Abstract
INTRODUCTION: Serum tumor markers have emerged as an effective tool to determine prognosis and treatment efficiency in different cancer types. This study aimed to explore the chemotherapy monitoring efficiency and prognostic sensitivity of tumor-associated cancer antigen 15-3 (CA 15-3) and carcinoembryonic antigen (CEA) in early (II) and late (IV) clinical stage breast cancer. METHODS: CA 15-3 and CEA serum levels were assessed in 56 breast cancer patients at early (n = 26) and late (n = 30) clinical stages with these primary inclusion criteria: those who received adjuvant chemotherapy AC (adriamycin and cyclophosphamide) or AC-T (adriamycin and cyclophosphamide followed by taxane) regimens and possessed tumors negative for human epidermal growth factor receptor 2 (HER2) based on a particle-enhanced turbidimetric assay. RESULTS: CA 15-3 had a higher elevation than CEA in the pretreatment group of breast cancer patients when compared to healthy controls. Late-stage patients showed higher positive serum levels than early-stage patients for both markers, with a preference for CA 15-3 over CEA. AC-T chemotherapy regimen treatment in both clinical stages revealed a significantly higher level of both markers as compared to the AC regime, with a preference for CA 15-3 over CEA in late stage. Both markers were significantly higher in the late-stage group as compared to early-stage groups for both chemotherapy regimens. CONCLUSIONS: CA 15-3 is more efficient as a prognostic monitoring marker than CEA and reveals a positive connection between chemotherapy regimen system and staging, with increased observability in late-stage patients.