Detection of Circulating Tumor Cells in the Prognostic Significance of Patients With Breast Cancer: A Retrospective Study.

Background: Breast cancer (BC) is an aggressive tumor. Circulating tumor cells (CTCs) are a potential biomarker for the prognosis of cancer patients. This study aimed to explore the prognostic significance of CTCs in patients with BC.

Methods: Retrospectively, 108 BC patients were collected between January 2011 and December 2019, while 10 patients with benign nodules were included as controls. CTCs with different phenotypes of patients were isolated using CanPatrol and tricolor RNA in situ hybridization (RNA-ISH) methods. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) levels were measured by immunohistochemistry (IHC). The progression-free survival (PFS) was calculated using the Kaplan-Meier method. Independent risk factors for BC recurrence were determined by Cox proportional risk regression analysis.

Results: The higher the cancer stage (p = 0.00), the higher the ki-67 expression level (p < 0.01), and the lower the histologic grade (p < 0.01), the higher the number of CTCs. The PFS of patients with high CTCs was shorter than that of patients with low CTCs (p < 0.05). Total CTCs (≥ 6) and positive mesenchymal CTCs (MCTCs) were also associated with recurrence and metastasis.

Conclusions: Total CTCs in BC patients have an independent influence on PFS reduction. Higher total CTCs and MCTCs in peripheral blood are biomarkers for predicting the prognosis of BC patients. HER-2 high expression is also associated with the prognosis of the disease.