Central radiology assessment of the randomized phase III open-label OVHIPEC-1 trial in ovarian cancer.

INTRODUCTION: Hyperthermic intraperitoneal chemotherapy (HIPEC) improved investigator-assessed recurrence-free survival and overall survival in patients with stage III ovarian cancer in the phase III OVHIPEC-1 trial. We analyzed whether an open-label design affected the results of the trial by central blinded assessment of recurrence-free survival, and tested whether HIPEC specifically targets the peritoneal surface by analyzing the site of disease recurrence. METHODS: OVHIPEC-1 was an open-label, multicenter, phase III trial that randomized 245 patients after three cycles of neoadjuvant chemotherapy to interval cytoreduction with or without HIPEC using cisplatin (100 mg/m2). Patients received three additional cycles of chemotherapy after surgery. Computed tomography (CT) scans and serum cancer antigen 125 (CA125) measurements were performed during chemotherapy, and during follow-up. Two expert radiologists reviewed all available CT scans. They were blinded for treatment allocation and clinical outcome. Central revision included Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 measurements and peritoneal cancer index scorings at baseline, during treatment, and during follow-up. Time to centrally-revised recurrence was compared between study arms using Cox proportional hazard models. Subdistribution models compared time to peritoneal recurrence between arms, accounting for competing risks. RESULTS: CT scans for central revision were available for 231 patients (94%) during neoadjuvant treatment and 212 patients (87%) during follow-up. Centrally-assessed median recurrence-free survival was 9.9 months in the surgery group and 13.2 months in the surgery+HIPEC group (HR for disease recurrence or death 0.72, 95% CI 0.55 to 0.94; p=0.015). The improved recurrence-free survival and overall survival associated with HIPEC were irrespective of response to neoadjuvant chemotherapy and baseline peritoneal cancer index. Cumulative incidence of peritoneal recurrence was lower after surgery+HIPEC, but there was no difference in extraperitoneal recurrences. CONCLUSION: Centrally-assessed recurrence-free survival analysis confirms the benefit of adding HIPEC to interval cytoreductive surgery in patients with stage III ovarian cancer, with fewer peritoneal recurrences. These results rule out radiological bias caused by the open-label nature of the study.

Cost Effectiveness of Interval Cytoreductive Surgery With Hyperthermic Intraperitoneal Chemotherapy in Stage III Ovarian Cancer on the Basis of a Randomized Phase III Trial.

PURPOSE: In the randomized open-label phase III OVHIPEC trial, the addition of hyperthermic intraperitoneal chemotherapy (HIPEC) to interval cytoreductive surgery (CRS) improved recurrence-free and overall survival in patients with stage III ovarian cancer. We studied the cost effectiveness of the addition of HIPEC to interval CRS in patients with ovarian cancer. PATIENTS AND METHODS: We constructed a Markov health-state transition model to measure costs and clinical outcomes. Transition probabilities were derived from the OVHIPEC trial by fitting survival distributions. Incremental cost-effectiveness ratio (ICER), expressed as euros per quality-adjusted life-year (QALY), was calculated from a Dutch societal perspective, with a time horizon of 10 years. Univariable and probabilistic sensitivity analyses were conducted to evaluate the decision uncertainty. RESULTS: Total health care costs were €70,046 (95% credibility interval [CrI], €64,016 to €76,661) for interval CRS compared with €85,791 (95% CrI, €78,766 to €93,935) for interval CRS plus HIPEC. The mean QALY in the interval CRS group was 2.12 (95% CrI, 1.66 to 2.64 QALYs) and 2.68 (95% CrI, 2.11 to 3.28 QALYs) in the interval CRS plus HIPEC group. The ICER amounted to €28,299/QALY. In univariable sensitivity analysis, the utility of recurrence-free survival and the number of days in the hospital affected the calculated ICER most. CONCLUSION: On the basis of the trial data, treatment with interval CRS and HIPEC in patients with stage III ovarian cancer was accompanied by a substantial gain in QALYs. The ICER is below the willingness-to-pay threshold in the Netherlands, indicating interval CRS and HIPEC is cost effective for this patient population. These results lend additional support for reimbursing the costs of treating these patients with interval CRS and HIPEC in countries with comparable health care systems.