Objective The aim of this study was to investigate the prognostic significance of a pretreatment thrombocytosis and its association with neutrophilia in patients with surgically treated endometrial cancer.

Methods The baseline characteristics and outcome data of 508 patients with surgically treated endometrial cancer between January 2000 and December 2010 were collected and retrospectively reviewed. The patients were separated into 4 groups according to their platelet counts and the neutrophil counts, and the progression-free and overall survival rates of the 4 groups were compared. A Cox proportional hazards regression model was used to explore the independent prognostic factors.

Results Pretreatment thrombocytosis was found to be associated with advanced stage (P = 0.0186), nonendometrioid histology (P = 0.0139), a deeper myometrial invasion (P = 0.0103), lymphovascular space involvement (P = 0.0404), cervical involvement (P = 0.004), positive peritoneal cytology (P = 0.0198), lymph node metastasis (P = 0.0301), and more frequent treatment failure (P = 0.0006). Multivariate analysis demonstrated that an older age (hazard ratio [HR], 2.54; 95% confidence interval [CI], 1.46–4.51; P = 0.0009), advanced clinical stage (HR, 5.27; 95% CI, 2.94–9.86; P < 0.0001), lymphovascular space involvement (HR, 3.37; 95% CI, 1.74–7.07; P = 0.0002), and pretreatment thrombocytosis (HR, 4.99; 95% CI, 2.47–9.39; P < 0.0001) were significant predictors of survival. When examined according to clinical stage, pretreatment thrombocytosis was prognostically significant only in patients with stage III–IV disease. The neutrophil count in patients who display thrombocytosis was significantly greater than that observed in patients without thrombocytosis (median, 6702 vs 4406/μL; P < 0.0001). Moreover, patients who displayed both thrombocytosis and neutrophilia had significantly shorter survival than that in those with either thrombocytosis or neutrophilia alone.

Conclusions Presence of thrombocytosis at the time of the initial diagnosis is an independent predictor of shorter survival in patients with advanced-stage (stages III–IV) endometrial cancer. Moreover, pretreatment thrombocytosis and concurrent neutrophilia are an independent predictor of shorter survival regardless of clinical stage.