Abstract
INTRODUCTION: Breast cancer is among the most prevalent cancers in women globally, with patients' survival adversely impacted by Ki67 expression and triple-negative phenotypes. In this study, we examined the relationship between HER2/neu, triple-negative, and Ki67 phenotypes and tumor aggressiveness along with the survival of breast cancer patients from India. MATERIALS AND METHODS: A retrospective cohort study was performed using hospital-based data from a tertiary care center spanning January 2013 to August 2023. The study included breast cancer patients who received neoadjuvant chemotherapy based on preoperative assessment and/or adjuvant chemotherapy following postoperative evaluation. Patients with other primary cancers or those treated with investigational drugs were excluded. Data on variables such as age, parity, menopause, cancer stage and grade, estrogen receptor (ER), progesterone receptor (PR), HER2/neu, Ki67 score, and the use of biologicals, hormones, and chemoradiotherapy were analyzed using correlation and regression tests to identify factors associated with aggressive tumor behavior. Kaplan-Meier survival model and Cox-proportional hazard test were applied. RESULTS: A total of 389 breast cancer patients with a mean age of 54.3 years met the eligibility criteria and were included in the analysis. A higher prevalence of hormone receptor positivity was observed among Indian patients than in Western countries. Younger, premenopausal women were more likely to present with high-grade tumors and high Ki67 scores, poorer overall survival, and the need for chemoradiotherapy. On the other hand, nulliparous patients mostly had triple-negative tumors with high Ki67 scores. Aggressive tumor behavior was linked to HER2/neu positivity, ER and PR negativity, and the requirement for both neoadjuvant and adjuvant chemotherapy. At the same time, premenopausal patients more frequently were candidates for radiation therapy. HER2/neu expression demonstrated a moderate negative correlation with co-expression of hormone receptors (ER and PR). Cancer grade was associated with Ki67 levels, nulliparity, triple-negative status, and hormone receptor expressions (ER and PR). Median survival was not reached for the study cohort. CONCLUSION: Tumor aggressiveness was associated with a high Ki67 score, HER2/neu positivity, and the absence of hormone receptor expression in patients.