Platelet count as a biomarker for monitoring treatment response and disease recurrence in recurrent epithelial ovarian cancer

OBJECTIVES: We sought to determine the impact of pretreatment plasma platelet levels, dimerized plasmin fragment (D-dimer) and fibrinogen in recurrent epithelial ovarian cancer (EOC) and the impact of platelet levels on SKOV3 cell lines growth and responsiveness to chemotherapy. METHODS: Under approval of ethical committee, we identified 104 women with recurrent EOC who underwent treatment between January 2010 and February 2015. Reviewing clinical, laboratory, and pathologic records from this retrospective cohort, we analyzed the correlation between pretreatment plasma D-dimer, fibrinogen, platelet levels and clinicopathological parameters, progression free survival (PFS) and overall survival (OS). Inco-culture experiments human ovarian cancer SKOV3 cell lines were used to test the effect of platelet levels on tumor growth and responsiveness to docetaxel. RESULTS: Of the 104 recurrent EOC, thrombocytosis at diagnosis and the decrease of platelet count by less than 25% after primary therapy were associated with worse median progression free survival (P = 0.003;P = 0.021) and median overall survival (P = 0.009;P = 0.009). Mean platelet levels declined at the end of primary therapy(P < 0.001) and rose at recurrence(P = 0.007). In multivariate analysis, elevated platelet levels at primary therapy and the decrease of platelet count less than 25% after primary therapy were unfavorable prognostic factor for PFS(P = 0.022; P = 0.015) and OS(P = 0.013;P = 0.007) in recurrent EOC, but elevated plasma D-dimer and fibrinogen were not. In SKOV-3 ovarian cancer cell lines, suitable concentration platelet co-culture protected against apoptosis (P < 0.05). CONCLUSIONS: Platelet count during treatment could be used as a biomarker used for monitoring the disease recurrence and predicting treatment response. And platelet with suitable concentration co-culture protected against apoptosis in SKOV3 cell line, which may explain clinical observations.