Abstract
Aims: Breast carcinomas in locally advanced cases are usually treated with neoadjuvant chemotherapy(NACT). Now adays it is also extended to some cases of early and operable breast cancer cases also.The aim of the study is to highlight the histopathological changes observed after neoadjuvant chemotherapy breast cancer specimens and to evaluate the role of histopathological examination in assessing the complete response (pCR), pathological partial response (pPR) and pathological no response(pNR).
Methods: A retrospective one year study carried out in our tertiary care cancer centre from January 2019 to December 2019. Pathological response to NACT were assessed in terms of the residual tumour size, histological grade, lymphovascular space invasion, fibrosis, calcification , histiocytes and the necrosis. Pathological response was calculated by the residual cancer burden(RCB) and the tumour node metastases (ypTNM) staging system was determined by the 8th edition of AJCC(American joint cancer committee) staging guidelines.
Results: A total of 143 breast cancer patients treated with NACT followed by surgery were included. Of the 143 cases of post NACT ,115 cases had residual cancer(80.41% ) and 28 cases(19.5%) showed complete pathological response. Grossly(macroscopically) the tumour was identifiable in 68% of cases. Histologically,most of the residual carcinomas post NACT were invasive ductal carcinoma of no special type. About 70 cases (48.95%) of the post NACT breast cancer patients were of grade 2. Necrosis was noted in 41.2% (59out of 143 cases) .98 cases(68%) showed lymphnode metastasis. pCR was seen in 19.5% of cases, pPR was noted in 74.12% of cases and 6.29% were pNR.
Conclusions: NACT followed by surgery is a treatment modality in management of locally advanced breast cancer. It is now also promising treatment strategy which can be extended for the management of early stage and in operable breast cancers. This study focuses on the easily reproducible histopathological parameters and their inclusion in the histopathology report. Histopathological evaluation can predict the response to chemotherapy and can impact the further course of treatment.

Key words: Breast cancer, Neoadjuvant chemotherapy, pathological evaluation, pathologic complete response