Impact of Neoadjuvant Chemotherapy on Immunohistochemistry Profile of Breast Carcinoma

Introduction- Management of Breast Carcinoma is multidisciplinary and has come a long way. Chemotherapy and Hormonal therapy decisions for breast cancer management are based on expression of tumour biomarkers: Estrogen Receptor (ER), Progesterone Receptor (PR), Human Epidermal Growth Receptor 2 (HER 2 neu) and Ki-67 index. The impact of Neoadjuvant Chemotherapy (NACT) on the immunohistochemical (IHC) profile remains controversial with wide variation in results across studies. To determine the Objectives- immunohistochemical changes in post Neoadjuvant Chemotherapy breast cancer specimens and to study the histopathological findings after NACT. A Materials and Methodscross sectional study was done using fifty-one (51) diagnosed cases of breast cancer after having received at least 4 cycles of NACT. Immunohistochemical study was done using monoclonal antibodies. The values of ER, PR, HER 2 neu & Ki-67 were evaluated & compared to preNACT scores. The histopathological findings were assessed. Statistical analysis was performed using MedCalc and Omni calculator. Associations between IHC markers before and after NACT were evaluated using the McNemars's test. Out of 51 cases Results- of breast carcinoma, majority (96.07%) were of Invasive Breast Carcinoma, no special type (IBC NST) and majority of the patients were in the age range of 41 to 50 years. 6 patients (11.76%) underwent pathological complete response. Change in HER 2 neu receptor expression post NACT was found to be statistically significant (p value- 0.016). There was an overall trend towards low Ki-67 observed after NACT which was also statistically significant (p value0.00004). The changes in ER & PR were not statistically significant. It was observed that biomarkers Conclusion- and histopathological response of breast cancer may change after NACT. Changes in HER 2 neu & Ki-67 expression were significant.