Comparing efficacy and safety of in-house gemcitabine to mitomycin for bladder instillation in intermediate-risk NMIBC.

INTRODUCTION: Intermediate-risk (IR) Non-Muscle Invasive Bladder Cancer (NMIBC) is associated with a high rate of tumor recurrence. To improve patient outcomes, it is recommended to use adjuvant intravesical therapy, by mitomycin C (MMC) or Bacillus Calmette Guerin (BCG). Gemcitabine (GMC) is a known molecule used in urothelial cancer. We aimed to study the efficacy and safety profile of a gemcitabine solution, compared to mitomycin C, in the treatment of IR NMIBC.

MATERIAL: In this retrospective study, patients with IR NMIBC treated between 2016 and 2020 were selected from two participating centers using either gemcitabine (center A) as the intravesical chemotherapy regimen or mitomycin C (center B). The primary endpoint was recurrence rate and secondary end points were treatment interruption and its causes.

RESULTS: In our cohort of 102 IR NMIBC patients, 49 patients received GMC and 53 MMC with a median follow-up of 30 months. Overall recurrence rate was 42.1% with 22.4% in the GMC group and 60.3% in the MMC group (P<0.01). This difference was also found in the multifactorial analysis. Course interruption was observed in 14.7% of all patients, primarily attributed to adverse events (46.6%), without difference between groups.

CONCLUSION: Adjuvant intravesical gemcitabine in patients with IR NMIBC seems to be an interesting option associated with a lower tumor recurrence rate and a favorable tolerance profile when compared to MMC. Larger scale prospective randomized trials are needed to validate our findings.

LEVEL OF EVIDENCE: III.