Circulating Tumor DNA as a Predictive Marker of Recurrence for Patients With Stage II-III Breast Cancer Treated With Neoadjuvant Therapy

Po-Han Lin; Ming-Yang Wang; Chiao Lo; Li-Wei Tsai; Tzu-Chun Yen; Thomas Yoyan Huang; Wei-Chih Huang; Karen Yang; Chih-Kai Chen; Sheng-Chih Fan; Sung-Hsin Kuo; Chiun-Sheng Huang

doi:10.3389/fonc.2021.736769

Circulating Tumor DNA as a Predictive Marker of Recurrence for Patients With Stage II-III Breast Cancer Treated With Neoadjuvant Therapy

Front Oncol. 2021 Nov 12:11:736769. doi: 10.3389/fonc.2021.736769. eCollection 2021.

Authors

Po-Han Lin^{1

2}, Ming-Yang Wang³, Chiao Lo³, Li-Wei Tsai³, Tzu-Chun Yen¹, Thomas Yoyan Huang¹, Wei-Chih Huang¹, Karen Yang⁴, Chih-Kai Chen¹, Sheng-Chih Fan¹, Sung-Hsin Kuo⁵, Chiun-Sheng Huang^{3

6}

Affiliations

¹ Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.
² Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan.
³ Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
⁴ Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
⁵ Department of Medical Oncology, National Taiwan University Hospital, Taipei, Taiwan.
⁶ Department of Surgery, College of Medicine, National Taiwan University, Taipei, Taiwan.

Abstract

Background: Patients with stage II to III breast cancer have a high recurrence rate. The early detection of recurrent breast cancer remains a major unmet need. Circulating tumor DNA (ctDNA) has been proven to be a marker of disease progression in metastatic breast cancer. We aimed to evaluate the prognostic value of ctDNA in the setting of neoadjuvant therapy (NAT).

Methods: Plasma was sampled at the initial diagnosis (defined as before NAT) and after breast surgery and neoadjuvant therapy(defined as after NAT). We extracted ctDNA from the plasma and performed deep sequencing of a target gene panel. ctDNA positivity was marked by the detection of alterations, such as mutations and copy number variations.

Results: A total of 95 patients were enrolled in this study; 60 patients exhibited ctDNA positivity before NAT, and 31 patients exhibited ctDNA positivity after NAT. A pathologic complete response (pCR) was observed in 13 patients, including one ER(+)Her2(-) patient, six Her2(+) patients and six triple-negative breast cancer (TNBC) patients. Among the entire cohort, multivariate analysis showed that N3 classification and ctDNA positivity after NAT were independent risk factors that predicted recurrence (N3, hazard ratio (HR) 3.34, 95% confidence interval (CI) 1.26 - 8.87, p = 0.016; ctDNA, HR 4.29, 95% CI 2.06 - 8.92, p < 0.0001). The presence of ctDNA before NAT did not affect the rate of recurrence-free survival. For patients with Her2(+) or TNBC, patients who did not achieve pCR were associated with a trend of higher recurrence (p = 0.105). Advanced nodal status and ctDNA positivity after NAT were significant risk factors for recurrence (N2 - 3, HR 3.753, 95% CI 1.146 - 12.297, p = 0.029; ctDNA, HR 3.123, 95% CI 1.139 - 8.564, p = 0.027). Two patients who achieved pCR had ctDNA positivity after NAT; one TNBC patient had hepatic metastases six months after surgery, and one Her2(+) breast cancer patient had brain metastasis 13 months after surgery.

Conclusions: This study suggested that the presence of ctDNA after NAT is a robust marker for predicting relapse in stage II to III breast cancer patients.

Keywords: breast cancer; circulating tumor DNA; neoadjuvant therapy; next-generation sequencing; recurrence.