The success of the bisphosphonates was in their ability to prevent tumors from dissolving bone thus stopping the cancers use of the byproducts of bone resorption. Cancer cells stimulate bone destruction which in turn releases cytokines or growth factors that stimulate cancer cell activity and growth. Bisphosphonates interrupt that activity, slowing metastatic bone cancer growth and spread and causing cell death of some cancer cells. In multiple myeloma, tumor deposits stimulate IL-6 production and other factors to increase bone resorption. PTH-rP in animals and has a synergistic effect when used with bisphosphonates in reducing tumor growth in mice .
Osteoblastic tumors are most evident in prostate cancer.
The effectiveness of bisphosphonates in reducing pain, and markers of bone destruction were confirmed by other researchers in the U.S. and England. Reports of newer, more potent bisphosphonates were available from researchers in Europe. The more powerful the drug, the less that was needed for infusion and the more dramatic and long lasting were the effects. There was general agreement among the researchers that the more potent the dose, the earlier that the patient began bisphosphonate therapy, the better the outcome. A 2 mg infusion of Zolendronate was more effective than 90 mg of Pamidronate in reducing pain and markers related to bone destruction and tumor growth.