A20 OLCSG1c.

Methods	RCT: 1982 to 1987
Participants	28 patients Stage II
Interventions	surgery vs surgery + chemotherapy 1 cycles of chemotherapy cisplatin 80 mg/m2 tegafur 600‐800 mg/m2, daily treatment > 1 year Complete resection
Outcomes	Overall survival
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Data checks on IPD provided suggest adequate sequence generation
Allocation concealment (selection bias)	Low risk	Central randomisation
Selective reporting (reporting bias)	Low risk	IPD supplied for outcomes
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Trial not blinded due to nature of intervention, outcome not likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Trial not blinded due to nature of intervention, primary outcome not likely to be influenced by lack of blinding