Table 3.

Risk of bias and confounding (1: low risk of bias and confounding. 2: unclear risk of bias and confounding. 3: high risk of bias and confounding)

	Random	Allocation	Performance	Detection	Attrition	Reporting	Other	Age	Sex	Tumor	Single or	Location	Surgery	Chemotherapy-	PS
	seq	concealment	bias	bias	bias	bias	bias			Location	multiple	of mets	sites	Previous
	generation										mets			treatment
Cowles et al. 1982	3	3	3	3	3	3	3	1	1	1	1	1	1	1	3
Anderson et al. 1992	3	3	3	3	3	3	3	1	1	1	1	2	1	3	3
Dodd et al. 1999	3	3	3	3	3	3	3	1	1	1	3	1	2	2	1
Otto et al. 2001	1	1	1	1	1	2	2	1	1	1	1	1	1	1	3
Mahmoud-Ahmed et al. 2002	3	3	3	3	2	3	3	1	1	1	1	3	2	3	3
Sweeney et al. 2003	1	1	1	1	1	1	2	1	1	2	3	1	1	2	3
Siefker-Radtke et al. 2004	3	3	3	3	2	2	3	1	1	1	3	1	1	3	3
Kim et al. 2004	3	3	3	3	3	2	2	1	1	1	3	1	1	2	3
Lehmann et al. 2009	3	3	3	3	3	2	1	1	1	1	3	1	1	3	1
Kanzaki et al. 2010	2	3	2	2	2	3	3	1	1	1	1	1	1	1	3
Fokas et al. 2010	1	1	1	1	2	1	2	3	1	1	1	1	1	3	3
Matsuguma et al. 2011	3	3	3	2	3	2	2	1	1	1	2	1	1	3	3
Han et al. 2012	2	3	3	2	3	3	2	1	1	1	1	1	1	3	3
Abe et al. 2013	3	3	3	3	3	3	2	1	1	1	1	1	1	2	3
Bekku et al. 2013	3	3	3	3	3	2	2	1	1	1	1	1	1	2	3
Kim et al. 2015	3	3	3	3	3	2	2	1	1	1	1	1	1	1	3
Necchi et al. 2015	3	3	2	2	3	1	2	1	1	1	1	1	1	1	1