Chemotherapy Unlike many other epithelial malignancies, breast cancer responds to multiple chemotherapeutic agents, including anthracyclines, alkylating agents, taxanes, and antimetabolites. Multiple combinations of these agents have been found to improve response rates somewhat, but they have had little effect on duration of response or survival. The choice among multidrug combinations frequently depends on whether adjuvant chemotherapy was administered and, if so, what type. While patients treated with adjuvant regimens such as cyclophosphamide, methotrexate, and fluorouracil (CMF regimens) may subsequently respond to the same combination in the metastatic disease setting, most oncologists use drugs to which the patients have not. | Chapter 086. Breast Cancer Part 11 Chemotherapy Unlike many other epithelial malignancies breast cancer responds to multiple chemotherapeutic agents including anthracyclines alkylating agents taxanes and antimetabolites. Multiple combinations of these agents have been found to improve response rates somewhat but they have had little effect on duration of response or survival. The choice among multidrug combinations frequently depends on whether adjuvant chemotherapy was administered and if so what type. While patients treated with adjuvant regimens such as cyclophosphamide methotrexate and fluorouracil CMF regimens may subsequently respond to the same combination in the metastatic disease setting most oncologists use drugs to which the patients have not been previously exposed. Once patients have progressed after combination drug therapy it is most common to treat them with single agents. Given the significant toxicity of most drugs the use of a single effective agent will minimize toxicity by sparing the patient exposure to drugs that would be of little value. No method to select the drugs most efficacious for a given patient has been demonstrated to be useful. Most oncologists use either an anthracycline or paclitaxel following failure with the initial regimen. However the choice has to be balanced with individual needs. One randomized study has suggested docetaxel may be superior to paclitaxel. A nanoparticle formulation of paclitaxel abraxane has also shown promise. The use of a humanized antibody to erbB2 trastuzumab Herceptin combined with paclitaxel can improve response rate and survival for women whose metastatic tumors overexpress erbB2. The magnitude of the survival extension is modest in patients with metastatic disease. Similarly the use of bevacizumab avastin has improved the response rate and response duration to paclitaxel. Objective responses in previously treated patients may also be seen with gemcitabine capecitabine navelbine and oral etoposide.
