Detection of circulating tumor cells predicts the efficacy of neoadjuvant chemotherapy for locally advanced triple-negative breast cancer

Cong Wang Jingyue Li Tingli Luo Shenglin Zhu Mingda Zhao Yicai Jia Yefu Liu ^*

• Department of Breast Surgery, Liaoning Cancer Hospital & Institute, Dalian Medical University, Dalian, China

Objective: This study aimed to assess the predictive potential of circulating tumor cells (CTCs) and circulating tumor stem cells (CTSCs) in locally advanced triple-negative breast cancer (TNBC) undergoing neoadjuvant chemotherapy (NAC) compared to the RECIST 1.1 standard.We analyzed 112 TNBC patients at Liaoning Tumor Hospital. CTCs and CTSCs were evaluated before NAC, on the first NAC cycle day, and after it. We assessed the ability of positive CTSCs post-first cycle to predict NAC resistance (requiring regimen change) with 91% specificity.Additionally, we analyzed CTC dynamics during the first NAC cycle to predict efficacy (often reaching MP4 or MP5) with 87% sensitivity and 80% specificity.Results: Positive CTSCs post-first cycle predicted NAC resistance with high specificity (91%). CTCs' gradual decline during the first NAC cycle indicated NAC efficacy, allowing the regimen to continue with sensitivity of 87% and specificity of 80%.This study suggests that positive CTSCs post-first NAC cycle predict resistance, offering early detection (≥ 6 weeks earlier than RECIST). Gradual CTC reduction during the first cycle predicts efficacy, enabling regimen continuation. CTCs and CTSCs show promise as predictive markers for NAC efficacy in locally advanced TNBC patients.