Study	Reason for exclusion
Alberts 1993	No survival analysis by RD as all patients had suboptimal surgery (defined as more than 2 cm)
Alberts 1996	No multivariate analysis data
Alphs 2006	Included only 78 patients; 8 patients were early‐stage and 9 patients received NAC
Altman 2012	No multivariate analysis data
Andersen Soegaard 2005	This study included only 83 patients, of which 66 received platinum‐based chemotherapy. No multivariate analysis was performed.
Anuradha 2016	Scope of study focused on time interval between surgery and chemotherapy
Bailey 2006	Chemotherapy data are absent
Baker 1994	95% CI or SE (HR) are not reported and the HR point estimate for OS is 1.66 across all categories; it is not clear if the < 1 cm category was used as the reference group when compared to both 1 cm to 2 cm and > 2 cm residual disease
Barda 2004	27.3% of ovarian cancer received non‐platinum chemotherapy
Benedetti‐Panici 1996	Included only 66 patients and stage IIb. No survival data per RD. Also included NAC/IDS.
Bertelsen 1990	Study does not include a multivariate analysis
Bertelsen 1993	No survival data per residual disease
Bian 2016	No multivariate analysis data
Bonnefoi 1999	38 patients had NAC and 27 patients had non‐platinum chemotherapy
Brinkhuis 1996a	No direct comparison by size of residual disease and there is no multivariate analysis
Brinkhuis 1996b	1 group of patients did not receive platinum chemotherapy except at progression. Survival data per RD is reported for all patients collectively.
Bristow 1999	Included only 84 patients
Cai 2007	Included 95 patients. We suspect that IDS cases were included.
Ceresoli 2018	Included only 56 patients at analysis, of which 28 treated with cytoreductive surgery + HIPEC and 28 treated with cytoreductive surgery alone.
Chekman 2015	Did not report outcomes for extent of residual disease by type of initial primary surgery
Clamp 2018	No multivariate analysis data
Colozza 1997	Included only 39 patients
Conte 1991	No survival data per residual disease
Conte 1996	There is no optimal group. No survival data per residual disease.
Crawford 2005	18% of the cases were stage IC and II
Creasman 1990	All cases were sub‐optimal, defined as RD greater than 1 cm; no analysis by RD
Cummins 2019	Full text unavailable
Dao 2016	Included patients who had neoadjuvant chemotherapy
Del Campo 1994	Included only 91 patients
de Oliviera 1990	1 arm did not receive platinum‐based chemotherapy
di Re 1996	14 patients had borderline tumours. Also included stage II cases. Before 1979, patients received non‐platinum chemotherapy.
Elgamal 2019	Full text unavailable
Fagotti 2020	Did not report outcomes for extent of residual disease by type of initial primary surgery
Gao 2001	Only 31 cases
Gasimli 2016	Included selective group of women with cytoreduction of tumour to microscopic optimal disease (0 cm)
Geisler 2004	24 patients were stage I and II
Gershenson 1989	Included only 50 patients
Gershenson 1992	All patients were optimal, defined as RD less than 2 cm. No further analysis of survival by RD.
Gershenson 1995	Included only 51 patients
Greggi 2016	RD thresholds were not part of scope as the study focused on comparison of oncology specialist centres versus non‐specialist centres
Grem 1991	Included only 43 patients
Hainsworth 1990	Included only 25 patients
Hakes 1992	Included only 78 patients
Hamid 2002	Only included 62 patients
Hardy 1991	Included only 30 stage IV patients
Heitz 2016	No multivariate analyses were reported
Hoskins 1992	All patients are optimal, i.e. less than 1 cm. Survival data is per preoperative disease volume rather than RD.
Hoskins 1996	Included only 29 patients
Hoskins 1997	No survival by residual disease
Itamochi 2002	Optimal surgery, i.e. size of RD, is not properly defined
Kaern 2005	Included only 31 stage III patients with no control group having RD more than 1 cm
Kehoe 2015	Comparisons of residual disease were based on type of intervention
Kessous 2017	No multivariate analysis data
Keyver‐Paik 2016	No multivariate analyses were reported
Kirmani 1994	Included only 29 patients
Kristensen 1995	Included only 27 patients
Le 1997	Data for stage IIIC and IV subgroup was not reported and authors no longer had access to these data
Lee 2018	No multivariate analyses were reported and no response from corresponding author after request for adjusted estimates
Loizzi 2016	Included only 78 patients
Lorusso 1998	Included only 34 patients
Malik 1998	Included only 21 patients
Marchetti 1993	Included only 70 patients
McGuire 1996	No multivariate analyses were reported
Michaan 2018	Chemotherapy response score not same as optimal cytoreduction
Ngan 1989	Contained 65 patients only and 15 patients were excluded, so only 50 patients
Omura 1989	95% CIs and P values from Cox model in adjusted estimates are not reported. Cannot use Parmar's methods given the number of deaths and log rank P value as we need the unadjusted estimate.
