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

To construct a nomogram of individual risks from exploratory clinicopathological features associated with platinum-resistant/refractory epithelial ovarian cancer (EOC).

Patients 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.

Of 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.

One-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.