Sir, it was with great interest that I read the recent letter published in the BDJ Special precautions (BDJ 2005; 198: 628).

We have been looking into this subject. There have been various studies carried out on the effects of Zometa and Aredia on bony metastasis from tumours such as breast cancer and prostate cancer. It has been found to reduce the overall risk of developing bone complications and also helps reduce bone pain. The expert panel of the American Society of Clinical Oncology state that bisphophonates reduce bone complications but do not, however, have an impact on patient survival, ie they improve the quality of life rather than cure the disease.

In the last few years oncologists/ surgeons have become aware of an increase in the number of patients with osteonecrosis, in patients taking either Zometa or Aredia.

Osteonecrosis is a rare and poorly understood condition that is often mistaken for other conditions of the jaw such as osteomyelitis, exposed bone, necrosis and impaired healing after a dental procedure. The symptoms of osteonecrosis include pain, swelling, gum infections, loosening of teeth, poor healing of gums — especially after dental treatment — and numbness or heavy feeling in the jaw. Treatment for osteonecrosis includes antibiotics, oral rinses and protective mouth guards.

Osteonecrosis and its complications can lead to chronic pain, dysfunction and disfigurement all of which may be difficult to treat.

There have been various papers published about the association of Zometa, Aredia and osteonecrosis. A case report published in the Journal of Oral Pathology and Medicine in February 2005 (J Oral Pathol Med 2004; 33: 1–4) looked at 10 patients with osteonecrosis of the jaw that appeared following cancer chemotherapy. Six of the patients had bone metastases from breast cancer and four had multiple myelomas. All 10 patients had osteonecrosis of the mandible; 50% also had maxillary involvement. In all 10 patients the histopathological diagnosis was of chronic osteomyelitis without evidence of metastatic disease of the bone. Seven of the patients had a tooth extraction prior to the onset of the osteonecrosis. All the patients had received Zometa and/or Areida as part of their treatment. The authors conclude that osteonecrosis appears to have a relationship with the use of the bisphosphonates Zometa and Aredia.

More research is needed, as these patients are usually on other treatments such as chemotherapy or radiotherapy that may contribute to the development of osteonecrosis.