Meme Kanseri Tanılı Neoadjuvan Kemoterapi Tedavisi Alan Olguların Klinik, Patolojik Ve Radyolojik Özelliklerinin Retrospektif Olarak Değerlendirilmesi

Abstract

Breast cancer is one of the leading causes of morbidity and mortality among women worldwide. As a heterogeneous disease, treatment decisions are tailored based on patient and disease characteristics. Neoadjuvant chemotherapy is now considered a standard treatment approach for breast cancer. Pathologic complete response (pCR) after neoadjuvant treatment is a marker that provides predictive information for disease prognosis and survival. In this study, we aimed to evaluate the neoadjuvant treatment regimens, treatment doses, response rates to neoadjuvant treatment, factors predicting pCR and disease-free survival (DFS) times, and variables that may influence disease-free survival across different molecular subtypes of breast cancer. Materials and Methods: A total of 177 female patients diagnosed with breast cancer and treated with neoadjuvant chemotherapy at Hacettepe University Medical Oncology Department between 2012 and 2023 were included in the study. The cohort comprised 54 patients (30,5%) with hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative breast cancer, 92 patients (52,0%) with HER2 (+) breast cancer, and 31 patients (17,5%) with triple-negative breast cancer (TNBC). Demographic data, neoadjuvant treatment protocols, and histopathological tumor characteristics were retrospectively obtained from the hospital database. The analyses in the study were performed using SPSS Version 26 and p <0,05 was considered statistically significant. Results: The overall pCR rate in the cohort was 40.7% (n=72/177). The pCR rates were 9.3% in HR(+)/HER2(-) breast cancer, 52.2% in HER2(+) breast cancer, and 58,0% in TNBC. A significant association was found between molecular subtype and pCR (p=0.00). HR negativity was associated with a higher likelihood of achieving pCR in the overall cohort and the HER2(+) subgroup (p=0.00).Additionally, patients with a Ki-67 index ≥20% exhibited a significantly higher pCR rate than those with a Ki-67 index <20% (p=0.008). In both the overall cohort and TNBC subgroup, a stromal tumor-infiltrating lymphocyte (sTIL) level ≥30 was linked to an increased pCR rate. Furthermore, in the iv entire cohort and HER2(+) subgroup, patients treated with dose-dense doxorubicin (A)–cyclophosphamide (C) had a significantly higher pCR rate compared to those receiving standard-dose AC (p=0.011 and p=0.018, respectively). Among HER2(+) patients, dual anti-HER2 therapy resulted in a significantly higher pCR rate than single-agent anti-HER2 therapy (p=0.046). Patients who achieved pCR had significantly longer DFS (p=0.014). In patients without pCR, increasing residual tumor size was associated with shorter DFS (p=0.00). Additionally, DFS was significantly prolonged in patients without lymph node involvement after neoadjuvant therapy (p=0.00). Conclusion: Our findings align with existing literature regarding predictors of pCR, demonstrating that Ki-67 index, hormone receptor status, and TIL levels are significant predictors of treatment response. The dose-dense AC neoadjuvant chemotherapy regimen resulted in a higher pCR rate compared to the standard-dose AC regimen, though further studies are needed to confirm this finding.