In part because of their rarity, the development of guidelines for pediatric cancers by the National Comprehensive Cancer Network (NCCN) has lagged behind the creation of those for adult cancers. However, the organization is catching up, with its recently published guidelines for pediatric blood cancers, including acute lymphoblastic leukemia, Hodgkin lymphoma, and aggressive mature B-cell lymphoma.1-3 In addition, the NCCN recently issued the first guidelines for Wilms tumor (nephroblastoma), a rare solid tumor representing approximately 5% of childhood cancers and more than 90% of renal cancers in patients younger than 20 years.4
The panel of 25 experts from numerous US cancer centers synthesized the evidence on screening, diagnosis, risk stratification, and treatment, largely based on a number of trials dating back to 1969 led by the National Wilms Tumor Study Group, which later became the Children’s Oncology Group (COG). While making impressive inroads in treating Wilms tumors — 5-year survival is now greater than 90% — these trials have created a markedly complex treatment landscape.
“It is clear that this one entity of Wilms tumor represents a significant biologic spectrum for which therapy to cure the child can be only removing the tumor and the kidney or can require very intensive [therapies] with significant risk of long-term effects,” said Elizabeth Mullen, MD, program leader for renal tumors at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and a member of the NCCN panel. “That is in part what makes treating this disease daunting and is exactly why it’s helpful to have these guidelines.”
Notably, the NCCN guidelines only pertain to tumors with favorable histology and do not include diffuse anaplastic tumors, which represent only 5% of Wilms tumors and for which there is less clarity around standard therapy, Dr Mullen said.
Starting with screening, the guidelines recommend that children with known predisposing conditions undergo physical examination and renal ultrasound every 3 months until at least 8 years of age. Up to 20% of Wilms tumor cases occur in children with predisposing conditions, including the growth disorder Beckwith-Wiedemann syndrome; Denys-Drash syndrome, which is characterized by male pseudohermaphroditism and glomerulopathy; and WAGR syndrome, which predisposes individuals to Wilms tumor, aniridia, genitourinary problems, and developmental delays.
This screening approach “[has] been pretty successful at detecting tumors early on, which makes it more likely [that] . . . you’ll be able to successfully remove the tumor from their kidney without having to take the kidney out,” noted Frank M. Balis, MD, professor of pediatrics and Louis and Amelia Canuso family endowed chair for clinical research in Oncology at the Children’s Hospital of Philadelphia and the University of Pennsylvania’s Abramson Cancer Center, who chairs the NCCN guidelines panel for Wilms Tumor.