Onda 2016.

Study characteristics
Methods	Randomised phase III non‐inferiority study (JCOG0602) conducted in 34 institutions in Japan
Participants	301 women aged 20 to 75 years enrolled with stage III or IV ovarian, tubal and peritoneal cancers diagnosed by clinical findings, imaging studies (CT, MRI and CXR) and cytology of ascites, pleural effusions or tumour centesis
Interventions	PDS followed by 8 cycles of chemotherapy +/‐ additional IDS if not completely debulked prior to commencing chemotherapy compared to 4 cycles of NACT followed by IDS and a further 4 cycles of chemotherapy
Outcomes	Primary outcomes of OS and PFS not reported in this report. Secondary outcomes of adverse events, frequency and duration of surgery, amount of blood loss and frequency of blood, plasma and albumin transfusions. Median cycles of chemotherapy: NACT = 8 (IQR 7 to 8); PDS = 8 (IQR 6 to 8). Other chemotherapy received, details not provided in the paper or supplementary data, but the protocol scheduled chemotherapy was as follows: Carbolpatin (AUC6) and paclitaxel 175 mg/m2 given 3‐weekly for a total of 8 cycles with IDS scheduled after 4 cycles
Notes	49 women randomised to primary debulking arm underwent additional interval debulking surgery
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The JCOG Data Center randomly assigned treatment to each women via a minimisation method with equal probability of assignment to each treatment arm. Balancing factors were institution, stage (III versus IV, performance status (0 to 1 versus 2 to 3) and age (< 60 versus > 60).
Allocation concealment (selection bias)	Low risk	The JCOG Data Center randomly assigned treatment to each women via a minimisation method with equal probability of assignment to each treatment arm
Blinding of participants and personnel (performance bias) All outcomes	High risk	Women and treating physicians were not masked to assigned treatment
Blinding of outcome assessment (detection bias) All outcomes	High risk	Individuals assessing outcomes and analysing data were not masked to assigned treatment
Incomplete outcome data (attrition bias) All outcomes	Low risk	OS and PFS analysed using appropriate statistical methods
Selective reporting (reporting bias)	Low risk	Study recognises that QoL may contribute to measure of treatment invasiveness, but scope was on survival outcomes
Other bias	High risk	Fourteen women (one in PDS and 13 in NACT) underwent some type of surgery (off‐protocol treatment). These off‐protocol surgeries were not included as PDS or IDS in the analysis. Appears to be significantly more in NACT group. No ITT analysis carried out.