Clinicopathological Profile of Invasive Breast Cancer Based on the Human Epidermal Growth Factor Receptor 2 (HER2) at Dr. Cipto Mangunkusumo Hospital from 2019-2020

Bahasa Inggris

Abstract

Introduction

Invasive breast cancer (IBC) is the most common malignancy in women. There are three groups of HER2-negative IBC which are HER2-null (score 0), HER2 ultra-low (score between 0 and 1+), and HER2-low (score of 1+ and 2+ without HER2 amplification). Recent studies on drugs for HER2-negative IBC suggest that the HER2-low and HER2 ultra-low groups with metastasis have the opportunity to receive new therapies, although the ultra-low group is still under investigation. Until now, studies on the three groups of HER2-negative IBC in Indonesia have been challenging to obtain. This retrospective study aims to assess the number of cases in the three groups of HER2-negative IBC and their clinicopathological characteristics at the Anatomical Pathology Department of Dr. Cipto Mangunkusumo Hospital during the years 2019-2020 and to evaluate the discrepancies in HER2 scores after reclassification.

Methods

This is a descriptive study with a cross-sectional design. The study utilizes secondary data from the Department of Anatomical Pathology archives of Dr. Cipto Mangunkusumo Hospital and its electronic medical records. Sample selection was done using consecutive sampling. Clinicopathological characteristics were recorded, and HER2 expression was reassessed and reclassified.

Results

A total of 1129 samples were obtained. The number of HER2-negative cases in the HER2-null group was 352 cases (31.3%), HER2 ultra-low was 214 cases (18.9%), and HER2-low was 563 cases (49.8%). The most common histopathological type of breast cancer and histological grade were no special type (NST) carcinoma and histological grade 2. The most common molecular subtype was luminal B HER2-negative.

Conclusion

HER2 status examination in breast cancer is useful for treatment. Pathologists are expected to distinguish between HER2 scores of 0 and 1+ and to include these in the examination report. This aims to assist clinicians in determining the appropriate therapy for patients.