Long-term bisphosphonates for osteoporosis: An introduction

Incidence of Osteonecrosis of the Jaw in Patients With Multiple Myeloma and Breast or Prostate Cancer on Intravenous Bisphosphonate Therapy

PURPOSE

Osteonecrosis of the jaw (ONJ) has been observed recently in patients with cancer who are receiving intravenous bisphosphonate (BP) therapy. The incidence of BP-associated ONJ has not been well established. The purpose of this study was to determine the incidence of ONJ in a cohort of patients with multiple myeloma (MM), breast cancer (BC), or prostate cancer (PC) who were receiving BP therapy.

PATIENTS AND METHODS

A retrospective chart review was performed. Medical record numbers were identified by ICD-9 codes: 203.0, 203.01, 174.9, and 185.0 for active MM, MM in remission, BC, and PC, respectively. Patients were included if they were evaluated and/or treated between January 1, 2000, and December 31, 2005, and had received zoledronic acid and/or pamidronate. Patients were excluded if they had a history of radiation therapy to the jaws or of tumors or cysts. ONJ was defined as clinical evidence of "exposed necrotic bone" in the mouth.

RESULTS

Through evaluation of 1,086 patient medical records, it was determined that 447 subjects met the inclusion criteria: 11 of 292 patients with MM (3.8%; 95% confidence interval [CI], 1.6%, 6.0%) had ONJ, as did 2.5% of 81 patients with BC (0%, 6.9%) and 2.9% of 69 patients with PC (0%, 5.9%).

CONCLUSION

The incidence of ONJ associated with intravenous BPs was at least 3.8 per 100 patients with MM, 2.5 per 100 patients with BC, and 2.9 per 100 patients with PC during the 5-year study period. The next phase of this study involves assessment of risk factors that differentiate these patients from those treated with BPs who do not develop ONJ.