Usefulness of the preoperative platelet count in the diagnosis of adnexal tumors

Platelets seem to play a role in the development of ovarian cancer. Platelet count (PLT) is an ubiquitous available parameter. We analyzed retrospectively data of 756 patients with primary adnexal tumors: 584 benign and 172 malignant (148 invasive and 24 borderline) cases. We compared the diagnostic accuracy of CA125, PLT, and a combination of CA125 and PLT. The cutoff values for CA125 and PLT were 35 U/ml and 350/nl, respectively. The median age of patients with benign and malignant tumors was 45 and 64 years, respectively. A total of 77/172 (44.8 %) malignant and 50/584 (8.6 %) benign cases presented with thrombocytosis (PLT ≥350/nl). The median PLT differed between benign and malignant cases (257/nl vs. 330/nl; p < 0.001), similarly as CA125 did (17 vs. 371 U/ml; p < 0.001). In the multivariate analysis, age, CA125, and thrombocytosis predicted independently the presence of malignancy. The results of CA125 were false positive in 21 % and false negative in 13 %. If considered together, thrombocytosis + CA125 were false positive only in 9 %, whereas the false negative rate was 12 %. The sensitivity and specificity of CA125, thrombocytosis, and thrombocytosis + CA125 for detecting adnexal malignancy were 0.88/0.78, 0.45/0.91, and 0.81/0.94, respectively. The positive predictive value (PPV) of CA125, thrombocytosis, and thrombocytosis + CA125 was 0.79, 0.61, and 0.91, respectively. In conclusion, PLT is an ubiquitously available parameter that could be useful in the diagnostic evaluation of pelvic mass. Considering thrombocytosis additionally to CA125 improves the specificity and PPV and reduces the false positive rate in detecting adnexal malignancy.