Monday, January 26, 2009

Wilms tumor

MP presented a case of wilms tumor (no apostrophe now per Halperin).

 4yo girl with 2 weeks of an enlarging abdominal mass.  Plain film obtained and then CT scan obtained.  Heterogeneous mass ~10cm in size with a rim of enhancing tissues on the edge of the mass. (note that imaging utilizing ionizing radiation was used first in this case; normally ultrasound would be the first modality).

 Differential of a Abdominal Mass - Wilms, Neuroblastoma, Renal Cell, Clear Cell, ATRT (atypical teratoid rhabdoid tumor).  Rim of enhancing normal kidney is a big tip off.  Calcifications can be see in Neuroblastoma.

 W/U - U/S, urinalysis (hematuria, - but really to look for VMA, HVA from neuroblastoma), CT, CXR or CT chest, ?Biopsy only if bilateral or unresectable.  A biopsy automatically makes the patient stage III, and requires WART (whole abdomen RT)!

 Surgery is an initial question - IVC, renal vein invasion, intraperitoneal seeding, assesemtent of other kidney (consider partial nephrectomy).

 Stage I - limited to kidney

Stage II - surgically completely excised, with invasion beyond kidney, local flank spillage (now stage III)

Stage III - residual tumor in abdomen, +LN, peritoneal spillage (all biopsies are classified as stage III)

Stage IV - distant mets

Stage V - bilateral disease

Return to case.  Intraoperatively tumor was spilled into cavity.  LN negative.  Path demonstrated wilms tumor, margin negative, no anaplasia.

 Most common abdominal tumor - median age 3-4 years (unilateral).  4-8% are bilateral and tend to present earlier 2.5 years.

 11-13% have a syndrome

1. WAGR - 11p del, WT1, PAX6: aniridia. 

2. Beckwith-Widemann syndrome

3. Denys-Drash

 10% have anaplasia - poorer prognosis

 5y Overall survival usually on the order of 85-95%

 Treatment - US:  adjuvant treatments (NWTS) vs Europe - Neoadjuvant treatment (SIOP)

Advantages and disadvantages of both approaches are straightforward.  Definitive diagnosis with a higher risk of intrapertitoneal contaimination occurs with adjuvant treatment, while neoadjuvant approaches improves the chance of complete resection, with a chance of mistaken diagnosis (5% mistreated in SIOP trials).

 To cover the US randomized data:

 NWTS 1 (1969-1974)

1. RT necessary in group I : no RT needed if <2years.  No dose response beyond 20Gy

2. VCR vs AMD vs VCR + AMD in Group II, III : VCR+AMD better

3. preop VCR in group IV: not helpful

NWTS 2 (1974-1979)

1. group I - more VCR/AMD is not helpful

2. groups II-IV - Adriamycin adds to VCR/AMD (everyone gets RT)

also RT must start within 9 days of surgery

NWTS 3 (1979-1985)

1. stage I - shorter chemo? - shorter chemo OK

2. stage II - no rt vs 20Gy - no RT OK (also adriamycin not needed)

3. stage II - 10gy vs 20Gy - 10Gy OK (when adriamycin used)

4. stage IV - add Cyclophosphamide? - Cyclophosphamide didn’t help 

NWTS 4 (1985-1994)

no RT questions, all groups randomized to pulsed ChT (less toxic, equally efficacious)


question of further refined risk groups


Current RT Reccomendations:

Stage I - no RT

Stage II - no RT unless unfavorable histology (10.8 WART), or spillage (10.8 to flank)

Stage III - 10.8Gy to WART, 21.6Gy to Gross disease

Stage IV - 10.8 Gy to WART, 21.6Gy to Gross disease

Lung mets - 12Gy at 1.5Gy/day

In Europe, the series of SIOP trials have demonstrated that preop AMD+VCR x 4weeks - surgery - risk adapted adjuvant treatment is safe and effective.  Worth keeping in mind that AMD+VCR can be used neoadjuvantly if not initially resectable.   RT dose with high risk factors (stage III disease in NWTS system, stage IIN1 or III in SIOP system) is 15Gy.

Case Resolution.  Pt treated to Whole Abdomen to 10.8Gy.  Simmed with Fluoro to encompass whole abdomen from superiormost extent of diaphragmatic movement, to the bottom of the ischial rings.  Femoral head blocks placed.  Need to discuss future issues with infertility with parents/patient.


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