Analysis of the relationship between the number of hematoporphyrin intravesical perfusion photodynamic therapy (PDT) combined with intravesical perfusion therapy with tumor recurrence and progression in non-muscle-invasive bladder cancer (NMIBC).

e16591 Background: To understand whether increasing the number of hematoporphyrin intravesical perfusion PDT during the recurrence-free interval (RFI) can reduce the recurrence rate and progression rate of NMIBC. Methods: For NMIBC with a clear diagnosis, in addition to the routine intravesical perfusion Therapy, 1-3 times of hematoporphyrin intravesical perfusion PDT are given during the non-recurrence period. The specific PDT protocol is as follows: 50-75 mg of hematoporphyrin injection + 30 ml of saline for intravesical instillation, retained for 120 minutes, followed by PDT with a light source wavelength of 660 nm and an output power of 1800 W for 26 minutes, with a light dose of 20 J/cm². Then, pelvic CT or MRI, and urine cytology are routinely rechecked every 3 month. The primary end point are 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 total of 86 patients were enrolled. Among them, 58 patients received one intravesical instillation of hematoporphyrin PDT during the RFI (single treatment group), and 28 patients received 2-3 intravesical instillations of hematoporphyrin PDT during the RFI (multiple treatment group). The median follow-up time was 43.2 months (4-100.1). There were no differences between the two groups in terms of age, gender, pathological grade, risk stratification, tumor recurrence score, tumor progression score, whether combined with carcinoma in situ, and the use of BCG (all P > 0.05). The 3, 6, 12, 18 and 24month RFS rates of the single treatment group and the multiple treatment group were 86.2% vs 100% (P = 0.049),, 74.1% vs 100% (P = 0.018), ,67.2% vs 100% (P = 0.0008), 50% vs 92.9% (P < 0.0001), 36.2% vs 89.3% (P < 0.0001) respectively, and all with statistical significance. The PFS rates of the single treatment group and the multiple treatment group were 89.7% and 100% (P = 0.171). The incidence of adverse reactions in the single treatment group and the multiple treatment group was 13.8% and 14.3% (P > 0.999). The main manifestations were mild dysuria, frequent urination and other discomforts, all of which could be relieved. No severe bladder spasm or systemic photosensitivity reactions were observed. Conclusions: The combination of intravesical perfusion therapy and hematoporphyrin intravesical perfusion PDT for NMIBC has a significant effect. Increasing the frequency of intravesical PDT during the recurrence-free period can improve the RFS rate within 3 to 24 months, but there is no statistical difference in the PFS rate. Moreover, multiple hematoporphyrin intravesical perfusion PDT do not increase the incidence of adverse reactions. It is worthy of clinical promotion.