Main prognostic and predictive immunohistochemical factors in breast cancer: a retrospective cohort study

Abstract

Introduction: Breast cancer is a constant focus of studies on prevention and treatment. Immunohistochemistry is a useful tool for defining the conducts toward the treatment of this disease. Objective: To evaluate patients' survival according to prognostic and predictive immunohistochemical factors. Method: This is a retrospective cohort study. Medical reports of 787 patients were analyzed, which contained parts of surgical specimens of the mastectomy or quadrantectomy procedures. A total of 404 patients were eligible for the study. Results: The mean age at diagnosis of the disease was 55.4 years. The main diagnosis was infiltrating ductal carcinoma (80.7%). Of the total, 45% of the patients had tumors of up to 2 cm in diameter, and 32.9% had lymph node involvement. Among the patients, and according to luminal molecular classification, 48.3% were classified as luminal A, 27% were luminal B, 12.1% were recipient of human epidermal growth factor type 2 (HER2), and 12.6% were triple-negative. Furthermore, of 23.3% patients with tumor recurrence, 12.6% of them died. The 1% increase in Ki-67 values increases the risk of death and recurrence by 2% and 1%, respectively. The presence of lymph node metastasis increases, on average, 4.78 times and 2.63 times the risk of death and recurrence, respectively. Conclusion: The triple negative molecular classification had the lowest overall survival and the greatest risk of recurrence. The luminal A classification presented the best prognosis. Tumor size, lymph node metastasis, skin invasion, and presence of Ki-67 were shown to be the prognostic and predictive factors that most influenced the patients' survival.