The prognostic value of chemotherapy or endocrine therapy choice according to circulating tumor cell count in HR+HER2- metastatic breast cancer: a retrospective study.

Abstract

BackgroundCirculating tumor cell (CTC) count have prognostic role for metastatic breast cancer (MBC). No clear biomarkers can guide selection of chemotherapy (CT) or endocrine therapy (ET) in 1st-line setting of hormone-receptor positive and human epidermal growth factor receptor 2 negative (HR+HER2−) MBC. The present study investigated the prognostic role CT or ET according to the CTC count in HR+HER2− MBC.MethodsWe consecutively collected the data of 53 HR+HER2− MBC patients who received 1st-line CT or ET, who had CTC count detected by our peptide-based nanomagnetic CTC isolation system (Pep@MNPs) from January 2014 to December 2015. The clinicopathological characteristics according the CTC count and 1st-line ET vs. CT were compared. Follow-up was conducted every 6 months. The primary endpoint was progression-free survival (PFS) and overall survival (OS). A Cox regression analysis was conducted to determine the prognostic roles of CTC and 1st-line therapy of ET vs. CT for PFS and OS.ResultsThe median CTC count of the 53 patients was 2 (range, 0–18). The clinicopathological characteristics of the patients in the CTC count <2 group and the CTC count ≥2 group were similar. The patients with a CTC count <2 had a significantly longer PFS than those with a CTC count ≥2 (P=0.005, hazard ratio =4.138, 12.1 vs. 7.1 months). The patients who received CT had a significantly longer PFS than those who received ET (P=0.041, hazard ratio =2.721, 9.9 vs. 7.2 months). In the CTC count ≥2 group, the patients who received CT had a significantly longer PFS than those who received ET (P=0.048, hazard ratio =2.475, 8.7 vs. 6.3 months). In the CTC count <2 group, there was no significant difference in PFS between the CT and ET groups (P=0.071). Additionally, the CTC count had no significant effect on OS (P=0.116, hazard ratio =2.391, 54.2 vs. 34.2 months).ConclusionsThe present study showed that CTC count determined by the Pep@MNP system confirmed the prognostic value in the HR+HER2− MBC patients. And it might be helpful in choosing a 1st-line treatment of CT or ET for HR+HER2− MBC patients.