We would like to thank Dr. Sari and her colleagues for their interest in our article. The M.D. Anderson Cancer Center (MDACC) study they refer to was a retrospective chart review of patients with cancer who received intravenous bisphosphonate therapy for the prevention of complications associated with bone metastases. These patients with advanced cancer were receiving pamidronate or zoledronic acid 4 milligrams infusion every three to four weeks, rather than the once-yearly infusion zoledronic acid 5 mg examined as a treatment for osteoporosis in our study.
In addition to receiving higher doses of zoledronic acid more frequently, patients with advanced cancer are debilitated because of their underlying disease and chemotherapy associated with the treatment of their malignancies. These underlying factors place patients with cancer at higher risk of developing osteonecrosis of the jaw (ONJ) because of their altered wound healing and immunosuppression.
In the MDACC study, the rate of ONJ in patients with cancer was reported to be approximately 1 percent, significantly higher than the rate we found in patients with osteoporosis. Therefore, because of the differences in the risk factors between patients with cancer and patients with osteoporosis, we agree with Dr. Sari and colleagues that the incidence of ONJ would be expected to be rare in those with osteoporosis, as was found in our study.
In summary, it is important for dentists to recognize that the difference in the incidence of ONJ between patients with cancer and patients with osteoporosis is more likely due to the underlying disease, its treatment and the bisphosphonate dose, rather than the type of bisphosphonate used to treat the disease.
