Robertson 1998.

Methods	Location of trial: UK Number of centres: multicentre (4) Funding: not stated Trial ID: not stated
Participants	Inclusion criteria: resectable, stage T2–T4, N0–N2, M0 head and neck tumours Exclusion criteria: stage I (T1N0M0); history of malignancy, apart from basal cell carcinoma of the skin, or intraepithelial carcinoma of the cervix Recruitment period: December 1991 to December 1993 Number randomised: 35 (intended 350 but trial stopped early due to concern of the number of deaths in the RT alone arm) (33/35 OC: 40% tongue, 43% FOM, 11% RMT, 6% tonsil) Number analysed: 35
Interventions	Surgery + RT vs RT alone Group 1 (n = 17): radical resection and ND + PORT. Radical surgery involved wide local excision of the primary tumour with 1 cm margin. A radical or functional ND was carried out at the same time at the discretion of the surgeon. Reconstruction of the oral cavity was carried out immediately. PORT comprised 60 Gy in 30 fractions over 6 weeks, commencing within 6–8 weeks of surgery. Group 2 (n = 18): RT alone; 66 Gy in 33 fractions over 6.5 weeks, receiving 2 Gy per day
Outcomes	Primary: overall survival, disease‐free interval, recurrent disease, locoregional control Secondary: adverse events Duration of follow‐up: 3 years
Notes	HR data taken from Kaplan‐Meier graph (no numbers at risk). Data presented in Kaplan‐Meier estimates for DFS, but not used as graph started at 50% for RT alone arm. Authors provided additional information relating to allocation concealment and the characteristics of tumours.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Random permuted blocks of four were used for randomization" following stratification according to institution and site of primary disease.
Allocation concealment (selection bias)	Low risk	Randomisation via a telephone call to the West of Scotland Clinical Trials Office.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Mortality was primary outcome and considered an objective outcome.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting of outcomes.
Other bias	High risk	Anticipated enrolment of 350 participants, but trial stopped after 35 participants recruited because clinicians felt it was unethical to continue. Appropriate procedures and analysis were conducted. More than half of participants recruited had either delays or interruptions to the planned RT schedule. It is likely that this would have had a greater effect on the outcomes of the RT alone arm of this trial.