Bisphosphonates May Lead to Jaw Osteonecrosis in Cancer Patients
Reuters 
January 3, 2006

The use of bisphosphonates to treat cancer patients with bone metastases may be complicated by osteonecrosis of the jaw, according to a report by researchers in Greece. Avascular osteonecrosis of the jaw (ONJ) has recently been reported as a complication of bisphosphonate use, the authors explain, but its incidence in cancer patients remains unclear. Dr. Meletios A. Dimopoulos from University of Athens and colleagues investigated the incidence of ONJ and its risk factors in 252 cancer patients treated with bisphosphonates. Seventeen patients (6.7%) were diagnosed with osteonecrosis of the jaw, the authors report in the December 1st Journal of Clinical Oncology. ONJ was not associated with the primary site of the cancer or the patient's sex or age, the results indicate. Duration of exposure to bisphosphonates, however, was strongly associated with the development of ONJ.  No patient who received fewer than 13 treatments with bisphosphonates developed ONJ. Patients with ONJ received a median of 35 infusions for 39.3 months, the report indicates, compared with a median of 15 infusions for 19 months in patients who did not develop ONJ. ONJ was significantly more common among patients treated with zoledronic acid than among patients treated with pamidronate (p < 0.001), the investigators observe. The development of ONJ was also associated with prior dental extraction or the use of artificial dentures.

"We conclude that ONJ is a complication that is correlated with long-term use of bisphosphonates," the authors write. "This might have implications in the current standards of use of these drugs in cancer patients."

"In view of the data reported by us as well as by others, caution is required for use of pamidronate and zoledronic acid beyond 2 years," the investigators conclude. "Furthermore, patients should improve their oral hygiene, whereas oncologists and dentists should be aware of this complication and its management."