Bladder cancer is a common malignant tumor, with non-muscle-invasive bladder cancer (NMIBC) accounting for approximately 75% of bladder cancer patients. Of these NMIBC patients, 50-70% have tumor recurrence and 15% have tumor progression, thus most patients may require prolonged cystoscopy and therapeutic intervention. According to the EAU guideline, intravesical therapy of BCG is the standard treatment of high-risk NMIBC patients, as it reduces the risk of tumor recurrence and progression. There has long been controversial about the dosage and period of BCG treatment and long-term BCG treatment may cause frequent adverse effects such as hematuria and urinary frequency，because of which many patients failed to complete the whole period of treatment. Also, some patients showed no response to BCG and underwent tumor progression after BCG treatment. Based on the above considerations, trying to improve the treatment for NMBIC patients is important. Recent study showed that the rate of BCG response and tumor recurrence after BCG treatment may be related to PD-L1 expression, indicating that the therapeutic effect of BCG treatment combined with ICIs remains to be explored. Besides, since the molecular subtype of NMIBC has not been well standardized, and molecular subtype may guide treatment options, the correlation between NMIBC molecular subtypes and immunotherapy still remains to be verified by further studies. Since circulating tumour DNA (ctDNA) holding promise as a biomarker for molecular residual disease and relapse, next generation sequencing (NGS) of ctDNA may also benefit treatment options. This trial investigates the safety and efficacy of intravesical therapy of BCG combined with Tislelizumab for BCG-untreated patients with high-risk NMIBC as well as the relationship between the efficacy and tumor subtypes.
For patients with high-risk non-muscle-invasive bladder cancer (NMIBC), intravesical therapy of BCG is the standard treatment proved to reduce the risk of recurrence and progression. However, there are patients failed to complete the whole treatment due to the long period and some patients showed no response to BCG or suffered tumor progression after BCG treatment. The aim of this study is to examine the efficacy and safety of intravesical therapy of BCG combined with PD-1 monoclonal antibody as the treatment of high-risk NMIBC patients without BCG treatment. At the same time, transcriptome sequencing is used to analyze the correlation between the efficacy of the treatment and the level of immune cell infiltration and tumor molecular subtypes.