Objective: Neoadjuvant chemotherapy (NAC) is currently used in both early stage and locally advanced breast cancers. The survival benefits of standard vs. non-standard NAC cycles are still unclear. This study aimed to investigate the relationship between NAC cycles and survival based on real world data. Methods: We identified patients diagnosed with invasive primary breast cancers who underwent NAC followed by surgery. Patients who received at least 4 NAC cycles were defined as having received standard cycles, while patients who received less than 4 NAC cycles were defined as having received non-standard cycles. Kaplan-Meier curves and Cox proportional hazard models were used to estimate the disease-free survival (DFS) and overall survival (OS). Results: Of the 1,024 included patients, 700 patients received standard NAC cycles and 324 patients received non-standard NAC cycles. The DFS estimates were 87.1％ and 81.0％ (P = 0.007) and the OS estimates were 90.0％ and 82.6％ (P = 0.001) in the standard and non-standard groups, respectively. Using multivariate analyses, patients treated with standard NAC cycles showed significant survival benefits in both DFS [hazard ratio (HR): 0.62, 95％ confidence interval (CI): 0.44–0.88] and OS (HR: 0.54, 95％ CI: 0.37–0.79). Using stratified analyses, standard NAC cycles were associated with improved DFS (HR: 0.59, 95％ CI: 0.36–0.96) and OS (HR: 0.49, 95％ CI: 0.28–0.86) in the HER2 positive group. Similar DFS (HR: 0.50, 95％ CI: 0.25–0.98) and OS (HR: 0.45, 95％ CI: 0.22–0.91) benefits were shown for the triple negative group. Conclusions: Standard NAC cycles were associated with a significant survival benefit, especially in patients with HER2 positive or triple negative breast cancer.

Litong Yao;Zhiyuan Pang;Mozhi Wang;Mengshen Wang;Xiangyu Sun;Mingke Cui;Yanfu Zheng;Xinyan Li;Haoran Dong;Qiang Zhang;Yingying Xu

Department of Breast Surgery,the First Affiliated Hospital of China Medical University,Shenyang 110001,China;Department of Breast Surgery,Cancer Hospital of China Medical University,Liaoning Cancer Hospital&Institute,Shenyang 110042,China

癌症生物学与医学（英文版）

[1]Litong Yao;Zhiyuan Pang;Mozhi Wang;Mengshen Wang;Xiangyu Sun;Mingke Cui;Yanfu Zheng;Xinyan Li;Haoran Dong;Qiang Zhang;Yingying Xu-.The choice of a neoadjuvant chemotherapy cycle for breast cancer has significance in clinical practice: results from a population-based, real world study)[J].癌症生物学与医学（英文版）,2022(05):755-767

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