UROLOGICAL ONCOLOGY

Prevalence and risk factors of bisphosphonate-associated osteonecrosis of the jaw in prostate cancer patients with advanced disease treated with zoledronate
Walter C, Al-Nawas B, Grötz KA, Thomas C, Thüroff JW, Zinser V, Gamm H, Beck J, Wagner W
Klinik für Mund-, Kiefer- und Gesichtschirurgie, Johannes Gutenberg-Universität Mainz, Mainz, Germany
Eur Urol. 2008; 54: 1066-72

• Background: In addition to other treatments, patients with prostate cancer (pCA) and bone metastasis receive bisphosphonates. Since 2003, a previously unknown side-effect of bisphosphonates-bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ)-has been described, and frequency has since increased. An exact incidence is still unknown.
• Objectives: The aim of this study was to assess the incidence and additional factors in the development of BP-ONJ.
  Design, Setting, and Participants: From July 2006 to October 2007, patients with advanced pCA and osseous metastasis receiving bisphosphonate therapy in the Department of Urology or Haematology and Oncology at the Johannes-Gutenberg-University Mainz, Germany, received a dental examination. In all, 43 patients were included.
• Measurements: Patients were checked for exposed bone, osteonecrosis, mucosal defects, inflammation, and oral hygiene. Further points were the applied bisphosphonate, co-medication, the duration of application, and possible trigger factors for BP-ONJ.
• Results and Limitations: Eight of 43 patients developed BP-ONJ (18.6%). All patients had received zoledronate at least 14 times. Two patients had received bondronate, and one patient had received pamidronate before switching to zoledronate. All patients had had a previous tooth extraction or a denture pressure sore, and all patients had received additional chemotherapy and corticosteroids.
• Conclusions: The reason for this relatively high incidence compared to other studies might be the prospective study design and thorough dental examination. In studies with such small numbers as have been published to date, nondetection or nonreported cases of BP-ONJ have an influence on the outcome. The incidence of BP-ONJ in patients with pCA might be an underestimated problem.
  
  
• Editorial Comment
  Bisphosphonates are widely given in patients with a high risk for, or manifest, bone metastases. In most patients with advanced prostate cancer, this drug is considered standard therapy. Recently, the risk for developing dental complications became evident but neither the true incidence nor risk factors are known. This paper helps to clarify the situation.
  Nearly 19% of patients from this uncontrolled series suffered from some sort of osteonecrosis. Most were highly pretreated with biphosphonates and steroid and/or docetaxel therapy. Urologists should be aware of this possible complication and should work closely together with experienced dentists. Special attention should be given to multimodally treated patients.

Dr. Andreas Bohle
Professor of Urology
HELIOS Agnes Karll Hospital
Bad Schwartau, Germany
E-mail: boehle@urologie-bad-schwartau.de