Jean-Jac Body - Tumor Bone Diseases and Osteoporosis in Cancer Patients: Pathophysiology, Diagnosis, and Therapy

More than 100,000 new cases are now diagnosed per year in the United States, making it the second leading cause of cancer death in men. Of these advanced cases, at least 90% will involve bone metastases during their clinical course.

Adequate symptom evaluation and measurement of tumor markers and biochemical parameters of bone turnover should be more thoroughly investigated for early assessment of bone response after systemic therapy. Local radiotherapy still has an essential place in the management of painful metastatic bone disease. Pain relief can be obtained in more than half of the patients, but uncertainty remains as to the relationship between radiotherapy dose or fractionation and the incidence/duration of pain relief. More recently, radioactive isotopes have also been used quite successfully in patients with blastic bone metastases.

Increased osteoclast activity causes local foci of osteolysis, which could further stimulate cancer cell proliferation, just as products of bone resorption can enhance tumor cell growth. These data indicate that it is rational to target bone-resorbing cells for the treatment and prevention of tumor-induced osteolysis.

The effects are particularly marked for the incidence of hypercalcemic episodes, the number of fractures, and the need for radiotherapy. Iterative bisphosphonate infusions for I to 2 years can also prolong the median time to progression in bone and reduce the mean skeletal morbidity rate by up to 40%. Bisphosphonates are of even greater benefit to patients suffering from multiple myeloma, which is typically characterized by a marked increase in osteoclast activity and proliferation, a phenomenon that could by itself play a contributory role in the growth of myeloma cells in bone. Bisphosphonate treatment should now be part of the standard therapy for patients with multiple myeloma and at least one osteolytic lesion.