The efficacy and safety of interval and post-reTURBT intravesical therapy for bladder cancer.

Re-transurethral resection of bladder tumors (reTURBTs) improves staging and local control in high-risk bladder cancer, posing the clinical challenge of determining the most effective adjuvant intravesical regimen. In this multicenter retrospective study, 174 patients undergoing reTURBT between 2010 and 2024 received either Bacillus Calmette-Guérin (BCG) or pirarubicin/epirubicin (THP/EPI) intravesical therapy, delivered as post-reTURBT instillations alone (PIT) or combined with interval instillations before and after reTURBT (IIT + PIT). We compared recurrence-free survival (RFS) and adverse events across regimens and performed subgroup analyses by tumor characteristics. IIT + PIT significantly prolonged RFS: BCG IIT + PIT conferred a 2.93-fold lower recurrence risk versus BCG PIT (p = 0.03), while THP/EPI IIT + PIT achieved a 2.61-fold reduction versus THP/EPI PIT (p < 0.001). The greatest benefit appeared in high-grade, cT1 lesions. Our findings endorse IIT + PIT-particularly with BCG-as an effective strategy to reduce recurrence in high-risk bladder cancer.