To investigate the value of circulating tumor cells (CTC) in evaluating the efficacy of chemotherapy in patients with advanced breast cancer.

Fifty patients with advanced breast cancer diagnosed in the Breast Center of Liaocheng People’s Hospital from July 2016 to June 2018 were selected. Negative enrichment, immunocytochemistry CD45 staining and ?uorescence in situ hybridization (FISH) was used to identify, enumerate and characterize CTC during chemotherapy of advanced breast cancer patients, and the data of imaging and serological indexes were collected to compare the changes of CTC number during chemotherapy of patients and to compare with imaging and serological indexes.

For the first time, there were 18 cases (36.0%) with CTC count 5, 28 cases (56.0%) with CTC count 1, and 4 cases (8.0%) with no CTC. The number of CTC was decreased in 32 cases and increased in 18 cases. The changes of CTC and imaging indicators were basically the same, and there was no significant difference between the changes of CTC count and imaging indicators in evaluating disease changes (kappa=0.65, χ²=0.125, P=0.724). The changes of serological indicators in the development of advanced breast cancer were statistically significant compared with those of imaging CEA (kappa=0.19, χ²=4.267, P=0.039), CK19 (kappa=0.16, χ²=6.667, P=0.010), CA15-3 (kappa=0.01, χ²=4.500, P=0.034).

CTC counts have certain clinical value in predicting the disease progression of patients with advanced breast cancer, and changes in CTC counts are more sensitive than serological indicators in predicting the risk of disease progression for patients with advanced breast cancer.