Analysis of bone activity of jaws using scintigraphy on patients before, during and after treatment with IV bisphosphonates: A retrospective study.

摘要

Bisphosphonates are non-metabolized compounds with high affinity for bone mineral hydroxyapatite. These compounds are used in diagnosis and treatment of malignancies metastatic to bone. Currently, IV bisphosphonates are used to treat hypercalcemia of malignancy. There are also "off label" uses to prevent, minimize, or delay skeletal morbidity associated with metastatic bone disease. Osteonecrosis of the jaws is an intraoral complication that has been reported after administration of intravenous nitrogen-containing bisphosphonates. Bisphosphonate associated osteonecrosis (BON) may remain asymptomatic for many weeks or months and is usually recognized clinically by the identification of exposed bone in the oral cavity. Other clinical features of BON are pain, ulceration, necrotic bone and/or local inflammation of the mucosa. Though these are generally all of which are seen later in the disease process. It is theorized that nuclear medicine imaging may play a crucial role in the recognition and identification of these bone lesions earlier in the disease process. Due to the high bone affinity, bisphosphonates coupled to a gamma-emitting radioisotope have been used as bone-scanning agents. Technetium is most commonly used gamma-emitting radioisotope in conjunction with a bisphosphonate. In University of Iowa Hospitals and Clinics, the material of choice is technetium99 methylene diophosphonate (Tc99 MDP). Bisphosphonates have a long half-life in bone and long-term treatment with non-tagged therapeutic bisphosphonates may saturate bone adherence sites and interfering with a single-dose scanning agent used for bone scintigraphy. Alternatively, therapeutic bisphosphonates may alter bone physiology such that scintigraphic findings could be enhanced in some locations and decreased in others. Limitations of the use of scintigraphy in patients on bisphosphonate therapy include low resolution and a difficulty in differentiating between inflammation and metastatic disease especially during the latter stages of the disease. In an effort to understand the effects of this compound on scintigraphic imaging, this study will evaluate any potential changes during and after use of IV bisphosphonates that may confound imaging.