Abstract: OBJECTIVE: To evaluate the relationship between purple-bluish tongue and platelet counts, and further to examine their associations with the recurrence of epithelial ovarian cancer.METHODS: A total of 82 epithelial ovarian cancer patients were enrolled in this study. Cluster analysis was used for grouping patients' P_(RGB)(Red-R;Green-G; Blue-B; Average percentage of RGB, P_(RGB))values. Receiver operating characteristic(ROC)curve was performed for detecting the diagnostic standard of purple-bluish tongue. χ~2 test was used to assess the relationship between purple-bluishtongue and platelet counts, and the recurrence of epithelial ovarian cancer. The perioperative(preoperative) platelet level was examinedwith tongue image and disease recurrence.RESULTS: Tongue images were classified into two groups basing on P_(RGB) values of images by cluster analysis. The numbers of cases in cluster "1"(normal color tongue) was 16 and cluster "2"(purple-bluish tongue) was 66. Two groups of P_(RGB) values, classified by cluster analysis, were significantly correlated with vision-based tongue color recognition(Kappa = 0.852, P < 0.001). ROC curve showed that the ratio of P_B to PRhad the highest diagnostic value. The sensitivity and the specificity of the ratio of P_B to P_R were 95.3% and 88.9% respectively and the optimal cut-off point was 0.71. Purple-bluish tongue was significantly correlated with increased platelet counts(P < 0.001). Both the increased platelet counts(P = 0.01) and purple-bluish tongue were associated with recurrence of epithelial ovarian cancer(P < 0.001).CONCLUSION: The ratio of P_B to P_R greater than 0.71 could serve as an indicator for purple-bluish tongue diagnosing used in symptom pattern identification in Traditional Chinese Medicine. Purple-bluish tongue, associated with increased platelet counts, was also closely correlated with the recurrence of epithelial ovarian cancer.

Key words: Ovarian epithelial cancer, Tongue inspection, Cluster analysis, Recurrence, Platelet count