External validation of three prognostic models for overall survival in patients with advanced-stage epithelial ovarian cancer

Background: For various malignancies, prognostic models have shown to be superior to traditional staging systems in predicting overall survival. The purpose of this study was to validate and compare the performance of three prognostic models for overall survival in patients with advanced-stage epithelial ovarian cancer. Methods: A multi-institutional epithelial ovarian cancer database was used to identify patients and to evaluate the predictive performance of two nomograms, a prognostic index and FIGO (International Federation of Obstetrics and Gynecology) stage. All patients were treated for advanced-stage epithelial ovarian cancer between January 1996 and January 2009 in 11 hospitals in the eastern part of The Netherlands. Results: In total, 542 patients were found to be eligible. Overall performance did not differ between the three prognostic models and FIGO stage. The discriminative performance for Chi's model was moderately good (c indices 0.65 and 0.68) and for the models of Gerestein and Teramukai reasonable (c indices between 0.60 and 0.62). The c indices of FIGO stage ranged between 0.54 and 0.62. After recalibration, the three models showed almost perfect calibration, whereas calibration of FIGO stage was reasonable. Conclusion: The three prediction models showed general applicability and a reasonably well-predictive performance, especially in comparison to FIGO stage. To date, there are no studies available that analyse the impact of these prognostic models on decision-making and patient outcome. Therefore, the usefulness of these models in daily clinical practice remains to be investigated.