Onda 2020	Did not report outcomes for extent of residual disease by type of initial primary surgery
Palmer 1992	Included only 70 patients
Piver 1991	43 patients did not receive platinum‐based chemotherapy. No multivariate analysis.
Raspagliesi 2018	No multivariate analysis data
Redman 1986	Included 89 patients, 11 of whom initially did not receive platinum chemotherapy
Risum 2012	Only 17 women went through NACT‐IDS
Rodriguez 2013	Comparisons were in terms of surgical procedures performed and could not be analysed by residual disease thresholds
Rose 2004	Reported on outcome after ''secondary'' debulking surgery. However, Winter 2007 included the results of GOG 152 by residual diease after primary cytoreductive surgery. This has been confirmed through personal communication with GOG statistician (Dr Mark Brady).
Ruscito 2016	Study did not distinguish between PDS and IDS
Rutten 2014	17% of sample made up of FIGO I and II
Salani 2007	Case‐control study
Sessa 1991	No multivariate analysis performed
Shapiro 1998	Included only 26 patients
Shinozuka 1999	Some patients received preoperative chemotherapy
Sioulas 2017	Included women who received combination of intravenous/intraperitoneal chemotherapy and RD was not adequately reported in multivariate analyses
Skarlos 1996	Included patients with stage IIC disease
Smits 2015	Scope of study focused on obese and non‐obese patients and included proportion of women who received neoadjuvant chemotherapy
Solmaz 2015	Did not report survival by residual disease
Son 2017	Included only 60 patients
Stewart 2015	Full text unavailable
Stewart 2016	No multivariate analysis
Strauss 1996	Included 42 patients only
Suidan 2015	Reported in abstract form only and unlikely that residual disease thresholds were assessed in appropriate multivariate analyses
Sun 2000	Patients who did not receive preoperative chemotherapy are only 76. Nature of chemotherapy received not clear.
Sutton 1989	Included only 56 patients
Takano 2006	Most patients had early‐stage disease, which cannot be separated from late‐staged cases
Takano 2007	Included early‐stage disease (stage IC and II), which cannot be separated from late‐staged cases
Tay 1996	Included 62 patients only. Did not include survival data per optimal versus suboptimal.
Taylor 1994	Included only 64 patients
Tingulstad 2003	6 patients did not receive chemotherapy and 6 patients received non‐platinum chemotherapy
Todo 2003	Included patients who received NAC and IDS but did not report by extent of disease
Trhlík 2013	Full text unavailable
Uyar 2005	18 patients were stage I and II. No survival data per RD.
Vallejos 1997	Included only 30 patients
Van Der Burg 1996	Reported results per residual disease after NAC/IDS
Van Driel 2017	Non‐platinum based chemotherapy was given to all the women
van Vliet 2015	Included patients with who received IDS
Vergote 2010	Comparisons of residual disease were based on type of intervention
Vergote 2018	Comparisons of residual disease were based on type of intervention
Vidal 2016	No multivariate analyses were reported
Wadler 1996	Survival reported per residual disease in all patients including 118 who received non‐platinum chemotherapy
Wallace 2017	No multivariate analyses were reported
Warwick 1995	31 patients were stage II. No survival data per RD.
Willemse 1992	Included only 76 patients
Wils 1990	Included only 88 patients
Wimberger 2007	Multivariate analyses did not include residual disease and the study also included women with stage IIB and IIC disease. We attempted to contact the authors for further information but at time of submission of the review there had been no correspondence.
Yamamoto 2007	Included 67 ''selected'' patients with rare histological subtype
Zang 1999	Included only 71 patients and 31 of them received neoadjuvant chemotherapy
Zhang 2015	< 100 patients with advanced disease in study

CI: confidence interval; HIPEC: hyperthermic intraperitoneal chemotherapy; HR: hazard ratio; IDS: interval debulking surgery; NAC: neoadjuvant chemotherapy; OS: overall survival; PDS: Primary debulking surgery; RD: residual disease; SE: standard error