title: Prognostic value of circulating tumor cells in metastatic breast cancer: a systemic review and meta-analysis.
abstract: OBJECTIVE
  Metastatic breast cancer (MBC) remains the main cause of cancer-related death, and the clinical significance and prognostic role of circulating tumor cells (CTCs) in metastatic breast cancer are still controversial. Here, we conducted a meta-analysis to clarify the correlation between CTCs and the clinicopathological features and prognosis of MBC.
  
  
  METHODS
  We performed a comprehensive search of Pubmed and the ISI Web of Science through December 2014. Only articles that focused on MBC patients and detected CTCs using the CellSearch system were included. The associations between CTCs and survival rate and clinicopathological parameters, including molecular pattern, metastatic region and treatment response, were evaluated.
  
  
  RESULTS
  This meta-analysis included 24 studies (3701 MBC patients), 13 prospective studies and 11 retrospective studies. We found that CTCs were more frequently detected with HER2 + primary tumors (pooled RR = 0.73, 95 % CI = 0.63-0.84). Additionally, higher CTC numbers indicated a worse treatment response (RR = 0.56, 95 % CI = 0.40-0.79), poorer PFS (RR = 0.64, 95 % CI = 0.56-0.73) and poorer OS (RR = 0.69, 95 % CI = 0.64-0.75) in MBC patients.
  
  
  CONCLUSIONS
  Based on these results, we propose that HER2 positivity could be a significant risk factor for the presence of CTCs. Additionally, CTCs have a significant prognostic value for MBC patients. Therefore, CTCs should be continually monitored to guide the treatment of MBC patients, especially those with HER2 + primary tumors.
authors.affiliation: Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, National Ministry of Education, Provincial Key Laboratory of Molecular Biology in Medical Sciences), The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Lv
authors.affiliation: Department of Otorhinolaryngology, Affiliated Cixi Hospital of Wenzhou Medical College, Cixi, 315300, China.
authors.forename: L
authors.initials: L
authors.lastname: Gong
authors.affiliation: Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, National Ministry of Education, Provincial Key Laboratory of Molecular Biology in Medical Sciences), The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, National Ministry of Education, Provincial Key Laboratory of Molecular Biology in Medical Sciences), The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
authors.forename: J
authors.initials: J
authors.lastname: Ye
authors.affiliation: Department of Otorhinolaryngology, First Affiliated Hospital, Medical School, Zhejiang University, Hangzhou, 310003, China.
authors.forename: L
authors.initials: L
authors.lastname: Chai
authors.affiliation: Department of Breast Surgery, Zhejiang Provincial People's Hospital, Hangzhou, 310004, China.
authors.forename: C
authors.initials: C
authors.lastname: Ni
authors.affiliation: Department of Otorhinolaryngology, First Affiliated Hospital, Medical School, Zhejiang University, Hangzhou, 310003, China. davenc@163.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Mao
mesh_terms: D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: Breast cancer; Circulating tumor cells; Her2; Meta-analysis; Prognosis