Wilms Tumor: Audio Chapter
With Dr. Peter Ehrlich · hosted by Dr. Abdul Raoof Lamoshi & Dr. Todd Ponsky · StayCurrentMD
Cued at 31:19 · stops at 32:04 · press play
Educational content from recorded physician discussions — not medical advice. Talk to your (or your child's) care team about your situation.
Podcast
Wilms Tumor: Audio Chapter
64 min · Published Jun 2017
Podcast
Topics in 10: Wilms Tumor
12 min · Published Aug 2019
Video
Wilms Tumor
Published May 2020
Video
Wilms Tumor Protocol Violations: Practice Gap discussion at Update Course 2018
9 min · Published Aug 2018
Video
Wilms Tumor Protocol Violations: 2018 Pediatric Surgery Practice Gap #3
Dr. Todd Ponsky · Published Jun 2019
Video
Long-Term Follow-Up of Surgical Outcomes for Patients With Wilms Tumor and Neuroblastoma
1 min · Published Feb 2026
Only a few other public items share this expert — go deeper there →
Video
Pediatric Surgical Oncology Research Collaborative (PSORC): Studying Rare Pediatric Tumors
56 s · Published May 2026
Video
Update Course Rewind 2025: Hirschsprung + ARM: Rare but Real
1 min · Published May 2026
Video
Update Course Rewind 2025: Hirschsprung + ARM: Rare but Real
1 min · Published May 2026
Video
Pooling Patients to Study Rare Pediatric Tumors: An Introduction to PSORC
56 s · Published May 2026
Video
The fetal frontier: A review of current and emerging fetal therapies for genetic diseases
44 s · Published May 2026
Video
Indocyanine green assists with sentinel lymph node mapping in pediatric and adolescent patients
1 min · Published May 2026
What the experts said
The 'claw sign' on CT—normal kidney displaced into a horseshoe pattern around a mass—is a classic feature of Wilms tumor.
Wilms tumor tends to push structures out of the way rather than growing into them, whereas neuroblastoma grows around structures like blood vessels.
In North America, the preferred approach for resectable Wilms tumor is primary nephrectomy (total nephrectomy and ureterectomy with lymph node sampling).
Preoperative chemotherapy is recommended if tumor extends into the IVC beyond the infrahepatic vena cava, if tumor is so large it compromises respiratory status, if major liver or bowel resection would be required, if only one functioning kidney exists, or if bilateral tumors are present.
If a tumor requires major liver or bowel resection, biopsy and preoperative chemotherapy are preferred because complication rates are higher when these organs are resected at the same time as the kidney, and most tumors will respond to chemotherapy.
Biopsy with residual gross tumor has always been treated as stage 3 abdominal disease, requiring three-drug chemotherapy plus flank radiation.
Evidence suggests higher risk of tumor rupture when tumors reach 13-15 centimeters or larger, which may warrant consideration of preoperative chemotherapy.
For biopsy, open biopsy provides large tissue sections; large-core needle biopsy (10-20 cores) has proven accurate in several series. Fine needle aspiration or single-pass true-cut biopsy cannot diagnose anaplasia and should not be used.
COG stage 1 is tumor limited to kidney, completely resected, no capsular invasion, no rupture or biopsy, vessels of renal sinus not involved, negative margins, and negative regional lymph nodes.
COG stage 2 is complete resection with negative margins but tumor extends beyond kidney through capsular penetration, renal sinus invasion, or blood vessel involvement within the nephrectomy specimen outside the primary kidney.
COG stage 3 includes: biopsy with gross residual tumor, positive lymph nodes, peritoneal surface penetration with implants, positive margins, microscopic residual from intraoperative spill, incomplete resection, piecemeal removal, or renal vein division with tumor present.
COG stage 4 is hematogenous metastasis to lung, liver (most common), bone, or brain. Stage 5 is bilateral renal tumor involvement.
Stage 1-2 abdominal disease without lung metastases receives two-drug chemotherapy (vincristine and dactinomycin) for shorter duration without abdominal radiation, significantly reducing late effects including renal failure, second malignancies, and cardiovascular disease.
If a patient has a lung lesion but stage 1-2 abdominal disease after primary nephrectomy with negative lymph nodes, the child avoids abdominal radiation (though still receives chemotherapy for the lung lesion).
