Tetra-modality Bladder Preservation Strategies in Muscle-invasive Bladder Cancer: TURBT+ Chemo/Immunotherapy+ Radiation Therapy+ Maintenance Immunotherapy vs. W&W

Muscle-invasive bladder cancer (MIBC) is an aggressive form of bladder cancer, with a 5-year survival rate of about 40%.

The standard treatment for MIBC is induction platinum-based chemotherapy followed by radical cystectomy. Recently bladder preservation strategies have emerged as an alternative to radical cystectomy, particularly useful for patients who are unfit for surgery or would rather opt for non-surgical approaches. Knowing the high risks related to surgery and its significant complications, the investigators propose to implement 2 tetra-modalities treatment strategies to increase the chance of preserving the bladder and decrease the need of salvage cystectomy.

The purpose of this study is to assess the efficacy and safety of 2 bladder-preservation treatments plans called tetra-modalities:

First plan:

* maximium TURBT * chemo-immunotherapy as induction phase (Avelumab added to chemotherapy) * radiation therapy * maintenance phase with Avelumab

Second plan:

* Maximum TURBT * chemo-immunotherapy as induction phase (Avelumab added to chemotherapy) * radiation therapy * Watch and wait

Both tetra-modalities duration will last maximum of 2 years from patient inclusion.

These treatment plans are based on the synergistic action between immunotherapy, chemotherapy, and radiotherapy. The use of Avelumab in the maintenance group is supported by its proven success in treating advanced cancer and various studies looking at immunotherapy as a way to avoid or delay bladder removal.