Assessment of clinical response after two cycles of primary chemotherapy in breast cancer

Background Complete clinical (cCR) and pathological (pCR) response to neoadjuvant chemotherapy in breast cancer is associated with improved survival. Various imaging and immunological techniques have been tested as predictors of response early in the course of chemotherapy, but their predictive value has not been compared with that of a simple early clinical assessment. Patients and methods Two hundred breast cancer patients (T2-4, N0-1) were treated with neoadjuvant chemotherapy. Clinical response after two cycles of treatment was compared with final clinical and pathological response. The likelihood of achieving cCR or pCR was compared by response after two cycles. Results Overall final clinical response rate was 79% (30.5% cCR and 11.9% pCR). After two cycles of chemotherapy, clinical response rate was 54.5%. For responders after two cycles, final cCR = 51.3% and pCR = 21.5%. For non-responders after two cycles, cCR = 5.5% and pCR = 1.2%. Response after two cycles predicts for pCR (P = 0.003; sensitivity 95.2%, specificity 52.9%). Conclusions Clinical response after two cycles of chemotherapy predicts for pCR and is a valid early end-point that could be incorporated into the design of future neoadjuvant trials.