Response to neoadjuvant chemotherapy in locally advanced breast cancer according to tumor subtypes

To compare the pathological response to neoadjuvant chemotherapy in different molecular subtypes of breast cancer Study Design: Prospective cohort study. Place and Duration of Study: Department of Oncology Liaquat National Hospital Karachi from Jan 2013 to Dec 2014. Material and Methods: A total of 119 patients received neo-adjuvant chemotherapy for locally advanced breast cancer followed by definitive surgery. Demographic, clinical and pathological data of 101 patients were available for analysis. Tumors were divided into different molecular subtypes, luminal A, luminal B human epidermal growth factor receptor 2 (HER 2) was negative, luminal B (HER 2 positive), HER 2 over expressed and triple negative. Neoadjuvant chemotherapy was given for total of eight cycles. Primary end point was pathological response [pathological complete response (PCR) versus no PCR] after surgery. Results: A total of 101 patients data were analyzed. Seventeen (16.8%) were luminal A, thirty eight (37.6%) were luminal B, out of 38 luminal B patients, twenty one (55.2%) were HER 2 + and seventeen (44.7%) were HER 2 -ve. Sixteen (15.8%) patients were HER 2 over expressed and thirty (29.7%) were triple negative. Out of 101 patients, twenty eight (27.72%) achieved PCR. A total of 5.9% achieved PCR in luminal A, 4.8% had PCR in luminal B (HER 2 -ve type), 23.5% had in luminal B (HER 2 +ve type), 50% achieved PCR in HER-2 over expressed type and 46.7% had PCR in triple negative subtype, (p=0.001). There was no significant association of PCR with age, tumor size, lymph node status, histology or grade. Conclusion: Molecular subtypes of breat cancer were found to be statistically significant predictor of PCR after neoadjuvant chemotherapy. (author)