Prognostic role of thrombocytosis in recurrent ovarian cancer: a pooled analysis of the AGO Study Group.

PURPOSE: Although thrombocytosis in patients with primary ovarian cancer has been widely investigated, there are only very few data about the role of thrombocytosis in recurrent ovarian cancer. The aim of our study was to investigate the impact of pretreatment thrombocytosis prior to chemotherapy on clinical outcome in patients with recurrent platinum eligible ovarian cancer.

METHODS: In our retrospective analysis we included 300 patients who were treated by AGO Study Group Centers within three prospective, randomized phase-III-trials. All patients included had been treatment-free for at least 6 months after platinum-based chemotherapy. We excluded patients who underwent secondary cytoreductive surgery before randomization to the trial. Thrombocytosis was defined as a platelet count of ≥ 400⋅109 /L.

RESULTS: Pretreatment thrombocytosis was present in 37 out of 300 (12.3%) patients. Patients with thrombocytosis responded statistically significantly less to chemotherapy (overall response rate 35.3% and 41.6%, P = 0.046). The median progression-free survival (PFS) for patients with thrombocytosis was 6.36 months compared to 9.00 months for patients without thrombocytosis (hazard ratio [HR] = 1.19, 95% confidence interval [CI] = 0.84-1.69, P = 0.336). Median overall survival (OS) of patients with thrombocytosis was 16.33 months compared to 23.92 months of patients with a normal platelet count (HR = 1.46, 95% CI = 1.00-2.14, P = 0.047).

CONCLUSIONS: The present analysis suggests that pretreatment thrombocytosis is associated with unfavorable outcome with regard to response to chemotherapy and overall survival in recurrent ovarian cancer.