[Osteonecrosis of the jaw and bisphophonates in oncology]

Bisphosphonates are potent osteoclastic inhibitors that are indicated in the prevention of bone complications. They could also be of interest in the prevention of bone metastases. Several recent international publications have highlighted the onset of osteonecrosis of the jaw (ONJ) in patients treated with bisphosphonates. These osteonecroses manifest in the form of bone exposure, recent tooth mobility, swelling and inflammation and, occasionally, localised pain but they can remain asymptomatic for weeks or even months. The prevalence of these osteonecroses in cancer patients treated with bisphosphonates could range from 1 to 10%. In most cases (60 to 80%), ONJ develops after alveolo-dental surgery (e.g. tooth extraction). Length of exposure to bisphosphonate probably increases the risk. Our recommendations regarding the diagnosis, classification, prevention and treatment of cases of ONJ observed during bisphosphonate administration are based on published studies and our experience. It is obvious that the use of bisphosphonates is undoubtedly beneficial in the treatment of bone complications but the incidence of ONJ during long-term treatments and at high doses warrants preventive measures. These measures are straightforward : bucco-dental repair prior to treatment, good hygiene and regular monitoring during treatment. Current, non-invasive procedures are still permitted. In other cases, the suspension of treatment is indicated until healing is complete. The increase in the incidence of ONJs, serious adverse events, raises the issue regarding duration and administration of bisphosphonate treatment in the management of bone metastases. Studies are currently underway in an attempt to answer this issue.