Osteonecrosis of the jaw associated with intravenous bisphosphonate therapy—A single institution experience

18553 Background: Osteonecrosis of the jaw (ONJ) is a debilitating disease that has been associated with cancer therapy. Recently a link between ONJ and chronic intravenous (IV) bisphosphonates has been suggested. We assessed the incidence of ONJ and its risk factors in patients treated with IV bishosphonates at our institution. Methods: All patients with a cancer diagnosis treated at our institution with at least four cycles of either IV Zoledronic Acid, Pamidronate, or a combination of both, from 2000–2005 were evaluated using outpatient records. Patients with ONJ were identified and their characteristics were compared to all patients receiving bisphosphonate therapy. Results: One hundred and twenty-one patients were evaluated, 36 Male and 85 Female. Median age- 62 (Range 34–85). Seventy-six had metastatic Breast cancer, 25 Prostate, 7 Lung, 3 Colorectal, 3 Renal, 2 unknown primary, 1 each of Penile, Bladder, Seminoma, Lymphoma and Melanoma. Forty patients received Pamidronate infusions alone, 51 Zoledronic Acid alone and 30 a combination of the two. The median number of Pamidronate infusions was 8 (Range 4–10), Zoledronic infusions 10.7 (Range 4–32), and a combination of pamidronate and zoledronic acid was 12 (Range 5–66). Three patients developed ONJ. All 3 patients were female, had a median age of 62 (range 52–74) and had metastatic breast cancer. The median number of bisphosphonate infusions prior to the development of ONJ was 35 (Range 18–47). All patients had chest wall radiotherapy and 1 had chemotherapy and steroids. No patients had dental procedures or prolonged antibacterial therapy. Conclusions: ONJ is a complication associated with IV Bisphosphonate therapy. Our study suggests that female sex, zoledronic acid, and prolonged administration of bisphosphonates, may confer an increased risk for the development of ONJ. Further prospective studies with adequate power are needed to clarify what patients are most at risk for developing ONJ and what measures are needed to prevent its occurrence. No significant financial relationships to disclose.