To determine the complete pathological response rate after neoadjuvant chemotherapy in breast cancer

Background: In breast cancer after administration of NACT ultimately negative results for residual cancer is defined as pathological complete response (pCR). Patients with subtype; positive for low-grade estrogen receptor (ER) and negative human epidermal growth factor receptor 2 (HER2), have poor survival rate.
Objective: To determine the complete pathological response rate after neoadjuvant chemotherapy in breast cancers patients at a tertiary care hospital.
Material and Methods: This prospective cohort study was conducted at Department of Medical Oncology Jinnah Postgraduate Medical Center, Karachi from June 2016 to June 2017. All patients received injection Doxorubicin 60mg/m2 IV day 1 and Cyclophosphamide 600mg/m2 IV on day1. Cycle repeated every 21 days for 4 cycles, followed by injection Paclitaxel 80mg/m2 via 1-hour IV infusion weekly for 12 weeks, followed by surgery. During chemotherapy patients were followed up to manage any adverse effect of chemotherapy. Descriptive statistics were calculated. Chi square test were applied to see the association of outcome.
Results: There were significant response observed with high rate of complete response (n=16, 61.5%) in patients with T3 stage of breast cancer. Complete response was similar in ER and PR positive patients that is 29%. Similarly, response to therapy coincided in ER and PR negative patients that is 27%. Complete response was higher (34%) in HER2 patients while in HER2 negative showed in 26%, with no statistically significance (p-value= 0.45).
Conclusion: NACT in breast cancer reduce the tumor burden and considerably good therapeutic option to achieve the complete pathological response. In our study we found that complete pathological response rate of 31.3% after NACT in locally advanced breast cancer.