Nonmuscle-invasive bladder cancer after solid organ transplantation: Clinical outcomes and recurrence patterns

Solid organ transplant recipients face an increased risk of bladder cancer and require lifelong immunosuppression, which may alter the natural history and treatment response of nonmuscle-invasive bladder cancer (NMIBC). Balancing cancer control with allograft preservation complicates clinical decision-making, yet outcome data in this population remain scarce.

A retrospective study of transplant recipients diagnosed with NMIBC post-transplant was conducted. The index date was NMIBC diagnosis. NMIBC recurrence was the primary endpoint, with death before recurrence as a competing event. Recurrence-free survival was estimated using Kaplan-Meier methods, and cumulative incidence of recurrence and competing mortality using the Aalen-Johansen estimator. Cox models evaluated predictors of recurrence.

Fifty-nine transplant recipients met inclusion criteria (median age 68 years; 89.8% male), with high-risk disease present in 40/59 (67.8%). High-grade disease was present in 38/59 patients (64.4%), with T1 stage in 20/59 (33.9%) and concomitant carcinoma in situ in 13/59 (22.0%). Over a median follow-up of 37.4 months, 11/59 patients (18.6%) experienced recurrence at a median of 15.1 months, all among those receiving Bacillus Calmette-Guérin (BCG) induction. The 5-year cumulative incidence for recurrence was 20.4%, compared with 40.5% for competing mortality. Progression to advanced disease (≥pT2 and/or nodal involvement) occurred in 3/59 (5.1%) overall, predominantly within the high-grade subcohort. All-cause mortality was 36/59 (61.0%), with a bladder cancer-specific mortality of 5/59 (8.5%). In univariable models, tumor size >3 cm (HR 19.53, P = 0.005) and increasing age (HR 1.10, P = 0.066) were associated with recurrence. Granular information on specific non-BCG intravesical regimens was limited, precluding analysis of comparative efficacy among alternative agents in this population.

In this single-institution transplant cohort, competing mortality exceeded recurrence risk. Traditional prognostic factors like tumor size predicted recurrence, yet survival was driven by transplant-related comorbidities. These findings support the use of competing-risk methodologies for accurate outcome estimation and highlight the need for individualized, multidisciplinary management in this complex population.