A RISK MODEL FOR SECONDARY CYTOREDUCTIVE SURGERY IN RECURRENT OVARIAN CANCER: AN EVIDENCE-BASED PROPOSAL FOR PATIENT SELECTION

Background: To develop a risk model for predicting complete secondary cytoreductive surgery (SCR) in patients with recurrent ovarian cancer. Methods: Individual data of 1075 patients with recurrent ovarian cancer undergoing SCR from seven world-wide centers were pooled and analyzed. The risk model was developed based on the factors impacting on SCR surgical outcome. Additional data on 117 patients who were not included in the development of the model were used for external validation and to assess the discrimination of the model. Results: Of the 1075 patients, 434 (40.4%) underwent complete resection. Complete secondary cytoreduction was associated with six variables: FIGO stage (OR=1.32, 95%CI: 0.97-1.80), residual disease after primary cytoreduction (OR=1.69, 95%CI: 1.26-2.27), progression-free interval (OR=2.27, 95%CI: 1.71-3.01), ECOG performance status (OR=2.23, 95%CI: 1.45-3.44), CA125 (OR=1.85, 95%CI: 1.41-2.44) and ascites at recurrence(OR=2.79, 95%CI: 1.88-4.13). These variables were entered into the risk model and assigned scores ranging from 0 to 11.9. Patients with total scores of 0-4.7 were categorized as the low risk group, in which the proportion of complete cytoreduction was 53.4% compared to 20.1% in the high risk group (OR=4.55, 95%CI: 3.43-6.04). In external validation, the sensitivity and specificity was 83.3% and 57.6%, respectively. Area under the curve of the receiveroperating characteristics for predicting complete SCR was 0.68 (95%CI: 0.60-0.79). Conclusions: This model and scoring system may well predict the outcome of SCR and could potentially be useful in future clinical trials to determine which patients with recurrent ovarian cancer should have SCR as part of their management.