Dear Natia, The goal of treatment for metastatic breast cancer is control of the disease and symptoms. Treatment can be approached from many angles. One method is through the use of various chemotherapy medications, such as Taxol, or combinations that are given for earlier stage disease (Cytoxan, methotrexate or adriamycin/epirubicin, 5-fluorouracil). Hormonal manipulation may be especially useful for those with predominately bone metastasis. Aromatase inhibitors such as Arimidex are also used. The monoclonal antibody Herceptin, is also used in patients whose tumors overexpress HER2 protein receptors. The use of these treatments and the order and/or combinations in which they are used varies.
Bone metastases secrete substances that can cause cells, called osteoclasts, to dissolve or “eat away” a portion of the bone. These lesions weaken the bone and can lead to complications. Some of the complications are bone pain, fractures, and less commonly, calcium levels in the blood can become dangerously high as a result of the bone breakdown.
The drugs Aredia (pamidronate) and Zometa (Zoledronic Acid) are biphosphonates. Biphosphonate medications are used to slow down the osteoclast’s effects on the bone. In doing this it can be useful in slowing down or preventing the complications (bone pain, fractures, or high calcium levels) of the bone breakdown.
Studies have been done comparing these two medications in the treatment of bone metastases, in patients with breast cancer. The results showed that Zometa was as effective as Aredia in the treatment of bone metastases in patients with advanced breast cancer. Currently in the United States, Zometa is approved for treatment of hypercalcemia (another possible complication of cancer), and not yet approved for treatment of bone metastasis, unless given as part of a clinical trial.
I’ve not heard of the medication Klondronat, perhaps it is misspelled, but it doesn’t bring any specific therapies to mind.
Radiotherapy is used as localized treatment to bone lesions for symptom control (pain). It can also be considered to help to prevent fractures depending on how much of the bone is involved.