Many people who currently take or who have taken bisphosphonates are being denied essential dental procedures because of undue fears about bisphosphonate-induced osteonecrosis of the jaw, according to a specialist in oral pathology.
“The phenomenon of ONJ seen in patients who happen to be on a bisphosphonate can also be seen in patients who have never had a bisphosphonate, but whether the bisphosphonate is directly responsible for this occurrence has not been scientifically [proved],” said Ellen Eisenberg, D.M.D., head of oral and maxillofacial pathology at the University of Connecticut Health Center in Farmington.
Dr. Eisenberg, a pathologist and a consultant for Novartis, said she is unable to tell the difference between osteonecrosis of the jaw (ONJ) that has occurred in patients treated with radiation for head and neck cancer, in patients treated with intravenous or long-term oral bisphosphonates, or in patients who have not received either treatment.
“If you were to take something like 15 microscopic slides from dead bone of the jaw in such patients and ask me to tell what the difference is amongst them, I can tell you this: They all look the same,” she said.
The definitive diagnosis of bisphosphonate-associated ONJ requires exposed bone in the jaw for 8 weeks or longer. Although most cases involve a history of a surgical procedure in the mouth, most typically a tooth extraction, 40% of cases report sudden exposure of bone for no reason.
“The jaw is a high traffic area that is subject to extreme forces, and therefore it is very likely that a patient may not recall a particularly traumatic event. Nevertheless, that trauma occurred, and that preceded the exposure of the bone,” Dr. Eisenberg said at the annual Chicago Supportive Oncology Conference.
Dr. Eisenberg emphasized that the pathogenesis of ONJ is presumptive, based on the presumed alteration in the dynamic inhibition, resorption, and apposition of bone. “However, we do not know with any scientific certainty that this [presumed alteration] is, indeed, the cause,” she said.
Until results from definitive studies show that bisphosphonates, whether oral or intravenous, are indeed the cause of ONJ, it is imperative that any patient about to embark on bisphosphonate therapy get a thorough dental examination, so that any potential sites of infection or inflammatory disease can be eliminated, Dr. Eisenberg said.
Patients who develop ONJ have a host of comorbidities which may be cofactors in play. Right now, it is not scientifically sound to focus on just bisphosphonates as the cause, since there may be other reasons for developing ONJ, she maintained. For instance, patients with metastatic breast cancer or multiple myeloma suffer from widespread disease, with all of its implications, Dr. Eisenberg said.
Even older age can predispose an individual to develop ONJ, she added.
Dr. Eisenberg also suggested that a genetic polymorphism may predispose individuals to develop bisphosphonate-associated ONJ. “This is my suspicion, and it is purely conjecture, but I think that there is a subset of individuals who may be susceptible because their genetic profile predisposes them to the complication,” she said.
“What that genetic polymorphism is, I don't know, but we cannot dismiss the fact that only a very small proportion of people actually get ONJ. What is it that makes them vulnerable? Much more work needs to be done before we single out bisphosphonates as the sole cause.”
Darn, no answers. Since I have already broken bones and my vertebra very weak from osteoporous, I must take these drugs. Meanwhile, I can't take a dentist to take my arthritis serious, leaving me in the chair to wait for 45 minutes before treatment.