A steadily rising rate of osteonecrosis of the jaw is being seen from radiation therapy and bisphosphonate treatment in oncology settings.

An audit of three Queensland public hospitals has shown that 160 cases of radiation-related osteonecrosis were seen among patients undergoing radiation treatment for head and neck cancers between 2003 and 2015.

A further 61 cases of medication-related osteonecrosis of the jaw were seen, of whom 29 were oncology patients taking high dose antiresorptive treatment as part of therapy for multiple myeloma (25% of cases), breast cancer 12%) or prostate cancer (10%).

Low dose bisphosphonates were responsible for half  the cases of osteonecrosis of the jaw seen by oral surgeons.

Rates of osteonecrosis of the jaw had increased steadily, reaching around 25 admissions per year from radiation and 10 admissions per year due to bisphosphonates by 2015, the review, published in Australian Dental Journal showed.

Patients who developed radiation-related osteonecrosis of the jaw were more likely to be male (80%) and had an average age of 63. They required an average length of  hospital stay of four days for osteonecrosis.

The authors of the review said the cases seen were likely at the more severe end of the spectrum, requiring treatment, and therefore the figures may have underestimated the true incidence of medication-relation osteonecrosis of the jaw in the community.

It also showed that osteonecrosis of the jaw was not confined to high dose bisphosphonate therapy used in oncology settings, but was also seen in osteoporosis treatment.

“Although the overall prevalence of medication-related osteonecrosis of the jaw in this patient group is low, this still translates into a substantial burden of disease due to the high number of patients treated for osteoporosis,” they wrote.

“This is an important finding … [it suggests] the number of osteoporosis patients affected by medication-related osteonecrosis of the jaw should not be underestimated,” they added.

The findings showed the need for optimum oral care for all patients receiving bisphosphonates, they suggested, especially when there were financial or access barriers to dental care.

“The findings of this study suggest that despite a considerable body of evidence reporting the efficacy of preventative measures in the reduction of both [radiation-related osteonecrosis]  and medication-related osteonecrosis of the jaw, this has not translated into a reduced number of patients presenting with these treatment complications.