Investigating the Efficacy and Safety of Neoadjuvant Intravesical Instillation of Mitomycin C Combined with En-bloc Surgery in Treating High-risk Non-muscle-invasive Bladder Cancer (NMIBC) Patients
The goal of this clinical trial is to learn if neoadjuvant intravesical instillation of mitomycin C combined with en-bloc surgery works to treat high-risk non-muscle-invasive bladder cancer (NMIBC) patients. It will also learn about the safety of neoadjuvant intravesical instillation of mitomycin C. The main questions it aims to answer are: Does neoadjuvant intravesical instillation of mitomycin C heighten the 1-year recurrence-free survival (RFS) rate for high-risk non-muscle-invasive bladder cancer (NMIBC) patients? What medical problems do participants have when taking neoadjuvant intravesical instillation of mitomycin C? Researchers will compare neoadjuvant intravesical instillation of mitomycin C to a placebo (normal saline) to see if neoadjuvant intravesical instillation of mitomycin C works to treat high-risk NMIBC. Participants will: Take neoadjuvant intravesical instillation of mitomycin C or a placebo twice，1 day and 4 hours before en-bloc surgery Visit the clinic once every 8 weeks for checkups and tests Keep track of the recurrence and progression of the tumor.
• Voluntarily sign an informed consent form, understand the study and are willing and able to follow and complete all trial procedures
• Gender is not limited, age between 18 to 75 years old (inclusive of boundary values)
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
• Previously confirmed non-muscle-invasive bladder cancer by imaging and pathology
• In accordance with the EAU Guidelines (2024 edition) high-risk NMIBC patient danger grouping. All T1 HG/G3 and CIS patients except for the extremely high-risk group; Ta LG/G2 or T1G1, non-CIS with three risk factors; Ta HG/G3 or T1 LG, non-CIS with at least two risk factors; T1G2 non-CIS with at least one risk factor. (Risk factors: age \> 70 years; multiple papillary tumors; tumor diameter \> 3cm)
• Participants are willing to provide the last cystoscopy biopsy specimen or specimens from the previous recurrence surgery (including paraffin blocks, paraffin-embedded sections, etc.)
• The interval between previous anti-tumor treatments (chemotherapy, radiotherapy, immunotherapy) and the first administration of this trial is ≥6 weeks
• Suitable organ function and hematopoietic function: Neutrophil count (NEUT ≥ 1.5 × 10\^9/L; White blood cell count (WBC) ≥ 3.0 × 10\^9/L; Platelet count ≥ 100 × 10\^9/L; Hemoglobin ≥ 90g/L; Serum creatinine ≤ 1.5 times the upper limit of normal (ULN); AST and ALT ≤ 2.5 times ULN; Serum total bilirubin ≤ 1.5 times ULN; Activated partial thromboplastin time (APTT) ≤ 1.5 times ULN (except for patients on anticoagulant therapy)
• Male participants must agree to use effective contraceptive measures during the treatment period and for at least 180 days after the last treatment, and must not donate sperm during this period; women of childbearing age must have a negative blood pregnancy test within 72 hours before the first new adjuvant instillation, and must agree to use effective contraceptive measures during the treatment period and for at least 180 days after en-bloc treatment