Clinicopathological Characteristics of Triple-negative Breast Cancers in the Northeast Region of Turkey

Background: Triple-negative (TN) breast cancer is a subtype of breast cancer characterised by a loss of estrogen receptor (ER), progesterone receptor (PR) expression, and the absence of human epidermal growth factor (HER2) overexpression. Aims: To identify the relationships between clinicopathological characteristics of TN breast cancers in the northeast region of Turkey and disease free survival (DFS) and overall survival (OS). Study Design: Retrospective clinical study. Methods: Seven hundred and eighty non-metastatic breast cancer patients were enrolled in this study. The relationships between TN breast cancer and other breast cancers with respect to clinicopathological characteristics, as well as DFS and OS, were studied. Results: The triple-negative phenotype was detected in 204 patients (27.1%). Patients with triple-negative breast cancer had more grade 2-3 tumours compared to those with other types of breast cancer (92.5% versus 84.3%, p=0.004). Invasive ductal carcinoma histology, on the other hand, was less prevalent in patients with TN breast cancer (77% versus 84.5%, p=0.016). No significant differences were identified between the groups in other clinicopathological variables. Relapse and mortality rates were higher in the TN group during the follow-up of both groups [57 (27.9%) versus 89 (16.2%), p<0.001 for relapse; 27 (13.2%) versus 37 (6.8%), p=0.005 for mortality]. The univariate analysis demonstrated shorter DFS and OS for patients with TN breast cancer compared to those with other types of breast cancer. In the multivariate analysis, patients with TN breast cancer were 2.21 times more likely to develop relapse, while the likelihood of death increased 3.21-fold (p<0.001 and p