Fifteen percent of girls who receive pulmonary radiation for Wilms tumor develop breast cancer, a significant late effect.
Recent COG data shows approximately 40% of patients with pulmonary metastases who have complete response at 6 weeks can avoid pulmonary radiation without affecting event-free or overall survival, with 80-85% not relapsing.
For a single lung lesion remaining at 6 weeks that did not respond to chemotherapy, thoracoscopic biopsy is reasonable because 50-60% of such lesions may not be cancer (could be scar), and if benign, the patient would not need pulmonary radiation.
SIOP protocols use preoperative chemotherapy for all patients at higher doses than COG, with evaluation at 4 and 8 weeks, then resection followed by post-chemotherapy pathology-based risk stratification (low, intermediate, high risk).
In SIOP protocols, predominantly blastema component after preoperative chemotherapy is a negative prognostic factor, but blastema percentage does not correlate with outcome in COG primary nephrectomy patients.
The main factor predicting outcome in stage 3 disease is whether lymph nodes are positive, along with genetic changes including loss of heterozygosity and 1Q gain.
Outcomes for stage 1 and stage 2 patients are basically identical between COG and SIOP treatment approaches.
Some Wilms tumor patients present with low hemoglobin because the tumor ruptures internally and bleeds.
Acquired von Willebrand disease occurs in Wilms tumor patients; in most cases it is meaningless, but a few case series report significant intraoperative bleeding until tumor removal.
Right-sided tumors can cause complications including adrenal vein injury, duodenal injury (due to proximity), superior mesenteric artery injury, and IVC injury due to anatomic distortion.
Wilms tumors can cause intense inflammatory reaction making them adherent to diaphragm or liver; taking a rim of diaphragm or liver capsule to avoid tumor violation does not upstage the tumor if the tumor itself is not divided.
A small subset of very young patients (<24 months) with stage 1 favorable histology tumors <550g can be treated with surgery alone without chemotherapy, with >95% overall survival. Those who relapse (about 10%) have 100% salvage with chemotherapy.
IVC tumor extension is not a negative prognostic factor if the tumor is completely resected.
Major complication rate for primary surgery with tumor extending beyond infrahepatic IVC is 26-30%, including mortality, increased transfusions, and ICU stay, supporting preoperative chemotherapy for these cases.
Favorable histology Wilms tumor has three components: blastema, stroma, and epithelial (triphasic tumor). Tumors with only two components are also considered favorable histology.
Patients with loss of heterozygosity of both 1p and 16q (5-7% of patients) have significantly worse outcomes regardless of stage. Stage 1-2 patients with LOH have about 10% lower overall survival; stage 3-4 patients have 18% lower survival.
Patients with both 1p and 16q loss of heterozygosity receive augmented therapy: doxorubicin is added for stage 1-2 disease, and five-drug regimen M is used for stage 3-4 disease.
Unfavorable histology is classified as focal anaplasia or diffuse anaplasia based on number of high-power fields showing anaplasia, with different treatments for each.
Renal cell carcinoma in children has no good therapy, particularly for metastatic disease.
Clear cell sarcoma of the kidney has reasonable treatment outcomes, particularly for low stages. Rhabdoid tumors have poor outcomes except for stage 1; most present at stage 3-4 with terrible outcomes.
Bilateral Wilms tumors occur in 8-10% of all children with Wilms tumor.
The strategy for bilateral Wilms tumor is preoperative chemotherapy to shrink tumors enough to allow partial nephrectomy of at least one kidney (ideally both) to avoid dialysis.
Event-free survival for bilateral Wilms tumor on NWTS-5 was 61% compared to 88% for unilateral tumors; overall survival was 80% vs. 95%.
Maximum tumor response to chemotherapy in most children with Wilms tumor occurs by 12 weeks, and early response at 6 weeks predicts late response.
In children presenting under 36 months with bilateral renal tumors, it is almost universally Wilms tumor. In a recent COG study of 250 enrolled patients, only one turned out to have rhabdoid tumor.
Biopsy is recommended for bilateral tumors in older patients (8-10 years) or those with syndromes like von Hippel-Lindau where renal cell carcinoma is more likely.
If biopsying bilateral tumors, both kidneys should be biopsied because there is discordant pathology in up to 20% of patients.