Radiol. 2006) that bone scans can be used as a screening tool for ONJ, however, in our series jaw uptake on bone scan was not a reliable predictor for the development of ONJ. No significant financial relationships to disclose.