Prognostic parameter differences in breast cancer patients between luminal A and luminal B types after application of the new classification according to Ki67 score

Abstract

BackgroundThe conventional histological classification of breast cancer doesn't provide sufficient information about the biological characteristics and treatment prediction for breast cancer subtypes. Luminal breast cancer has been classified recently according to the expression of ki67 which has a great impact of the biological activity of the tumor. Patients and methodsA total of 300 patients with breast cancer who underwent modified radical mastectomy were investigated. Patients were divided into 2 groups: Luminal A (101 patients) and B (199 patients) according to the new classification based on hormone receptor and Ki67 expressions and the prognostic parameters were investigated. ResultsThe mean age was 48.81 years with a mean BMI of 30.7, the age showed no significant correlation (P value 0.996), but it was significant with BMI (P value 0.045). Lobular breast cancer was commoner in luminal type-A (13.9%) comparing to type-B patients (5%) with a significant correlation with the histopathological type (P value 0.006). Most patients presented with clinical stage IIB, IIA, and IIIA respectively. The tumor size, axillary LN status, clinical stage, and recurrence or metastasis showed no statistical significance (P values 0.9, 0.078, 0.584, and 0.943) respectively, 66.3% of luminal type-A patients had intermediate grade and no tumor necrosis (72.5%), while 55.3% of luminal type-B patients had high grade and tumor necrosis (61.8%), the correlation was significant for tumor grade and necrosis (P values 0.000) for each parameter. Luminal type-B had higher breast cancer fatality rate compared to type-A (11.2% vs. 2%) with a significant correlation with survival status and duration of survival (P values 0.003 & 0.025) respectively. ConclusionLuminal type-A cancer is less common than type-B but has better survival and duration of survival than type-B. Ki67 biomarker affects tumor aggressiveness and invasiveness. More genetic analysis is required to detect the molecular diversity of both types.