Circulating tumor cells in breast cancer and its association with tumor clinicopathological characteristics: a meta-analysis

The aim of the study was to evaluate the association between tumor clinicopathological characteristics and circulating tumor cells (CTCs) in breast cancer. We searched PubMed, MEDLINE, BioMed, and EMbase databases for studies that assessed the association between tumor clinicopathological characteristics and CTCs in breast cancer. Studies obtained from search strategy were screened using pre-specified criteria, and necessary data were retrieved for meta-analysis. Fourteen studies with 2,336 patients were eligible for combined analysis. Presence of CTCs in peripheral blood (PB) was significantly associated with tumor size [OR 0.68, 95 % confidence interval (CI) (0.54, 0.87), n = 10, P = 0.002], tumor grade [OR 0.71, 95 % CI (0.55, 0.91), n = 8, P = 0.006], ER status [OR 0.72, 95 % CI (0.57, 0.91), n = 9, P = 0.007], and PR status [OR 0.78, 95 % CI (0.61, 0.98), n = 9, P = 0.04]. However, as to correlation between nodal status and CTCs presence in PB, no statistically significant difference was found [OR 0.83, 95 % CI (0.67, 1.03), n = 12, P = 0.10]. The CTCs’ presence in PB is correlated with tumor size, tumor grade, ER, and PR.