Rintala 1991.

Methods	Study design: multicentre, prospective, randomised clinical trial Number of study centres: unclear Study dates: 1984–1987, for a subgroup of participants there is a follow‐up of 20 years Participants randomly assigned: 89
Participants	Inclusion criteria: people with Cis grade 1–3 frequently recurrent Ta‐T1 papillary transitional cell cancer grade 1–3 histologically confirmed malignancy or 3 consecutive malignant cytological findings, or both Exclusion criteria: not reported.
Interventions	Group A: BCG Pasteur Strain F, 75 mg Group B: MMC 20–40 mg (AUC method) Procedure: instillations (for 2 hours) started 2 weeks after TUR. Weekly repetition during the first month, then once a month for 2 years.
Outcomes	Recurrence rate, recurrence index, overall mortality, progression, disease‐specific mortality
Funding sources	Finnish Cancer Foundation, Academy of Finland Paolo Foundation and Research and Science Foundation of Farmos
Declarations of interest	No information reported.
Notes	FinnBladder I study group. Jarvinen reported 20‐year follow‐up data based on a subgroup of participants with TaT1 disease and without Cis (91/109 participants).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Comment: method of randomisation was based on date of birth.
Allocation concealment (selection bias)	High risk	Comment: method of randomisation was based on date of birth.
Blinding of participants and personnel (performance bias) all outcomes	High risk	Comment: no information on blinding. We assumed that there was no blinding and that the outcomes might have been influenced by differences in performance due to a lack of blinding.
Blinding of outcome assessment (detection bias) overall survival	Low risk	Comment: no information on blinding. We assumed that there was no blinding but that the absence of blinding has not affected this objective outcome.
Blinding of outcome assessment (detection bias) recurrence and progression free survival	High risk	Comment: no information on blinding. We assumed that there was no blinding. We assumed that the absence of blinding might have had an effect on the detection and measurement of subjective outcomes.
Blinding of outcome assessment (detection bias) serious and non‐serious adverse effects	High risk	Comment: no information on blinding. We assumed that there was no blinding. We assumed that the absence of blinding might have had an effect on the detection and measurement of subjective outcomes.
Blinding of outcome assessment (detection bias) quality of life	Unclear risk	Outcome not reported.
Incomplete outcome data (attrition bias) Survival outcomes	Low risk	Comment: all participants were considered in the analyses (Group A 44/44, Group B 45/45).
Incomplete outcome data (attrition bias) Adverse effect outcomes	Low risk	Comment: all participants were considered in the analyses (Group A 44/44, Group B 45/45).
Incomplete outcome data (attrition bias) Quality of life outcomes	Unclear risk	Outcome not reported.
Selective reporting (reporting bias)	Unclear risk	Comment: no study protocol available.
Other bias	Low risk	Comment: we assumed that there was no risk for other bias.