Active Surveillance Versus Adjuvant Intravesical Chemotherapy in Liquid Biopsy-Defined Low-Shedding Intermediate-Risk NMIBC

Inclusion Criteria:

1. Age ≥18 years.
2. Histologically confirmed urothelial carcinoma of the urinary bladder, including tumors with divergent differentiation, provided that the urothelial carcinoma component accounts for \>50% of the tumor
3. Non-muscle-invasive bladder cancer classified as intermediate-risk according to the 2021 European Association of Urology (EAU) NMIBC prognostic risk-group definition. Intermediate-risk disease is defined as NMIBC without concomitant carcinoma in situ that does not meet the criteria for the EAU low-, high-, or very-high-risk groups.
4. Complete transurethral resection of all visible bladder tumors performed within 6 weeks before randomization, with no macroscopically visible residual disease.
5. Negative multi-urinary liquid biopsy results after complete TURBT and before randomization.
6. Eastern Cooperative Oncology Group performance status of 0-2.
7. Adequate clinical condition to undergo protocol-specified intravesical therapy, cystoscopic surveillance, and study-related procedures.
8. Ability to understand the study requirements and provide written informed consent.

Exclusion Criteria:

1. EAU low-risk, high-risk, or very-high-risk NMIBC.
2. Any current or previous concomitant carcinoma in situ associated with the qualifying tumor episode.
3. Muscle-invasive bladder cancer, locally advanced urothelial carcinoma, lymph-node involvement, or metastatic urothelial carcinoma.

   Incomplete TURBT, macroscopically visible residual tumor, or inability to achieve complete endoscopic resection before randomization.
4. Urothelial carcinoma involving the prostatic stroma or prostatic ducts, or carcinoma in situ of the prostatic urethra.
5. Severe lower urinary tract dysfunction, bladder capacity considered insufficient for intravesical treatment, or another clinically significant urological condition that may interfere with treatment or outcome assessment.
6. Another active malignancy requiring systemic treatment or likely to interfere with the assessment of study endpoints, except adequately treated non-melanoma skin cancer, localized prostate cancer under surveillance, or another malignancy with a negligible risk of recurrence, as determined by the investigator.
7. Pregnant or breastfeeding women.
8. Any serious uncontrolled medical, psychiatric, or social condition that, in the investigator's judgment, would compromise participant safety, protocol adherence, or interpretation of study results.