Advancements in treating rare pediatric kidney cancers - Children's National

Rare kidney cancers account for a quarter of pediatric kidney tumors and pose unique challenges for oncologists. In the past year, Jeffrey Dome, MD, PhD, and colleagues in the Children's Oncology Group published three landmark studies that are reshaping treatment for focal anaplastic Wilms tumor (FAWT), clear cell sarcoma of the kidney (CCSK), and malignant rhabdoid tumor (RT).

Focal anaplastic Wilms tumor

Recent findings show that children with stage I-II FAWT achieve 100% 4-year overall survival with vincristine/dactinomycin/doxorubicin chemotherapy (DD4A) plus flank radiation, while children with stage IV disease benefited from intensified regimens. These results confirm that therapy can be adjusted to disease stage, balancing survival with long-term side effects.

Clear cell sarcoma of the kidney

For CCSK, new evidence supports omitting radiation in stage I patients when lymph nodes are sampled, reducing treatment burden without sacrificing outcomes. Standard therapy consisting of vincristine/doxorubicin/cyclophosphamide/etoposide (Regimen I) plus flank radiation remains effective for stage II-III disease. For stage IV disease, addition of carboplatin to the standard regimen improves survival, although outcomes remain unsatisfactory, with the brain as the most common site of recurrence.

Malignant rhabdoid tumor

Rhabdoid tumors remain the most aggressive pediatric kidney cancer. Intensified chemotherapy has modestly improved survival, a result driven by patients with Stage I/II disease. Despite this improvement, outcomes for patients with rhabdoid tumor remain unsatisfactory and there is a need for novel therapeutic strategies, such as targeting SMARCB1 gene alterations, and immunotherapy approaches.

Why it matters

• Families: Some children can avoid radiation or prolonged chemotherapy, reducing long-term side effects.
• Clinicians: Clear guidance on when therapy can be reduced - or intensified.
• Researchers: New targets like SMARCB1 highlight the need for precision medicine in rhabdoid tumor, where intensification of chemotherapy has had only modest efficacy

Looking ahead

"These studies show real progress in tailoring treatment," said Dr. Dome. "But the next leap forward will come from biological therapies that directly target the drivers of these cancers."

With no active frontline trials currently open, the Children's Oncology Group is designing the next generation of studies to deliver more effective and less toxic therapies for these rare cancers.

Conclusion

From reducing radiation in CCSK to improving survival in FAWT and setting the stage for precision medicine in rhabdoid tumors, these advances are reshaping the outlook for children with rare kidney cancers. At Children's National, leaders like Dr. Dome are ensuring that even the rarest diagnoses are met with innovation and hope.

Read the full studies here: focal anaplastic Wilms tumor (FAWT), clear cell sarcoma of the kidney (CCSK), and malignant rhabdoid tumor (RT).