NeoMET Study in Neoadjuvant Treatment of Breast Cancer

Neoadjuvant therapy is the standard treatment for locally advanced breast cancer and has adopted in early breast cancer treatment. A meta-analysis showed no difference between neoadjuvant therapy and adjuvant therapy in terms of survival and overall disease progression. Therefore, neoadjuvant treatment can be offered as a standard treatment and as an alternative to adjuvant treatment to all patients who are expected to be candidates for adjuvant systemic chemotherapy. Patients achieved pCR after treatment have superior outcome. The taxanes were introduced into clinical practice in the early 1990s, and recent meta-analysis showed that compared with anthracycline-containing chemotherapy, taxanes-containing regimens significantly reduced the annual breast cancer recurrences and deaths. Right now, TAC regimen has widely accepted as adjuvant or neoadjuvant chemotherapy regimens in breast cancer treatment. Metformin, an inexpensive oral agent commonly used to treat type 2 diabetes, has been garnering increasing attention as a potential anti-cancer agent. In neoadjuvant treatment of breast cancer, a retrospective clinical study from MDACC reported a significantly increased pCR rates to standard neoadjuvant chemotherapy in diabetic breast cancer patients who were receiving metformin (24% pCR) compared to diabetics not receiving metformin (8% pCR), with intermediate rates in non-diabetics who did not receive metformin (16% pCR), indicating metformin may increase pCR rate with neoadjuvant chemotherapy. Base on these data, we initiate a prospective study to evaluate docetaxel, epirubicin and cyclophosphomide (TEC) with TEC plus metformin in neoadjuvant treatment of breast cancer patients. Our aim is to evaluate whether metformin can increase the pCR rate combination with TEC regimen in neoadjuvant setting.