Neoadjuvant Therapy in Clinical Stage I-III HER2-positive Breast Cancer.

Neoadjuvant therapy is given to breast cancer patients whose cancers are relatively large or have spread to lymph nodes or both. The primary goal of this treatment is to prevent the cancer from coming back (recurring) elsewhere in the body, but if it makes the cancer in the breast and lymph nodes shrink it might be easier to remove. This could allow a patient to have a lumpectomy instead of a mastectomy and reduce the number of lymph nodes that the surgeon has to remove. In some cases, the neoadjuvant therapy works so well that it kills all of the cancer in the breast and lymph nodes. This is referred to as a pathologic complete response (pCR). Patients who achieve a pCR have a much lower risk of the cancer recurring elsewhere in their bodies. Investigators aren't sure which chemotherapy drugs work best with the HER2-targeted drugs, and what combination of these drugs causes the fewest side effects.Thus, this study has two main goals: 1. To find out if treatment with wPCbTP, weekly paclitaxel and carboplatin given with trastuzumab and pertuzumab every 3 weeks, leads to as many pCRs as TCHP in patients with HER2-positive breast cancer, but has fewer side effects. 2. To find out if HER2-positive patients whose cancers are not responding well after 12 weeks of wPCbTP get a better response when they are switched to a doxorubicin-containing regimen called AC for 4 cycles (8-12 weeks).

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