Study on prevention of recurrence in patients with NMIBC for whom BCG vaccine treatment failed by hematoporphyrin intravesical perfusion photodynamic therapy (PDT) combined with intravesical perfusion therapy.

Abstract

e16592 Background: To explore the efficacy and safety of hematoporphyrin intravesical perfusion PDT eracombined with intravesical perfusion therapy in preventing recurrence in patients with NMIBC for whome bacillus Calmette-Guérin (BCG) treatment failed. Methods: For patients with NMIBC for whom BCG instillation failed and who refused radical cystectomy, 1-3 treatments of hematoporphyrin intravesical perfusion were administered during the recurrence-free interval (RFI) after TURBT. The specific protocol was as follows: 50-75 mg of hematoporphyrin perfusion was instilled into the bladder with 30 ml of saline, retained for 120 minutes, and then PDT was performed with a light source wavelength of 660 nm and an output power of 600-1800 W. The bladder volume was 150/300 ml, and the irradiation time was 26/50 minutes, with a light dose of 15-20 J/cm². After PDT, 18 patients continued BCG instillation treatment, and 11 patients continued intravesical chemotherapy. Bladder endoscopy, pelvic CT/MRI, and urine cytology were routinely rechecked every 3 months. The primary end points were the recurrence-free survival rate (RFS) at 3, 6, 12, 18 and 24 months, the progression-free survival (PFS) rate, and AEs. Results: From August 2016 to July 2024, a total of 29 patients with NMIBC for whom BCG treatment failed were enrolled. Among them, 21 were T1 patients and 8 were Ta patients. 4 cases were low-grade urothelial carcinoma and 25 were high-grade urothelial carcinoma, including 4 cases of high-grade urothelial carcinoma with carcinoma in situ and 1 case of high-grade urothelial carcinoma with squamous differentiation. 4 cases were intermediate-risk and 25 were high-risk. The median follow-up time was 34.2 months (4.9 - 100.1 months). 2 patients had bladder cancer progression and metastasis, and one patient died. The 3, 6, 12, 18 and 24 month RFS rate were 86.2%, 79.3%, 75.9%, 72.4% and 72.4%. Stratified analysis showed that the 3-24-month RFS rate was 100% for patients who received 2-3 times of PDT during the RFI. The PFS rate was 93.1%. 1 patient chose total cystectomy, and the bladder preservation rate was 96.5%. 7 patients experienced mild urinary discomfort symptoms (7/24 = 24.1%), mainly manifested as dysuria and frequent urination, and most of them relieved within 1-4 weeks after PDT. No severe bladder spasm or systemic photosensitivity reactions were observed. Conclusions: For patients with NMIBC for whom BCG instillation failed, hematoporphyrin intravesical perfusion combined with PDT has significant therapeutic effects and good safety. Especially for those who received multiple treatments during the RFI, no recurrence or progression was observed within 2 years. Further randomized controlled studies are warranted.