Exploratory study of olaparib combined with intravesical perfusion in the treatment of secondary bladder cancer after kidney transplantation: preliminary observations and discussion

The incidence of bladder cancer after kidney transplantation is high, but there is a lack of ideal treatment options.This study is an exploratory case series aiming to preliminarily observe the clinical manifestations and safety profile of Olaparib combined with intravesical perfusion in treating secondary bladder cancer post-kidney transplantation, so as to generate scientific hypotheses for subsequent research. This is a single-center preliminary study that analyzed the clinical data of 7 patients with secondary bladder cancer after kidney transplantation who received Olaparib combined with intravesical perfusion therapy. Seven patients with secondary bladder cancer after kidney transplantation were enrolled. Pathologically, 6 cases were high-grade non-muscle-invasive bladder cancer, and 1 case was small cell carcinoma complicated with high-grade non-invasive bladder cancer. Genetic testing showed 4 patients carried Homologous Recombination Repair (HRR) gene mutations, while 3 were negative. All received Olaparib combined with intravesical chemotherapy. Only descriptive follow-up was performed to monitor treatment responses, progression-free survival (PFS), and adverse events (AEs). The median PFS of all patients was 15.8 months, with 15.7 months in HRR-mutated patients and 16 months in non-mutated ones. Tumor recurrence occurred in Patient 1 (20 months post-treatment) and Patient 7 (14 months post-treatment). Patient 4 discontinued Olaparib at 18 months without metastasis or recurrence during follow-up. All patients had varying drug-related AEs, but no Grade 4/5 severe events were reported, and renal allograft function remained normal throughout the study. Olaparib combined with intravesical perfusion showed certain disease control effects in these 7 patients. However, limitations including small sample size, lack of a control group, and no predefined endpoints resulted in insufficient statistical power, so the findings are preliminary and hypothesis-generating.