Neoadjuvant breast cancer: statistical and histopathological analysis of tumor response. Casuistry of the National Hospital of Clinics

Abstract

Breast cancer is a quite prevalent neoplasm in the world, and its treatment has been changing, one of the fundamental pillars being neoadjuvant treatment. It consists of chemotherapy treatment that is administered to reduce the size of the tumor before surgical treatment, thus enhancing the effectiveness of surgery and reducing the tumor stage and the likelihood of dissemination or recurrence. The aim of this study is to evaluate the tumor response to neoadjuvant treatment in breast carcinoma surgical specimens removed at the HNC over a period of 46 months, exploring the possible relationship with different histopathological variables and analyzing epidemiological aspects of this pathology in our hospital.

An observational, descriptive, retrospective and cross-sectional study was performed, with nonprobabilistic sampling by convenience, analyzing anatomopathological reports of surgical pieces of quadrantectomies and mastectomies referred to the Anatomic Pathology Service of the HNC, in the period between June 1, 2019 and April 1, 2023, with a diagnosis of invasive carcinoma with previous neoadjuvant therapy. The sample n was 56. The following variables were analyzed: age, laterality, histologic type, histologic grade, molecular subtype, previous tumor size, tumor response grade (Myller and Payne System).

The results showed that the overall response to neoadjuvant therapy was intermediate (MYP 3); the highest percentage of complete response (MYP5) was seen in triple negative (TN) tumors, with histological grades Nottingham 3; left-sided tumors had more complete remission; histological type without differences; previous tumor size and age without significant findings.

Conclusion is that bibliography consulted coincides in relation to most of the variables analyzed, as for instance general distribution of the response grades to neoadyuvancy, and also regarding histological grades 3 and TN subtypes,considered as predicting factors of complete pathological response. Nevertheless an unexpected finding has to do with laterality where it was found that left sided tumors had a greater rate of complete remission contrary to what was described in said bibliography.