Results response of neoadjuvant chemotherapy for stage III breast carcinoma at Viet Nam National Cancer Hospital

Objective: To characterize the clinical and paraclinical features of stage III breast carcinoma (BC) and evaluate the response to neoadjuvant chemotherapy (NAC). Methods: A cross-sectional study was conducted on 108 patients diagnosed with stage III breast cancer, who were treated with NAC, consisting of four cycles of Doxorubicin and Cyclophosphamide (4AC), followed by four cycles of Paclitaxel (4T). Results: The average age of the patients was 45.16 +/- 9.98 years (median age: 45 years), ranging from 29 to 66 years. According to the AJCC's 8 th edition (2017), the majority of patients were classified as stage IIIA (37.96%) and IIIB (38.89%), while 23.15% were in stage IIIC. Molecular subtypes included Luminal B in 60.66% of patients, HER2-positive in 42.59%, and triple-negative in 24.59%. The clinical response rate (based on RECIST 1.1 criteria) was 94.44% after four NAC cycles and improved to 97.22% after eight cycles. Histopathological assessment using the Chevallier classification showed a pathological complete response (pCR) rate of 29.63% and a near-complete response rate of 6.48%, with a residual disease (RD) rate of 63.89%. Conclusion: The study revealed that stage III breast carcinoma predominantly affects women around the age of 45 (66.67% were under 50 years), with stage IIIB being the most common. Luminal B was the most prevalent molecular subtype, while HER2 positivity was high, accounting for 40.98%. The dose-dense NAC regimen (2-week cycles) of 4AC-4T demonstrated high efficacy, with over 97% of patients achieving a clinical response after eight cycles, based on RECIST 1.1 criteria. The pathological complete response (pCR) rate, according to the Chevallier classification, reached 29.63%, indicating significant tumor regression, while 70.37% exhibited residual disease, either invasive or in situ. These findings highlight the effectiveness of the dose-dense 4AC-4T NAC regimen in downstaging tumors and improving surgical outcomes in stage III breast cancer patients.