OsteradionercrosisRisk factors for osteonecrosis of the jaw in oral cancer patients after surgery and eventual adjuvant treatment: The potential role of chemotherapy

Background and purposeTo identify the risk factors for osteonecrosis of the jaw (ONJ) in oral cancer patients after surgery with and without adjuvant therapy in a nationwide, population-based study.Material and methodsUsing the Taiwan National Health Insurance Research Dataset, we recruited patients with newly diagnosed oral cancer between 1997 and 2011. All of them underwent primary surgery. Data regarding demographic characteristics; tooth extractions; medications; and cancer treatments, including types of mandibular surgery, radiotherapy and platinum-based chemotherapy, were collected for analysis.ResultsWe identified 25,858 patients who suffered 2802 ONJ events. The ONJ incidence rate was 3.45 per 100 person-years. Lip cancer was associated with the highest risk of ONJ, followed by buccal mucosa, gum, mouth floor and tongue cancer. Using a time-dependent Cox regression model, multivariable analysis demonstrated that mandibulotomy (hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.01-1.55; p < 0.001), radiotherapy (HR, 1.39; 95% CI, 1.26-1.54; p < 0.001) and platinum-based chemotherapy (HR, 1.94; 95% CI, 1.56-2.41; p < 0.001) were significant risk factors for ONJ. In the subgroup analysis of patients receiving radiotherapy and patients not receiving radiotherapy, platinum-based chemotherapy remained a risk factor for ONJ.ConclusionsMandibulotomy, radiotherapy and platinum-based chemotherapy were associated with an increased ONJ risk. Chemotherapy was a risk factor regardless of whether radiotherapy was administered.