RT Journal Article SR Electronic T1 Thrombocytosis Portends Adverse Prognosis in Colorectal Cancer: A Meta-Analysis of 5,619 Patients in 16 Individual Studies JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 4717 OP 4726 VO 37 IS 9 A1 DONGMIN GU A1 ARPAD SZALLASI YR 2017 UL http://ar.iiarjournals.org/content/37/9/4717.abstract AB Aim: The current study aimed to determine the prognostic significance of thrombocytosis in patients with colorectal cancer (CRC) by a meta-analysis of the literature. Patients and Methods: The meta-analysis followed the 2009 guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A systematic literature review was conducted from PubMed and Web of Science for articles published up to May 15, 2015. Sixteen studies with a total of 5,619 patients met the inclusion criteria. Hazard ratios and 95% confidence intervals were retrieved from the original articles, calculated from the published Kaplan–Meier survival curves, or the corresponding authors were contacted for additional information. Heterogeneity was assessed using the I2 statistic and Chi-square tests. Publication bias was assessed by Begg's funnel plot, Egger's linear regression test and trim-and-fill method. Sensitivity analysis was performed to validate the reliability. Results: Thrombocytosis is associated with shorter overall, disease-free and cancer-specific survival. Overall survival is reduced in patients with thrombocytosis regardless of their clinical tumor stage, and ethnicity. Shortened disease-free survival is associated with elevated platelet count in the non-specific stage (I-IV), localized tumor (stage I-III), and in the Asian patient population. Thrombocytosis is further associated with reduced cancer-specific survival in the non-specific stage and in Asian patients. Finally, thrombocytosis is significantly related to female patients, colon tumor location, T3-4 stage, lymph node positivity, metastasis, undifferentiated histology and lymphatic involvement. Conclusion: Thrombocytosis portends adverse prognosis in CRC, and may serve as a clinically useful marker to facilitate risk stratification and guide postoperative management.