Oral osteonecrosis associated with the use of zoledronic acid: first case of a patient with advanced pancreatic cancer and bone metastases.

while traditionally associated with radiation therapy for head and neck cancer, osteonecrosis of the jaw has recently been described mainly in breast cancer and multiple myeloma patients undergoing long-term intravenous bisphosphonate treatment [1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15]. Bisphosphonates are used to treat bone metastases, as they decrease bone resorption, primarily through their apoptotic effects on osteoclasts [16]. Studies indicate that zoledronic acid is the most potent bisphosphonate [17]. While there has been some variation in the reported frequency of osteonecrosis of the jaw development in patients treated with i.v. bisphosphonate, a recent large retrospective analysis by Hoff et al. reported that 0.72% of these patients ultimately developed osteonecrosis of the jaw [18]. This study also identified several risk factors associated with the development of osteonecrosis of the jaw, including high cumulative doses of bisphosphonates, poor oral health and dental extractions [18]. The high incidence of osteonecrosis of the jaw in patients with breast cancer and multiple myeloma was explained by the significantly higher cumulative dose and significantly longer duration of treatment that these patients receive, compared to patients with other malignancies [18]. A separate smaller analysis of osteonecrosis of the jaw in multiple myeloma patients identified the number of zoledronic acid infusions as the most important risk factor [19]. There has been no report of osteonecrosis of the jaw development in a patient with pancreatic cancer. Given that level of exposure to zoledronic acid has been identified as a significant risk factor, it is probable that the severity of pancreatic adenocarcinoma and the associated shorter duration of survival have prevented these patients from accumulating the required zoledronic acid exposure.