BACKGROUND Previous studies have reported that pretreatment thrombocytosis is associated with poor outcomes in several cancer types. This study was designed to evaluate the prognostic significance of preoperative thrombocytosis in patients with non-small cell lung cancer (NSCLC) who undergo surgery.

METHODS We retrospectively reviewed the records of 199 patients who underwent R0 resection for NSCLC between May 2003 and July 2006 at Seoul National University Bundang Hospital, Seongnam, Korea.

RESULTS The frequency of preoperative thrombocytosis was 7.5% (15/199). Patients with preoperative thrombocytosis had shorter overall survival (OS, P = 0.003) and disease-free survival (DFS, P = 0.005) than those without thrombocytosis. In multivariable analysis, patients with preoperative thrombocytosis had a significantly greater risk of death and recurrence than those without preoperative thrombocytosis (risk of death: hazard ratio (HR) 2.98, 95% confidence interval (CI) 1.39 to 6.37, P = 0.005; risk of recurrence: HR 2.47, 95% CI 1.22 to 5.01, P = 0.012). A tendency towards a shorter OS and DFS was observed in three patients with persistent thrombocytosis during the follow-up period when compared with those of patients who recovered from thrombocytosis after surgery.

CONCLUSIONS Preoperative thrombocytosis was valuable for predicting the prognosis of patients with NSCLC. Special attention should be paid to patients with preoperative and postoperative thrombocytosis.