Osteonecrosis of the jaw (onj) in prostate cancer patients: effect of preventive measures in a monoinstitutional experience

Background. Osteonecrosis of the Jaw (ONJ) frequency after antiresorptive treatment in prostate cancer patients largely varied in literature. Patients and Methods. Charts of all prostate cancer patients affected by bone metastases observed at the Oncology Unit of Alessandria Hospital in years 2005-2020 have been reviewed. ONJ frequency after antiresorptive treatment (bisphosphonates and/or denosumab) was investigated in prostate cancer patients with bone metastases undergoing preventive (before start of treatment) and/or screening (during treatment) evaluations, including oral inspection and panoramic dental radiography. Patients received antiresorptive agents according to international guidelines. Results. We examined charts of 120 patients receiving bisphosphonates (mostly zoledronic acid, or pamidronate or ibandronate) or denosumab or sequences of drugs, and evaluated for oral health, 112 being treated since 2006 after pre-treatment oral evaluation. Out of 120 total patients, 8 cases of Osteonecrosis of the Jaw (ONJ) were registered among prostate cancer patients treated at Alessandria Hospital: 2 ONJ cases were detected among 8 patients starting antiresorptive treatment before 2006 and without preventive visit, whereas 6 cases were found among 112 cases receiving dental visit before treatment start (6/112, 5.3%). Furthermore, other 8 ONJ cases in prostate cancer patients were referred by neighbour hospitals to the ONJ multidisciplinary group. Conclusions. Our preliminary data confirm that prostate cancer patients receiving bisphosphonates or denosumab are at not irrelevant risk of ONJ, even if in last decade less intensive schedules of antiresorptive drugs and measures of pre-treatment evaluation were adopted. Further evaluations have been planned to investigate if higher ONJ risk was associated to drug (denosumab versus zoledronic acid), prolonged treatment (> 2 years), pre-existing oral disease (periodontal disease, need for tooth extraction, ill-fitting dentures), and other potential predictive factors.