Background: Neoadjuvant chemotherapy (NAC) with taxanes followed by fluorouracil, epirubicin, and cyclophosphamide (FEC), and concurrent trastuzumab is a potent regimen for HER2 over-expressing breast cancer. A high pathological complete response (pCR) rate has been achieved using this regimen; however, the predictive factors and prognostic effects of pCR currently remain unclear. In the present study, we determined whether pCR was related to histological grade (HG) and several biological factors including p27(Kip1). We also assessed the prognosis of the pCR and non-pCR groups, and expected differences between those positive and negative for lymph node metastasis after chemotherapy.
Methods: A total of 129 Japanese women with HER2-positive invasive breast cancer received either paclitaxel or docetaxel followed by FEC, with the concomitant administration of trastuzumab. The statuses of HG, ER, PgR, Ki67, and p27(Kip1) were evaluated to determine their relationship with pCR. Relapse-free survival (RFS) and overall survival (OS) were also analyzed for their relationship with pCR and pathological nodal involvement.
Results: pCR was obtained in 84 out of 129 patients and the pCR rate was 65.1%. The pCR rates related to 5 factors were as follows: HG (grade 3, 70.0% vs. grades 1-2, 36.8%), ER (negative, 78.6% vs. positive, 40.0%), PgR (negative, 75.3% vs. positive, 38.9%), Ki67 (high, 72.0% vs. low, 47.2%), and p27(Kip1) (low, 71.0% vs. high, 50.0%). RFS was significantly better in the pCR group than in the non-pCR group (p = 0.018). Patients with remaining nodal disease in the pCR group had worse OS (p = 0.0002).
Conclusions: High-HG, low-ER, low-PgR, high-Ki67, and low-p27(Kip1) were identified as predictive factors of pCR in NAC with trastuzumab, while pCR and negative nodes were predictive of better survivals.