NCT01920269.

Methods	Randomised parallel open‐label trial.
Participants	Inclusion criteria Histologically confirmed primary stage pTa‐pT1 urothelial bladder cancer. Adequate bone‐marrow reserve (i.e. white‐blood‐cell count ≥ 4000 × 106 cells/L; platelet count ≥ 120 × 109/L). Normal renal function (i.e. serum creatinine ≤ 123.76 μmol/L). Normal liver function (i.e. serum glutamic‐oxaloacetic aminotransferase ≤ 42 U/L, serum glutamic‐pyruvic aminotransferase ≤ 48 U/L and total bilirubin ≤ 22 μmol/L). Eastern Cooperative Oncology Group performance status between 0 and 2. Exclusion criteria Non‐urothelial carcinomas of the bladder. Previous or concomitant grade G3 urothelial or carcinoma in situ of the bladder, or both. Urothelial carcinoma of the upper urinary tract and urethra, or both. Previous intravesical treatment with chemotherapeutic and immunotherapeutic drugs. Known allergy to mitomycin. Bladder capacity < 200 mL. Untreated urinary tract. Infection; severe systemic infection (i.e. sepsis). Treatment with immunosuppressive drugs. Urethral strictures that would prevent endoscopic procedures and catheterisation. Previous radiotherapy to the pelvis. Other concurrent chemotherapy, radiotherapy and treatment with biological response modifiers. Other malignant diseases within 5 years of trial registration (except for adequately treated basal‐cell or squamous‐cell skin cancer, in situ cervical cancer). Pregnancy. Any factors that would preclude study participation.
Interventions	Group A Transurethral resection alone: participants underwent urinary cytology, random cold‐cup biopsies of the bladder and prostatic urethra, and complete transurethral resection of all bladder tumour visible on endoscopy, ensuring muscle is included in resected samples. Group B Intravesical MMC‐PD after TURBT: mitomycin 40 mg dissolved in 50 mL sterile water is infused intravesically through a Foley catheter, retained in the bladder for 60 minutes with catheter clamping, and then drained. Participants who had a complete response to the initial 6 weekly treatments underwent a further 10 monthly instillations, with the same dose and methods of infusion as initial assigned treatment. Group C Intravesical electromotive mitomycin after TURBT: mitomycin 40 mg dissolved in 100 mL water is instilled and retained in the bladder for 30 minutes with 20 mA pulsed electric current, and then drained. Participants who had a complete response to the initial 6 weekly treatments underwent a further 10 monthly instillations with the same dose and methods of infusion as initial assigned treatment. Response to treatment will be assessed with cystoscopy, biopsy and urinary cytology at 3‐month intervals for 2 years, 6‐month intervals for 3 years and yearly thereafter.
Outcomes	Primary outcome Disease‐free interval (time frame: 120 months). Time from randomisation to first cystoscopy noting recurrence as recorded by pathological assessment of transurethral‐resection samples or biopsy samples. Secondary outcome Time to progression (time frame: 120 months). Time from randomisation until the onset of muscle invasive disease as recorded by pathological assessment of transurethral‐resection samples or biopsy samples. Overall survival (time frame: 120 months). Time from randomisation until death from any cause. Disease‐specific survival (time frame: 120 months). Time from randomisation until death from bladder cancer.
Notes	ClinicalTrials.gov Identifier: NCT01920269. This study has been completed, but the results have not published.

EMDA: electromotive drug administration; MMC‐PD: passive diffusion of mitomycin C; TURBT: transurethral resection of bladder tumour.