Fairris 1984.

Methods	Placebo‐controlled (double‐blind), parallel‐group trial Number of centres not stated Period of inclusion not stated
Participants	Inclusion criteria Not stated Exclusion criteria Not stated Baseline data Not stated (n = 6 participants) Withdrawal: no dropouts
Interventions	Intervention A: superficial X‐ray therapy (N = 9 sites) Control intervention B: placebo (N = 9 sites) Co‐interventions: none Duration of treatment: 18 weeks
Outcomes	No primary or secondary outcome pre‐specified Grade of severity at each visit (no precision) Participants were reviewed 6, 9, and 18 weeks after the start of X‐ray therapy. During each visit, patient and observer separately graded severity of the disease at both sites
Notes	Available only as an abstract; hence, many details are missing and some are not clear Funding: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: no indication on randomisation sequence generation
Allocation concealment (selection bias)	Unclear risk	Comment: no indication on the process to guarantee allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: the intervention is radiotherapy on the treated side and placebo on the other side No indication of the measures used to guarantee blinding of participants and personnel
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: the intervention is radiotherapy on the treated side and placebo on the other side. No indication of the measures used to guarantee blinding of outcome assessors
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: no indication on dropout nor on eventual ITT analysis
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol; no primary outcome specified