title: The prognostic value of circulating tumor cells in patients with melanoma: a systematic review and meta-analysis.
abstract: BACKGROUND
  The detection of circulating tumor cells (CTC) in patients with melanoma represents an appealing prognostic tool, but no consensus exists on this topic. We aimed to comprehensively and quantitatively summarize the evidence for the use of CTC to predict patients' clinical outcome.
  
  
  METHODS
  Fifty-three studies enrolling 5,433 patients were reviewed. Correlation of CTC status with tumor-node-metastasis disease stage and patients' overall (OS) and progression-free (PFS) survival was assessed by means of association statistics and meta-analysis, respectively.
  
  
  RESULTS
  CTC status correlated with both tumor-node-metastasis stage (stage I, 32%; stage II, 41.7%; stage III, 41.1%; stage IV, 47.4%; P(trend) < 0.0001) and survival (OS: hazard ratio, 2.42; 95% confidence interval, 1.7-3.45, P < 0.0001; PFS: hazard ratio, 2.45; 95% confidence interval, 1.78-3.38; P < 0.0001). However, statistical heterogeneity was significant for both OS and PFS, likely underscoring the wide variability in study design. Furthermore, CTC positivity rates in early stages were higher and in the metastatic setting were lower than expected, which indicates an unsatisfactory accuracy of currently available CTC detection assays.
  
  
  CONCLUSIONS
  Our findings suggest that CTC might have a clinically valuable prognostic power in patients with melanoma. However, the heterogeneity of the studies thus far published warrants caution not to overestimate the favorable results of pooled data.
authors.affiliation: Department of Oncological and Surgical Sciences, Surgery Branch, University of Padova, Padua, Italy. mocellins@hotmail.com
authors.forename: Simone
authors.initials: S
authors.lastname: Mocellin
authors.forename: Dave
authors.initials: D
authors.lastname: Hoon
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ambrosi
authors.forename: Donato
authors.initials: D
authors.lastname: Nitti
authors.forename: Carlo Riccardo
authors.initials: CR
authors.lastname: Rossi
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018572:Disease-Free Survival; D008207:Lymphatic Metastasis; D008545:Melanoma / Q000097:blood / Q000473:pathology; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis