Evaluation of external validity of the OVHIPEC-1 trial in a real-world population.

Objective: The OVHIPEC-1 trial (Phase III randomised clinical trial for stage III ovarian carcinoma randomising between interval cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy) showed improved survival when interval cytoreductive surgery (CRS) was combined with hyperthermic intraperitoneal chemotherapy in patients with stage III epithelial ovarian cancer (EOC). The authors compared the control arm of the trial with a real-world population treated in the Netherlands during the same period to explore generalizability of the trial results.

Methods: For this nationwide comparative cohort study, all patients with EOC undergoing interval CRS between 2007 and 2016 were identified from the Netherlands Cancer Registry if they fulfilled the eligibility criteria of OVHIPEC-1 (n = 1376). Patient and treatment characteristics, and overall survival (OS) were compared between trial and real-world populations.

Results: Age, comorbidity, BRCA status, histologic subtype, and residual disease were similar in trial and real-world patients. Trial patients had a better performance status, higher socioeconomic status, and underwent bowel surgery more often. In a real-world setting, patients more often received more than six cycles. The difference in OS between the trial and the real-world populations was not statistically significant (unadjusted hazard ratio, 1.09 [95% confidence interval, 0.87-1.37]; P = 0.44).

Conclusion: Despite differences in patient characteristics, OS of patients treated in the control arm of OVHIPEC-1 was similar to patients treated outside the trial. The trial population accurately represents real-world patients with stage III EOC undergoing interval CRS in terms of outcome.