Primary chemotherapy versus primary surgery for newly diagnosed advanced ovarian cancer (CHORUS): an open-label, randomised, controlled, non-inferiority trial

Summary Background The international standard of care for women with suspected advanced ovarian cancer is surgical debulking followed by platinum-based chemotherapy. We aimed to establish whether use of platinum-based primary chemotherapy followed by delayed surgery was an effective and safe alternative treatment regimen. Methods In this phase 3, non-inferiority, randomised, controlled trial (CHORUS) undertaken in 87 hospitals in the UK and New Zealand, we enrolled women with suspected stage III or IV ovarian cancer. We randomly assigned women (1:1) either to undergo primary surgery followed by six cycles of chemotherapy, or to three cycles of primary chemotherapy, then surgery, followed by three more cycles of completion chemotherapy. Each 3-week cycle consisted of carboplatin AUC5 or AUC6 plus paclitaxel 175 mg/m2 , or an alternative carboplatin combination regimen, or carboplatin monotherapy. We did the random assignment by use of a minimisation method with a random element, and stratified participants according to the randomising centre, largest radiological tumour size, clinical stage, and prespecified chemotherapy regimen. Patients and investigators were not masked to group assignment. The primary outcome measure was overall survival. Primary analyses were done in the intention-to-treat population. To establish non-inferiority, the upper bound of a one-sided 90% CI for the hazard ratio (HR) had to be less than 1·18. This trial is registered, number ISRCTN74802813, and is closed to new participants. Findings Between March 1, 2004, and Aug 30, 2010, we randomly assigned 552 women to treatment. Of the 550 women who were eligible, 276 were assigned to primary surgery and 274 to primary chemotherapy. All were included in the intention-to-treat analysis; 251 assigned to primary surgery and 253 to primary chemotherapy were included in the per-protocol analysis. As of May 31, 2014, 451 deaths had occurred: 231 in the primary-surgery group versus 220 in the primary-chemotherapy group. Median overall survival was 22·6 months in the primary-surgery group versus 24·1 months in primary chemotherapy. The HR for death was 0·87 in favour of primary chemotherapy, with the upper bound of the one-sided 90% CI 0·98 (95% CI 0·72–1·05). Grade 3 or 4 postoperative adverse events and deaths within 28 days after surgery were more common in the primary-surgery group than in the primary-chemotherapy group (60 [24%] of 252 women vs 30 [14%] of 209, p=0·0007, and 14 women [6%] v