title: Circulating tumor cells and prognosis of patients with resectable colorectal liver metastases or widespread metastatic colorectal cancer: a meta-analysis.
abstract: BACKGROUND
  We performed a systematic review and meta-analysis to investigate the prognostic value of tumor cells in blood (circulating tumor cells [CTCs]) or bone marrow (BM) (disseminated tumor cells) of patients with resectable colorectal liver metastases or widespread metastatic colorectal cancer (CRC).
  
  
  METHODS
  The following databases were searched in May 2011: MEDLINE, EMBASE, Science Citation Index, BIOSIS, Cochrane Library. Studies that investigated the association between tumor cells in blood or BM and long-term outcome in patients with metastatic CRC were included. We extracted hazard ratios (HRs) and confidence intervals (CIs) from the included studies and performed random-effects meta-analyses for survival outcomes.
  
  
  RESULTS
  The literature search yielded 16 studies representing 1,491 patients. The results of 12 studies representing 1,329 patients were suitable for pooled analysis. The overall survival (HR, 2.47; 95 % CI 1.74-3.51) and progression-free survival (PFS) (HR, 2.07; 95 % CI 1.44-2.98) were worse in patients with CTCs. The subgroup of studies with more than 35 % CTC-positive patients was the only subgroup with a statistically significant worse PFS. All eight studies that performed multivariable analysis identified the detection of CTCs as an independent prognostic factor for survival.
  
  
  CONCLUSIONS
  The detection of CTCs in peripheral blood of patients with resectable colorectal liver metastases or widespread metastatic CRC is associated with disease progression and poor survival.
authors: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. bas@grootkoerkamp.com
authors: Bas
authors: B
authors: Groot Koerkamp
authors: Nuh N
authors: NN
authors: Rahbari
authors: Markus W
authors: MW
authors: Büchler
authors: Moritz
authors: M
authors: Koch
authors: Jürgen
authors: J
authors: Weitz
mesh_terms: D015179:Colorectal Neoplasms / Q000473:pathology*; D016001:Confidence Intervals; D018572:Disease-Free Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000556:secondary*; D009360:Neoplastic Cells, Circulating; D011379:Prognosis