Short-term outcomes of intravesical gemcitabine for non-muscle-invasive bladder cancer after recent approval for use in Korea

In high-risk non-muscle-invasive bladder cancer (NMIBC), intravesical Bacillus Calmette-Guérin (BCG) is the standard adjuvant therapy post-transurethral resection of bladder tumor (TURBT). Intravesical gemcitabine, used as an alternative or second-line therapy amid BCG shortages, lacks outcome studies in the Korean population. Patients who received weekly intravesical gemcitabine for 6 weeks after TURBT from 2019 to 2022 were retrospectively investigated. Based on the American Urological Association risk classification, patients with high- or very high-risk NMIBC who refused cystectomy were included. Maintenance treatment was performed depending on their risk. Recurrence was defined as histologic confirmation on subsequent cystoscopic biopsies or TURBT. Disease free survival (DFS) was evaluated by the Kaplan-Meier method. The study included 60 patients, comprising 45 high-risk (group 1) patients with a median age of 76 years and 15 very high-risk (group 2) patients with a median age of 68 years. Among them, 28 patients had previously received intravesical BCG. Over a median follow-up of 22 months, recurrence occurred in 31 patients in group 1 and 11 in group 2. The DFS rates of the high-risk group and the very high-risk group were 57.8% versus 40% at 1 year, 20.7% versus 21.3% at 2 years and 20.7% versus 21.3% at 3 years, respectively (p=0.831). Tis stage (p=0.042) and prostatic urethra invasion (p=0.028) were significant predictors of DFS. Cancer-specific mortality rates were 2.2% in group 1 and 6.7% in group 2 (p=0.441). Similar DFS outcome between high-risk and very high-risk patients were observed based on short-term results in Korea. This finding is crucial for clinical practice; however, studies analyzing more patients and long-term outcomes are needed.