Safety of I.V. Nonnitrogen Bisphosphonates on the Occurrence of Osteonecrosis of the Jaw: Long-Term Follow-Up on Prostate Cancer Patients

IntroductionThe aim of the study was to disclose information about the recently incorporated bisphosphonates therapies used to treat prostate cancer patients and their potential risks because the chemical nature and nitrogen content varies among the available drugs on the market.Patients and MethodsThree hundred twenty-four consecutive prostate cancer patients were submitted to bisphosphonates therapy after antiandrogen treatment was started. Zoledronic acid was administered monthly (n = 45), bimonthly (n = 15), trimonthly (n = 19), and semestrally (n = 15), and monthly intravenous clodronate was administered in an additional 156 cases. Fourteen additional cases switched the drugs during the course of the treatment.ResultsAfter a median follow-up of 54 ± 24 (control), 63 ± 7 (clodronate), and 54 ± 6 months (zoledronic acid), the only 2 patients (0.6%) who developed osteonecrosis of the jaw (ONJ) occurred in those who switched the drug.ConclusionThis study is the longest and the largest ever reported on bisphosphonates usage in prostate cancer patients. ONJ seems to be exclusively related to nitrogen content bisphosphonates.