Clinicopathological Nomogram for Predicting Platinum-Resistant/Refractory Epithelial Ovarian Cancer

ObjectiveTo construct a nomogram of individual risks from exploratory clinicopathological features associated with platinum-resistant/refractory epithelial ovarian cancer (EOC).MethodsPatients who were diagnosed with EOC stage IA-IB, grades 2-3, and greater than stage IC, from January 1, 2005, to December 30, 2013, after the debulking of the tumors, were studied retrospectively. Additionally, they had received adjuvant treatment with a paclitaxel-carboplatin regimen at Songklanagarind Hospital. The patients' data (demographic, surgical, laboratory, pathological results, and clinical outcomes) were collected. The clinicopathological features associated with platinum-refractory/resistant EOC were assessed using univariate and multivariate logistic regression analyses. Significant factors were used to construct a nomogram; the nomogram predictive accuracy was measured via a concordance index (c-index) and validated using the bootstrap validation method.ResultsOf 235 patients included, the prevalence of platinum-resistant/refractory EOC was 19.1% overall and 36.8% for recurrent EOC. The clinicopathological features associated with platinumrefractory/ resistant EOC were parity, size of residual tumor, grade, International Federation of Gynecology and Obstetrics (FIGO) staging, platelet count, and number of cycles of chemotherapy. The nomogram c-index and mean absolute error were 0.83 and 0.03, respectively.ConclusionOne-fifth of the women with EOC and one-third with recurrent EOC had platinum-refractory/resistant EOC. The clinicopathological features, including parity, size of residual tumor, grade, FIGO staging, platelet count, and number of cycles of chemotherapy, are useful as predictors of platinumrefractory/ resistant EOC. Patients with these significant factors and with a high probability of developing platinum-resistant/refractory EOC should be considered for close surveillance and be made aware of recurrent disease.