Ovarian cancer is a lethal gynecological malignancy. Although CA-125 is commonly measured in women with adnexal mass, it is estimated that it only has a positive predictive value (PPV) of 69% and a negative predictive value (NPV) of 88% for the detection of ovarian cancer. The aim of this study was to investigate the diagnostic significance and predictive impact of thrombocytosis in women with suspected or confirmed ovarian cancer. This was a retrospective study of women who had surgery for adnexal mass over a 48-month period between September 2014 and September 2018 at Swansea Gynecological Oncology Center in Wales, UK. A total of 294 women who underwent surgery for high-risk pelvic mass or biopsy-confirmed ovarian cancer were identified. 206 women (70%) had final histology confirming ovarian cancer, 54 women (18%) had benign tumors while 34 women (12%) had borderline tumors. 90/206 women (43.7%) with ovarian cancer had thrombocytosis prior to primary surgery or neoadjuvant chemotherapy compared to 8/54 (14.8%) for benign tumors and 4/34 (11.8%) for borderline tumors. Thrombocytosis was observed in 23.2%, 40%, 45.1%, and 65.1% of Stages I, II, III, and IV ovarian cancer, respectively. Thrombocytosis was a stronger predictor of ovarian malignancy in younger women of less than 60 years (p = .041). Overall, the positive likelihood ratio of platelet count in the detection of ovarian cancer was 2.61 while the negative likelihood ratio was 0.72, with a diagnostic odds ratio of 3.625. Thrombocytosis was strongly associated with advanced stage ovarian cancer (Stage III/IV) (p = .002). Interestingly, 4/8 (50%) women with thrombocytosis in the benign ovarian tumor group were diagnosed with ovarian fibroma/fibrothecoma, which often mimics advanced ovarian cancer at presentation. Predictive markers for borderline tumors continue to remain a challenge. We believe that there is a role for platelet count in primary care algorithm for women with suspected ovarian cancer. We suspect that platelets play a role in the metastasis of ovarian cancer.
Keywords: Ascites; Thrombocytosis; fibroma; fibrothecoma; ovarian cancer; pelvic mass; platelets.