Table 1. Quality score of studies included.

Study	Randomization	Blinding	Withdrawal/lost to follow-up	Total
Attal 2006 [18]	2	0	0	2
Barlogie 2006 [13,14]	1	0	1	2
Spencer 2009 [19]	2	0	1	3
Stewart 2010(Abstract)[20]	1	0	0	1
Morgan 2012 [22]	2	0	1	3
Maiolino 2012 [21]	1	0	1	2
McCarthy 2012 [8]	2	0	1	3
Attal 2012 [7]	1	1	1	3