Determination of the Risk of Osteonecrosis of the Jaw in Patients with Bone Metastasis Treated with Intravenous Bisphosphonates

Aim of this study was to evaluate the risk of osteonecrosis of the jaw (ONJ) by using computerized tomography (CT) in cancer patients who received intravenous bisphosphonate therapy. This study included 15 cancer patients who received intravenous bisphosphonate therapy for a minimum of 12 months and was given palliative radiotherapy for bone metastases in our hospital. ONJ was defined as follows: (1) Exposed or otherwise necrotic bone in the maxillofacial region that has persisted for more than 8 weeks, (2) No history of irradiation of the jaw, (3) Current or previous treatment with a bisphosphonate. Median duration of bisphosphonate therapy was 17 (12-108) months. Paranasal CT was performed in all 15 patients to evaluate radiodensity of mandibula and maxilla. As a control group, 15 patients without a history of malignancy, for whom paranasal CT was performed to investigate sinusitis or rhinosinusitis, were evaluated. None of the patients in our study had lytic changes, periosteal reaction or sequestrum formation. There were coarsening of trabecular bone in two patients and trabecular rarefaction in one patient. Radiodensity of mandibula was significantly higher in patients receiving bisphosphonate therapy than in control subjects (511 +/- 226 HU vs. 358 +/- 93 HU, respectively, p: 0.026). Similarly, although not statistically significant, radiodensity of maxilla was higher in patients receiving bisphosphonate therapy than in control subjects (386 195 HU vs. 338 95 HU, respectively, p: 0.403). In conclusion, we suggest that increase in bone density and changes in trabecular bone may indicate bisphosphonates-induced bone remodeling and maxillofacial CT can be used as a screening test for ONJ and early intervention can be performed to prevent the developing ONJ in patients with detected changes in the bone matrix (i.e., trabecular bone). Larger prospective studies for the evaluation of predictive value of CT for ONJ are needed.