Doctors at Long Island Jewish (LIJ) Medical Center recently discovered a link between a common chemotherapy drug and a serious bone disease called osteonecrosis of the jaw (ONJ).
The discovery, published in the Journal of Oral and Maxillofacial Surgeons, prompted both the US Food and Drug Administration (FDA) and Novartis, the manufacturer of bisphosphonates used in cancer chemotherapy, to issue warnings earlier this fall to physicians and dentists about the risk for this potential adverse effect. ONJ is a condition in which the bone tissue in the jaw fails to heal after minor trauma such as a tooth extraction, causing the bone to be exposed. The exposure can eventually lead to infection and fracture and may require long-term antibiotic therapy or surgery to remove the dying bone tissue.
The chief of the Division of Oral and Maxillofacial Surgery at LIJ, Salvatore Ruggiero, DMD, MD, and his staff reported that they were struck by a cluster of cancer patients with necrotic lesions in the jaw -- a condition they rarely saw, in only about one to two patients a year. When they launched a study of patients' charts, they found that 63 patients diagnosed with this condition over a three-year period shared only one common clinical feature: they had all received long-term bisphosphonate therapy.
Bisphosphonates are commonly used in tablet form to prevent and treat osteoporosis in post-menopausal women. Stronger forms are widely used in the management of advanced cancers that have metastasized to the bone, where the disease often causes bone pain and possibly even fractures. Several cancers can involve or metastasize to the bone, including lung, breast, prostate, multiple myeloma and others. In cancer chemotherapy, the drugs are given intravenously, and usually for long periods of time.
In their study, Dr. Ruggiero and his staff teamed up with Bhoomi Mehrotra, MD, in the Division of Hematology-Oncology at LIJ, and doctors in the Oral-Maxillofacial Surgery Division at the University of Maryland Medical Center. Of the 63 patients diagnosed with ONJ between February 2001 and November 2003 at their centers, 56 were cancer patients who had received infusions of bisphosphonates for at least a year and seven were non-cancer patients who had been receiving long-term oral therapy for osteoporosis. The patients developed ONJ after normal bone trauma, such as a tooth extraction, while receiving bisphosphonate therapy. Rather than healing, the bone began to die, and the majority of patients required surgery to remove the diseased bone.
In the FDA MedWatch and Novartis alerts issued in late September, oncologists and dentists were advised of the addition of osteonecrosis of the jaw to the "Precautions" and "Adverse Reactions" sections on the labeling of injectable bisphosphonates, describing the spontaneous reports of the condition being found mostly in cancer patients. The alerts also recommend a dental examination with appropriate preventive dentistry in patients with risk factors such as cancer, chemotherapy, corticosteroids and poor oral hygiene prior to initiating treatment with bisphosphonates.