Clinicopathological characteristics and endocrine therapy resistance status of premenopausal luminal B-like HER2 negative breast cancer in Hasan Sadikin Hospital Bandung

Abstract

Introduction
Luminal B-like HER2 negative is the most common molecular subtype of breast cancer in Indonesia and endocrine therapy is one of the treatment strategies. This study intended to describe the clinicopathological characteristics and endocrine therapy resistance status of premenopausal luminal B-like HER2 negative breast cancer in Dr. Hasan Sadikin General Hospital Bandung.

Methods
This retrospective study included premenopausal luminal B-like HER2 negative breast cancer who received endocrine therapy in Dr. Hasan Sadikin General Hospital from 2018-2024. Subjects were categorised as resistant and nonresistant group. Clinicopathological characteristics were analysed, including age, tumor size, lymph node metastasis status, histopathological type and grade, clinical stadium at diagnosis, and Miller-Payne status.

Results
A total of 105 cases were collected. The mean age at diagnosis was 43.3 years (SD ± 5.8 years). Most of the cases had T3 tumor size (85.7%) and pN0 lymph node metastasis status (49.5%), concluded as stage IIB at diagnosis (42.9%). The majority cases were invasive breast carcinoma of no special type (IBC-NST, 82.9%) and histopathological grade 3 (46.7%). When comparing the resistant and nonresistant group, histopathological type, histopathological grade, and Miller-Payne status has shown a statistically significance differences (p = 0.014, p = 0.040 and p = 0.002, respectively).

Conclusion
In conclusion, premenopausal luminal B-like HER2 negative breast cancer cases at Hasan Sadikin Hospital predominantly present with advanced tumor size (T3) and stage IIB. Significant associations were found between endocrine therapy resistance and factors such as histopathological type, grade, and Miller-Payne status, highlighting the need for targeted therapies to address resistance in this population.