Gemcitabine versus Bacillus Calmette-Guerin for Intravesical Therapy in Treatment-Naïve Low-Grade Intermediate-Risk Non-Muscle Invasive Bladder Cancer

Patients with intermediate-risk (IR) non-muscle-invasive bladder cancer (NMIBC) are recommended to receive induction intravesical chemotherapy or immunotherapy. However, the comparison between gemcitabine and BCG in treatment-naive, low-grade IR-NMIBC patients remains underexplored. This study aims to evaluate the efficacy of gemcitabine compared to BCG in a cohort of treatment-naive IR-NMIBC patients. A retrospective analysis was conducted on patients with low grade IR-NMIBC, classified according to International Bladder Cancer Group criteria, with no prior history of induction intravesical treatment. Patients received either induction intravesical BCG or gemcitabine. Recurrence was defined as histologically confirmed cancer during follow-up, while progression included stage/grade progression. Kaplan-Meier estimates were used for survival analysis, and multivariable Cox analysis identified factors associated with recurrence and progression. Of the 151 patients with IR-NMIBC, 78 received BCG and 73 received gemcitabine. Both groups completed the 6-week induction treatment at similar rates (100%), and maintenance therapy was administered to 47% of BCG patients and 53% of gemcitabine patients (p = 0.46). The median number of maintenance doses was 6 (IQR: 3-9) in the BCG group and 8 (IQR: 4-10) in the gemcitabine group (p = 0.83). Median follow-up was 54 months for patients receiving BCG and 36 months for patients receiving gemcitabine. After adjusting for age, IBCG subgroups, year of treatment, single postoperative instillation, and maintenance therapy, gemcitabine was associated with a higher risk of recurrence compared to BCG (p=0.02), while the risk of progression remained similar between the two groups (p = 0.87). Adverse events were observed in 62 % of patients treated with BCG and 38 % of patients treated with gemcitabine (p = 0.02). Gemcitabine is associated with a higher risk of recurrence than BCG in treatment-naïve IR-NMIBC patients. However, both treatments show comparable efficacy in preventing disease progression.