The UMBRELLA 2016-SIOP RTSG protocol emphasizes the specific challenges associated with bilateral Wilms tumor and strongly recommends discussion of these cases within a national multidisciplinary Wilms tumor board (MWTB).

A national MWTB dedicated to bilateral disease was established and rapidly expanded to include all complex cases. These monthly, web-based meetings require a minimum board and include participation from radiation oncologists, surgeons, pediatric oncologists, radiotherapists, and pathologists. Patients from all centers within the Société Française des Cancers de l’Enfant (SFCE) are reviewed.

From January 2018 to December 2023, the board held 251 case discussions concerning 171 patients. Reasons for referral included bilateral disease in 50.4%, syndromic patients in 5.8%, complex metastatic cases at diagnosis or relapse in 22.5%, thrombotic complications in 1.5%, and other complex presentations in 19.8% (e.g., tumor rupture, rare histology). The full multidisciplinary board was achieved in 78% of meetings. In two-thirds of cases, expert recommendations resulted in modification or adjustment of the initial proposal from the treating team, guiding individualized strategies rather than applying standard care alone. In particular, surgical type and timing were often specified. A survey indicated high levels of participant satisfaction.

This MWTB exemplifies successful national multidisciplinary collaboration and is aligned with current recommendations to enhance the quality of care for patients with complex presentations. Furthermore, the initiative surpasses the UMBRELLA objective, as it includes not only patients with stage V disease.