Bixel 2020.

Study characteristics
Methods	Retrospective analysis of past medical data from The Ohio State University Wexner Medical Center and Duke University Health System between January 2004 and April 2017 Multicentre study USA
Participants	134 patients diagnosed with stage III to IV ovarian, fallopian tube or primary peritoneal cancer Median age (range): 64.3 (21 to 87) Median BMI (range): 28.1 (16 to 52.5) Ethnicity: 110 white (82%) FIGO III: 49 (36%) FIGO IV: 54 (40%) FIGO stage not otherwise specified but considered advanced: 31 (24%) Serous histology: 112 (83%) Tumour grade 1: 3 (2%) Tumour grade 2: 123 (92%) Tumour grade unknown: 8 (6%)
Residual disease details	Women underwent interval debulking surgery Optimal RD defined as RD ≤ 1 cm NMRD: 89 (66%) SVRD: 45 (34%)
Outcomes	Overall survival Median OS: 35.3 (95% CI 28.6 to 42.9) There was no multivariate model for overall survival despite there being progression‐free survival Progression‐free survival Disease recurrence: 117 (87%) Median PFS: 12.2 (95% CI 11.3 to 13.7) After controlling for NACT cycles, route of postoperative chemotherapy administration (intraperitoneal or intravenous), maintenance therapy (yes/no); residual disease (SVRD vs NMRD) (adjusted HR 1.564 (1.055 to 2.287)) 2 (1%) patients died during treatment: 1 patient in the IP group died from a myocardial infarction and 1 patient in the IV group died as a result of sepsis with resulting complications
Risk of bias (QUIPS)	1. Study participation (a‐f): low risk Adequate number of participants and description of target population. Baseline characteristics, eligibility criteria, sampling frame and period/place study took place presented clearly. 2. Study attrition (a‐e): unclear risk Unclear if patients with incomplete follow‐up were excluded before arriving at the stated sample size. Insufficient information to permit judgement. 3. Prognostic factor measurement (a‐f): unclear risk Adequate cut‐off for residual disease used (< 1 cm). Multicentre design may introduce heterogeneity in measurement of RD Outcome level assessment: Outcome: overall survival 4. Outcome measurement (a‐c): low risk Valid and reliable measurement of OS 5. Adjustment for other prognostic factors (a‐g): high risk OS was reported in KM curve but was not used in any multivariable modelling 6. Statistical analysis and reporting (a‐d): high risk There was only a multivariate model for PFS but not OS Outcome: progression‐free survival 4. Outcome measurement (a‐c): low risk Valid and reliable measurement of PFS 5. Adjustment for other prognostic factors (a‐g): high risk Model for PFS adjusted for NACT cycles, route of administration (IP or IV), maintenance therapy. However, none deemed to be critically important prognostic factors. 6. Statistical analysis and reporting (a‐d): high risk No conceptual framework; data driven based on P values of univariate associations. Unclear if multivariate Cox was used as logistic regression mentioned in methods but hazard ratios reported. There was only a multivariate model for PFS but not OS.
Notes	37 (28%) patients receiving IP and 97 (72%) patients receiving IV chemotherapy Median NACT cycles: 3 (range 1 to 6) NACT regime Platinum/taxane: 133 (99%) Platinum/other: 1 (1%) Adjuvant chemotherapy regime Platinum/taxane: 122 (91%) Platinum/other: 3 (2%) Non platinum: 9 (7%) Adjuvant chemotherapy cycles: Intraperitoneal group: median 4 (range 2 to 6) Intravenous group: median 3 (range 1 to 6) Maintenance therapy following completion of planned chemotherapy: 10 (7%) At the time of surgery, 32 (24%) patients underwent a bowel resection and 15 (11%) underwent extensive upper abdominal debulking procedures