Study identifies diagnostic gap in an aggressive type of Wilms tumor - Children's National

A large Children's Oncology Group (COG) study found that hospitals generally diagnose and stage pediatric kidney tumors accurately, but identified an important gap in recognizing a rare, aggressive form of Wilms tumor.

Published in Pediatric Blood & Cancer, the study found that diffuse anaplastic Wilms tumor was missed by local institutions in about one-third of cases, highlighting the value of expert pathology review for difficult-to-diagnose tumors.

The big picture

Researchers analyzed 6,311 patients enrolled in the COG AREN03B2 Renal Tumor Biology and Classification Study from 2006 to 2019. They compared assessments by local pathologists, radiologists and surgeons with real-time reviews by central experts.

These evaluations determine a tumor's diagnosis, stage and risk classification, which helped assign patients to appropriate clinical trials for treatment, while also helping care teams select the most appropriate treatment outside research studies.

What the study found

Overall, local institutions and central experts agreed on the pathological diagnosis in 91.1% of cases, the assessment of lung nodules on CT scans in 96.1% and surgical staging in 90%. When researchers considered all risk factors together, local institutions assigned the same treatment-risk category as central reviewers 87% of the time.

The largest discrepancy involved diffuse anaplastic Wilms tumor, an aggressive and treatment-resistant subtype that comprises about 5 to 10% of Wilms tumors. Local institutions correctly identified 181 of 269 cases, or 67%. Because more intensive treatment is needed to achieve successful outcomes for anaplastic Wilms tumor, an accurate identification of this subtype is especially important.

"Accurately identifying anaplastic Wilms tumor is critical because it influences treatment, and ultimately, patient outcome," said Jeffrey Dome, MD, PhD, co-senior author of the study and senior vice president of the Cancer and Blood Disorders Center at Children's National. "While our findings show that pediatric kidney tumors are diagnosed and staged accurately in most cases, they also demonstrate the value of expert pathology review when evaluating rare, aggressive tumor features that can be difficult to recognize."

Why it matters

The findings show that COG institutions assess most pediatric kidney tumors with a high degree of accuracy. They also demonstrate where specialized expertise can make a difference.

For children with diffuse anaplastic Wilms tumor, an accurate diagnosis is particularly important because tumor classification helps determine treatment intensity. Missing anaplastic features could result in a child receiving less intensive treatment than their disease requires.

What's next

The researchers say expert pathology consultation remains important for institutions with limited experience evaluating pediatric kidney tumors. Current research seeks to identify anaplastic histology by detecting molecular changes in circulating tumor DNA. There are also initiatives to harness artificial intelligence to identify anaplastic Wilms tumor based on the appearance of histology slides.

Read the full study, Concordance Between Institutional and Central Pathology, Surgery, and Radiology Reviews on the Children's Oncology Group AREN03B2 Renal Tumor Biology and Classification Study, in Pediatric Blood & Cancer.