[Bisphosphonates in adjuvant therapy of breast cancer].

Abstract

For more than 10 years, based on the results with the bisphosphonate clodronic acid, it has been discussed, whether the occurrence of breast cancer metastases can be avoided or at least delayed by administration of bisphosphonates. The published results of recent studies applying, e.g., the bisphosphonates zoledronic and ibandronic acid, respectively, seem promising at first glance, especially, if the therapeutic acceptance of bisphosphonates in the indications osteoporosis and bone-related complications of malignancies, respectively, as well as their spectrum of side effects are taken into account and their putative mechanism of action is considered. There is a broad consensus that the existing data basis suffices to demonstrate importance of bisphosphonates in an adjuvant therapeutic setting of breast cancer. Significant relative risk reductions of, e.g., 36% in disease-free survival are very impressing and the corresponding absolute values of 3.2% are second-line communications. However, evaluation of all studies published so far according to the criteria of evidence-based medicine demonstrates many open questions and several methodical insufficiencies. Therefore, effectiveness and benefit of an adjuvant therapeutic application of bisphosphonates in breast cancer patients cannot be drawn out of evidence-based data. A recommendation of this therapy is given only by the German Working Pool of Gynecologic Oncology (AGO), but limited to study participation.