PAMIDRONATE DISODIUM IN THE TREATMENT OF OSTEOLYTIC LESIONS AND BONE PAIN IN PATIENTS WITH BONE METASTASES ASSOCIATED WITH BREAST-CANCER

Survival of tumour cells in bone metastases is thought to be enhanced through complex relationships with osteoblasts and osteoclasts. Bispho sphonates are already proven to be efficacious in the treatment of hyp ercalcaemia of malignancy, and in vitro work suggests that they disrup t osteoclast function either through a direct action on osteoclasts, r educing the number of mature functioning osteoclasts formed, or by dis rupting the signalling that occurs between osteoblasts and osteoclasts . Tumour cells in bone are also thought to affect signalling between o steoblasts and osteoclasts through the production of parathyroid hormo ne-related protein and other cytokines. In vivo work has shown that bi sphosphonates can reduce the tumour burden in bone in an animal model, and clinical studies have shown that regular treatment with pamidrona te can reduce the number of complications from bone metastases in wome n with breast cancer, as well as increasing the length of time until t he first complication occurs. Beneficial effects are also seen in term s of pain reduction, reduced risk of pathological fractures, and enhan ced quality of life. Both oral and intravenous pamidronate produce the rapeutic benefits, though adverse gastrointestinal effects limit the u sefulness of the oral administration route. There is no evidence to sh ow that pamidronate increases survival or prevents the development of metastases.