EP298/#540 Evaluation of external validity of the OVHIPEC-1 trial in a real-world population

ObjectivesThe OVHIPEC-1 trial showed improved overall survival (OS) and recurrence-free survival when interval cytoreductive surgery (CRS) was combined with hyperthermic intraperitoneal chemotherapy (HIPEC) in women with stage III epithelial ovarian cancer (EOC). We compared the trial population to a real-world population diagnosed and treated during the same period to explore the generalizability of the trial results.MethodsAll patients undergoing interval CRS between 2007–2016 were identified from the nationwide Netherlands Cancer Registry if they fulfilled the key eligibility criteria of OVHIPEC-1. We compared patient and treatment characteristics, and OS between the control arm of the trial and the real-world population.ResultsThe distribution of age, comorbidity, BRCA-status, histologic subtype, and completeness of CRS were similar in trial and non-trial patients. The trial population had a better performance status and a higher socioeconomic status compared to the real-world population. Trial patients underwent bowel surgery more often. The vast majority of patients received 6 cycles of chemotherapy. In real-world setting, patients received more often >6 cycles. The difference in OS between the trial and the real-world population was not statistically significant (figure 1).ConclusionsDespite differences in patient and treatment characteristics, OS of patients treated in the control arm of OVHIPEC-1 was similar to patients treated outside the trial. This finding does not lend support for the hypothesis that the survival benefit seen in the trial was caused by inferior outcome of patients selected for the trial. These results support the administration of HIPEC in stage III EOC patients undergoing interval CRS in clinical practice.