Preoperative thrombocytosis predicts prognosis in stage II colorectal cancer patients

PURPOSE Thrombocytosis is known to be a poor prognostic factor in several types of solid tumors. The prognostic role of preoperative thrombocytosis in colorectal cancer remains limited. The aim of this study is to investigate the prognostic role of preoperative thrombocytosis in stage II colorectal cancer. METHODS Two hundred eighty-four patients with stage II colorectal cancer who underwent surgical resection between December 2003 and December 2009 were retrospectively reviewed. Thrombocytosis was defined as platelet > 450 × 10(9)/L. We compared patients with thrombocytosis and those without thrombocytosis in terms of survival. RESULTS The 5-year disease-free survival (DFS) rates were lower in patients with thrombocytosis compared to those without thrombocytosis in stage II colorectal cancer (73.3% vs. 89.6%, P = 0.021). Cox multivariate analysis demonstrated that thrombocytosis (hazard ratio, 2.945; 95% confidence interval, 1.127-7.697; P = 0.028) was independently associated with DFS in patients with stage II colorectal cancer. CONCLUSION This study showed that thrombocytosis is a prognostic factor predicting DFS in stage II colorectal cancer patients.