Clinicopathological Profiles of and Patterns of Recurrence in Triple-Negative Breast Cancer Patients at a Cancer Care Center in Southern India.

Abstract

Triple-negative breast cancer (TNBC) is characterized by the absence of expression of the estrogen receptor and the progesterone receptor by immunohistochemistry and human epidermal growth factor receptor overexpression absence either by immunohistochemistry or absence of amplification by fluorescence in-situ hybridization. TNBCs tend to have rapid growth when compared to other subtypes of breast cancer. TNBC is associated with higher histologic grade and more advanced disease at presentation. TNBC shows aggressive behavior and a high chance of recurrence. The aim was to analyze the clinicopathological profiles of and recurrence patterns in TNBC patients at our institute where most patients are from rural areas. This retrospective study was done at a tertiary cancer care center in Southern India where most patients come from rural backgrounds. Institutional Ethics Committee approval was obtained before the study. Case files of all breast cancer patients registered and treated at our center from 2014 to 2019 were retrieved from the medical record department and reviewed. Data from patients diagnosed with triple-negative breast cancer were identified and analyzed. Among the 841 breast cancer patients registered in our study, 150 (17.8%) were diagnosed with TNBC. The median age of diagnosis was 47 years. The majority of the patients, 89 (59.3%) presented with T2 tumors, and lymph node involvement was observed in 88 (58.6%) cases. Patient distribution based on cancer stage revealed that 77 (51.3%) had early-stage breast cancer (EBC), 70 (46.6%) had locally advanced breast cancer (LABC), and only three patients were categorized as having metastatic breast cancer (MBC). Modified radical mastectomy (MRM) was the preferred surgical approach in 144 (96%) cases, while only four patients underwent breast-conserving surgery (BCS). Adjuvant chemotherapy was administered to 119 (79.3%) patients, with 30 (20%) receiving both neoadjuvant and adjuvant chemotherapy (NACT/ACT). Among those who underwent NACT/ACT, a pathological complete response was observed in five (16.6%) patients out of 30 patients. The median duration of follow-up was 32.8 months. Among all patients, 36 (24%) experienced recurrence, with seven (19.4%) having local recurrence, 24 (66.6%) developing distant metastases, two patients experiencing both local and distant recurrence, and three patients developing contralateral breast cancer. Additionally, three patients experienced a second primary cancer. The most common sites of metastases were the lungs (14), followed by the bone (seven), the liver (four), and the brain (four). Recurrence rates were notably high within the first one to three years post-diagnosis. The median disease-free survival (DFS) of TNBC patients was estimated to be 65.6 months with no statistically significant difference (p=0.174) between EBC and LABC patients. TNBC is known for its heterogeneity. While it is often regarded as being more responsive to chemotherapy compared to other subtypes of breast cancer, TNBCs tend to behave aggressively, basically due to the underlying aggressive tumor biology. Though there are many treatment options for different subtypes of breast cancer, therapeutic modalities are limited for TNBCs. Aggressive tumor biology with limited treatment options denotes a gap in the development of novel strategies to improve outcomes in this subset of breast cancer patients.