Table 3

Methodological quality of included trials

Study	Allocation concealment	Method of randomisation	Blinded assessment of outcome	Description of withdrawals	Intention to treat analysis
*Unclear if losses to follow up.
†Confirmed by contacting authors.
‡RTOG, Radiation Therapy Oncology Group.
§Investigators undertaking follow up blinded from treatment group.
MRC, UK²⁵	Adequate	Not reported	None described	No description	Yes*
NCI, USA²⁷	Adequate	Not reported	None described	Yes	Yes
National Cancer Institute of Canada trial, North America²⁶	Adequate†	Adequate†	No	No losses†	Yes†
RTOG‡ 89–01¹⁷	Not reported	Not reported	None described	Incomplete description	No
University of Athens, Greece¹⁶	Not reported	Not reported	None described	No description	No
Intergroup 0139 trial (RTOG‡93–09), North America²⁰	Not reported	Not reported	None described	Incomplete description	No
Yamaguchi University(VATS v open)²⁴	Inadequate	Inadequate	None described	No losses†	No
Lung Cancer Study Group trial,North America²²	Adequate	Not reported	None described	Yes (N.B. 18% loss in each group)	Unclear
University of Munich¹³	Adequate†	Adequate	Yes§	Yes	No
Yamaguchi University¹⁴	Adequate†	Adequate	None described	Yes	Yes
Sun Yat-Sen University of Medical Sciences, Guangzhou¹⁵	Adequate†	Adequate†	None described	Yes	No