MacDougall 1990.

Methods	Location of trial: Edinburgh, Scotland. Number of centres: 1. Funding: Medical Research Council, Cancer Research Campaign, Scottish Home and Health Department, Lothian Health Board. Trial ID: not stated.
Participants	Inclusion criteria: previously untreated patients with histologically confirmed squamous cell carcinoma of oral cavity, oropharynx, larynx or hypopharynx, less than 80 years old, deemed fit for radiotherapy. Exclusion criteria: primary tumours with high probability of local control with photon treatment. Recruitment period: 1977 to 1984. OC: 66/165 (40%). OP: 35/165 (21%). OC+OP: 101/165 (61%). Number randomised: 165. Number analysed: 165.
Interventions	Fast neutron radiotherapy versus photon radiotherapy Fast neutron (n = 85): 20 daily fractions over 4 weeks. Total absorbed dose of 15.6 to 16.7 Gy. Photon (n = 80): 20 daily fractions over 4 weeks. Total absorbed dose 54‐56 Gy.
Outcomes	Primary: locoregional control. Secondary: 5 and 10 year survival, disease free survival at 5 years, cause specific survival, late radiation necrosis. Duration of follow‐up: minimum of 5 years, up to 11 years.
Notes	Sample size calculation: based on predicted increase of locoregional control from 40% to 70% it was estimated that 164 patients would be required to show this difference with power of 90% and α = 0.05 on a tow tailed test of significance. Part of multicentre trial but full data from 2 centres not available. Dichotomous data only for outcomes of interest.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	Randomisation stratified on site of primary tumour and presence/absence of malignant lymph nodes. Envelopes containing treatment allocation prepared by trial statistician in Edinburgh, and held by Neutron Clinic secretary.
Allocation concealment?	Low risk	Sequentially numbered sealed envelopes were drawn.
Blinding ‐ Outcome Assessors	High risk	Not mentioned.
Incomplete outcome data addressed?	Low risk	All randomised patients included in analysis.
Free of selective reporting?	Unclear risk	No planned outcomes listed in methods section. Important outcomes reported.
Free of other bias?	Unclear risk	Gender imbalance between the groups, unclear if this would introduce a bias.