Tumor-induced osteolysis due to breast carcinoma and myeloma is responsible for a considerable morbidity that severely impairs patients'quality of life. Osteoclast-mediated bone resorption is reported to be increased markedly in patients with tumor bone disease and can be inhibited by bisphosphonate therapy.
The incidence of skeletal complications and the effectiveness of bisphosphonate therapy in patients with breast carcinoma metastatic to bone or in those with myeloma were derived from large-scale, long-term, placebo-controlled trials with clodronate or pamidronate. To the authors' knowledge, there are few studies published to date evaluating the cost-effectiveness of bisphosphonate therapy, and the majority that do exist often are based on models and are applicable only to a particular health care system.
From the placebo groups of the above-mentioned trials, one can estimate that approximately 25-40% of the patients with breast carcinoma metastatic to bone will require radiotherapy for bone pain and approximately 17-50% will sustain incident vertebral fractures yearly. The incidence of complications is reported to be lower in myeloma patients. The prolonged administration of bisphosphonates reportedly can reduce the frequency of skeletal-related events by approximately 25-50%. Maximal efficacy appears to have been achieved with the current therapeutic schemes based on monthly intravenous infusions. Beneficial effects appear to be obtained more readily using the intravenous route rather than the oral route. The costs of bisphosphonate therapy appear to be higher than the cost savings from the prevention of skeletal-related events. The costs per quality of life-adjusted year have been estimated to be > $100,000, but more research is needed. Limited data suggest that zoledronic acid will not reduce treatment costs but the short infusion time will lead to substantial time savings for patients and for outpatient oncology facilities.
As is the case for many agents used in oncology, bisphosphonates remain a relatively expensive therapy. More studies are needed to evaluate their cost-effectiveness ratio correctly. A ceiling effect has been reached with current therapeutic schemes and tailoring therapy to the individual patient needs to be evaluated correctly to increase therapeutic effectiveness and improve quality of life further without increasing treatment costs.