Chi 2006.

Study characteristics
Methods	Retrospective study
Participants	Women with stage IIIC epithelial ovarian cancer The median age at study entry was 60 years (range: 22 to 87) All women presented with FIGO stage IIIC: 465 (100%) Tumour cell type: serous 331 (72%), endometrioid: 57 (12%), clear cell: 22 (5%), mixed: 53 (11%) Tumour grade: 1: 13 (3%), 2: 90 (19%), 3: 339 (73%), unknown: 23 (5%) Ascites: median 1600 mL (range: 0 to 17,000 mL), presence of ascites (N = 429): no = 58 (14%); yes = 371 (86%)
Residual disease details	Type of surgeon: gynaecologic oncologist Options for residual disease on the standardised operative form were as follows: NMRD: 67 (14.4%) Gross residual disease < 0.5 cm: 70 (15.1%) SVRD of 0.6 cm to 1.0 cm: 99 (21.3%) LVRD of 1 cm to 2 cm: 53 (11.4%) LVRD > 2.0 cm: 176 (37.8%) Optimal is defined in 2 ways as NMRD and SVRD (< 1 cm), suboptimal defined as LVRD (> 1 cm) Postoperative chemotherapy records were available in 440/465 (95%) women. Of these 440 women, 426 (97%) were treated with primary platinum‐based systemic chemotherapy with the intent to treat with at least 6 cycles.
Outcomes	Three women (0.6%) died within 30 days of surgery Overall survival: HR adjusted for age and ascites using Cox model: SVRD (< 1 cm) vs NMRD HR 2.07 (95% CI 1.23 to 3.46) LVRD (> 1 cm) vs NMRD HR 3.70 (95% CI 2.27 to 6.04)
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): low risk Valid and reliable measurement of RD Outcome level assessment: Outcome: overall survival 4. Outcome measurement (a‐c): low risk Valid and reliable measurement of outcome 5. Adjustment for other prognostic factors (a‐g): unclear risk HR for OS was adjusted for residual disease, age and ascites in a multivariable Cox model 6. Statistical analysis and reporting (a‐d): high risk No conceptual framework; unclear of variable selection criteria in multivariate model Outcome: progression‐free survival Not reported
Notes	Median follow‐up: 38 months (range: 1 to 199 months) 17‐year death rate: 'Optimal' group: 105/236 'Suboptimal' group: 188/229 Median overall survival in relation to the 5 residual disease categories was: NMRD: 106 months; gross < 0.5 cm: 66 months; 0.6 cm to 1.0 cm: 48 months; 1 cm to 2 cm: 33 months; and > 2 cm: 34 months