Lawrence 1974.

Methods	Location of trial: US. Number of centres: 1. Funding: not stated. Trial ID: not stated.
Participants	Inclusion criteria: previously untreated Stage II‐IV squamous cell carcinoma of oral cavity, oropharynx, or pharynx with technically resectable disease. Exclusion criteria: Stage I cancer (usually treated by radiation therapy alone), patients with other cancers, including lip, paranasal sinus, nasopharynx, or glottic carcinoma of larynx. Recruitment period: January 1969 to December 1972. OC: 64/143 (45%). OP: 37/143 (26%). OC+OP: 101/143 (71%). Number randomised: 143. Number analysed: 143.
Interventions	Pre‐operative radiotherapy plus surgery versus surgery alone Pre‐operative radiotherapy (n = 69): 2 fractions each of 1.4 Gy given 48 and 24 hours prior to surgery. RT delivered by Co‐60 unit using 80 cm source skin distance followed by radical resection of primary carcinoma and simultaneous radical neck dissection. Surgery alone (n = 74): radical resection of primary carcinoma & simultaneous unilateral or bilateral radical neck dissection.
Outcomes	Primary: surgical complications. Secondary: overall survival, local recurrence. Duration of follow‐up: 4 years.
Notes	Unable to use data.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	"Patients...randomly assigned". Randomisation stratified by site of primary tumour and stage of disease, but method of sequence generation not described.
Allocation concealment?	Unclear risk	Insufficient information.
Blinding ‐ Outcome Assessors	High risk	Not mentioned.
Incomplete outcome data addressed?	Low risk	All randomised patients are included in the analyses.
Free of selective reporting?	Low risk	Important outcomes of surgical complications, mortality and local recurrence reported.
Free of other bias?	Low risk	Groups appear comparable at baseline. No other apparent bias.