PURPOSEThis study aimed to assess long-term follow-up after chemoresection with mitomycin (MMC), a nonsurgical treatment modality for recurrent nonmuscle invasive bladder cancer (NMIBC). At the time of recurrence, chemoresection has previously been shown to reduce the number of patients requiring a procedure (transurethral resection of bladder tumors [TURBT] or office biopsy) by more than 50%. This study investigated the number of patients requiring a procedure during initial treatment and 2-year follow-up in patients treated with short-term, intensive chemoresection with MMC compared with patients undergoing standard surgical treatment of recurrent NMIBC.METHODSA randomized, controlled trial was conducted in two urological departments in Denmark from January 2018 to August 2021. In total, 120 patients with a history of Ta low- or high-grade NMIBC were included upon recurrence. The intervention group received intravesical MMC (40 mg/40 mL) three times a week for 2 weeks and TURBT or office biopsy only if the response was incomplete. The control group received TURBT or office biopsy and 6 weekly adjuvant instillations. The primary outcome was the number of patients undergoing a procedure within 2 years from inclusion, which was compared between groups using the chi-squared test. Recurrence-free survival was analyzed using the Kaplan-Meier method.RESULTSSignificantly fewer patients were in need of a procedure in the intervention group than in the control group: 71% (95% CI, 57 to 81) and 100% (95% CI, 94 to 100), P <.001. The 12-month recurrence-free survival was 36% (95% CI, 24 to 50) and 43% (95% CI, 30 to 56) in the intervention and control groups, respectively (P =.5).CONCLUSIONShort-term intensive chemoresection is an effective treatment strategy for recurrent NMIBC that leads to a reduced number of required procedures without compromising long-term oncological safety.