Introduction: Thrombocytosis is present in a wide range of malignancies, with a reported incidence of 10% to 57%. Several reports have documented thrombocytosis at the time of diagnosis as a poor prognostic indicator. Our study is the first report evaluating the role of preoperative thrombocytosis and its association with survival in a predominantly African American and Caribbean American urban population.

Materials and Methods: We retrospectively reviewed the charts of 99 consecutive patients treated for endometrial carcinoma at SUNY Downstate Medical Center. Seventy-seven patients were deemed eligible for the study, and the following clinicopathologic characteristics were recorded from their medical records: age, stage, grade, histological subtype, presence of lymphovascular space invasion, depth of myometrial invasion, intrauterine tumor volume, preoperative prothrombin time, activated partial thromboplastin time, platelet count, progression-free survival (PFS), and overall survival (OS). The data were analyzed using Spearman and Pearson correlations, Student t test, χ² test, and Fisher exact test. Survival analysis was performed using Kaplan-Meier tables, log-rank test, and Cox proportional hazard model. The 2-tailed value of P < 0.05 was considered significant.

Results: Fourteen (18.2%) of 77 patients exhibited thrombocytosis (platelet count, >400 × 10⁹/L). Patients with advanced disease (stages III-IV) had a significantly higher mean preoperative platelet count (359 ± 23.8 × 10⁹/L) in comparison with patients with localized disease (stages I-II, 283 ± 14.3 × 10⁹/L, P = 0.005). The median PFS among patients with stages III and IV without preoperative thrombocytosis was 15.0 ± 4.8 months (n = 21) and with thrombocytosis was 3.0 ± 1.4 months (n = 8, P = 0.032). The median OS in patients without thrombocytosis was 24.0 ± 4.5 months (n = 21) and in patients with thrombocytosis was 7.0 ± 3.8 months (n = 8, P = 0.015). Multivariate analysis was performed using log-rank test and Cox proportional hazard model. The only variables that retained independent prognostic significance were stage (hazards ratio, 3.268; P = 0.040) and preoperative thrombocytosis (hazards ratio, 1.714 per 100 platelets; P = 0.030). Among patients with localized disease, preoperative thrombocytosis was not associated with worsened OS or PFS.

Conclusions: Our data indicate that preoperative thrombocytosis among high-risk inner-city patients with stages III to IV endometrial cancer is an independent prognostic indicator. This is the first such report in a predominantly African American and Caribbean American population. Further research is needed to elucidate the mechanisms of thrombocytosis in malignancy. Association of thrombocytosis and aggressive tumor behavior warrants investigation of antiplatelet therapy and its effect on outcome.