How effective is chemotherapy for treating breast cancer?

Very effective: Chemo initially started with combinations like CMF and then changed to combinations of antibody plus chemo such as taxol plus Herceptin (trastuzumab). These drugs alone and in combination best used as a neoadjuvant prior to surgical resection or when at high risk in the adjuvant setting to prevent recurrence. Once metastasis happens, there can be chemo control but cure is rare.