The goal of this observational study is to evaluate the safety and efficacy of neoadjuvant therapy followed by bladder - preserving TMT in patients with MIBC. The main question it aims to answer is: Does this treatment model improve long - term outcomes, including survival, local control, distant metastasis, and bladder preservation rates? Participants who received neoadjuvant therapy and underwent TMT for bladder preservation will be observed.

Inclusion Criteria:

Histopathologically confirmed bladder cancer (T2-T4aN0-2M0, 8th edition AJCC staging).

Underwent bladder - sparing TMT following neoadjuvant therapy (ADC, immunotherapy, or chemotherapy).

Aged ≥18 years. Signed an informed consent form. Good general condition with ECOG performance status of 0-2. Adequate organ function for chemoradiotherapy: (1) Hematology: Absolute neutrophil count ≥1.5×10⁹/L, platelets ≥100×10⁹/L, hemoglobin ≥90 g/L. (2) Liver function: Total bilirubin ≤1.5×ULN, ALT and AST ≤2.5×ULN (≤5×ULN if hepatic metastasis is present). (3) Renal function: Creatinine clearance ≥30 mL/min (via Cockcroft-Gault formula).

Exclusion Criteria:

Distant metastasis (M1). Other malignancies (except cured basal cell carcinoma or cervical carcinoma in situ).

Severe cardiovascular disease (uncontrolled heart failure, unstable angina, myocardial infarction, etc.).

Severe hepatic/renal dysfunction intolerance to chemoradiotherapy. Mental illness/cognitive impairment unable to comply with the study. Allergy to chemoradiotherapy drugs. Pregnant or breastfeeding women. Previous pelvic radiotherapy.

Histopathologically confirmed bladder cancer (T2-T4aN0-2M0, 8th edition AJCC staging).

Underwent bladder - sparing TMT following neoadjuvant therapy (ADC, immunotherapy, or chemotherapy).

Aged ≥18 years. Signed an informed consent form. Good general condition with ECOG performance status of 0-2. Adequate organ function for chemoradiotherapy: (1) Hematology: Absolute neutrophil count ≥1.5×10⁹/L, platelets ≥100×10⁹/L, hemoglobin ≥90 g/L. (2) Liver function: Total bilirubin ≤1.5×ULN, ALT and AST ≤2.5×ULN (≤5×ULN if hepatic metastasis is present). (3) Renal function: Creatinine clearance ≥30 mL/min (via Cockcroft-Gault formula).