Comparison of tumor size, histopathological grade, and molecular subtype of breast cancer at a single center study.

Background: Breast cancer (BC) is the second most frequent cancer-related death among women worldwide. Factors influencing BC patients' survival include histopathological grade, histopathological type, stage, hormonal receptors, and number of mitotic images.

Objective: To compare the tumor size, histopathological grade, and molecular type of BC patients.

Methods: This was an observational analytic retrospective study. The population was BC patients at Dr. Wahidin Sudirohusodo Hospital from 2017 to 2021. The Kruskal-Wallis test was used to compare statistically between tumor size, histopathological grade, and molecular subtype. Significance was set at p < 0.05.

Results: The study included 784 patients. Most were aged 50-59 years (34.8%), with tumor size 4c (37.0%) and moderate grade (66.1%), and the most common molecular subtype was luminal A (34.2%). Bivariate analysis using the Kruskal-Wallis test found no significant difference in molecular subtypes based on tumor size (p = 0.079), but significant differences existed in molecular subtype by histopathological grade (p = 0.005) and tumor size by histopathological grade (p < 0.001).

Conclusions: Significant differences existed between histopathological grade by tumor size and molecular subtype. Early diagnosis and prompt treatment of BC patients are important to prevent morbidity and mortality.