The skeleton is a common site for the spread of metastatic
cancer and skeletal complications are a cause of significant morbidity and mortality. Treatment of skeletal morbidity is therefore an essential component of
therapy for
cancer patients with bone
metastases.
Bisphosphonates are currently the treatment of choice for skeletal complications. In a patient diagnosed with bone
metastases, skeletal morbidity is evaluated by a number of endpoints known as skeletal related events. These include bone
pain, requirement for radiation or surgery to bone, pathologic and radiologic fractures,
hypercalcemia, and progression of bone
metastases. The efficacy of
bisphosphonate treatment is evaluated by their effect on the number and frequency of skeletal-related events. In addition,
surrogate markers of
bone resorption such as
collagen telopeptides or quality of life measurements can be used to monitor
therapy, though these do not necessarily reflect skeletal morbidity. Intravenous
pamidronate is currently the standard treatment for patients with bone
metastases, and is effective in reducing the frequency of a variety of skeletal-related events. The more potent
bisphosphonates ibandronate and
zoledronate are now being evaluated in this setting. These agents may offer advantages over
pamidronate in terms of convenience of administration. Clinical trials underway will determine whether they are equivalent or even superior to
pamidronate in reducing skeletal-related events.