Background
Phase III RCT (National Wilms Tumor Study-3, NWTS-3). 1439 children with Wilms tumor enrolled 1979–1986. Four-arm factorial design examining: (1) doxorubicin necessity in stage II–III treatment; (2) RT dose reduction (10 Gy vs 20 Gy for stage III); (3) role of cyclophosphamide for stage IV. Landmark trial that refined RT dose and chemotherapy for Wilms tumor.
Interventions and follow up
Arm A: Stage II: vincristine + dactinomycin ± doxorubicin; no RT vs RT 20 Gy
Arm B: Stage III: vincristine + dactinomycin + doxorubicin ± cyclophosphamide; RT 10 Gy vs 20 Gy flank
Arm C: Stage IV: all received three-drug + whole lung RT ± cyclophosphamide
Primary endpoint: RFS, OS
mFollow up: 5.0 year
Arm B: Stage III: vincristine + dactinomycin + doxorubicin ± cyclophosphamide; RT 10 Gy vs 20 Gy flank
Arm C: Stage IV: all received three-drug + whole lung RT ± cyclophosphamide
Primary endpoint: RFS, OS
mFollow up: 5.0 year
Results
Stage III RT (10 vs 20 Gy): RFS equivalent — 10 Gy non-inferior (P=.34)
Stage II no RT + 2-drug chemo: RFS 87% — RT omission safe for stage II FH
Stage III doxorubicin benefit: Confirmed necessary for stage III
Cyclophosphamide stage IV: No benefit over standard three-drug regimen
Stage II no RT + 2-drug chemo: RFS 87% — RT omission safe for stage II FH
Stage III doxorubicin benefit: Confirmed necessary for stage III
Cyclophosphamide stage IV: No benefit over standard three-drug regimen
Adverse events
Main adverse events: RT reduction from 20 to 10 Gy: significantly reduced late musculoskeletal and growth effects. Doxorubicin: cardiotoxicity concern with cumulative dosing. Cyclophosphamide arm: hemorrhagic cystitis, secondary malignancy risk.
Conclusions
RT dose for stage III Wilms tumor was safely reduced from 20 to 10.8 Gy without loss of efficacy. Stage II favorable histology can be treated without RT. Doxorubicin remains essential for stage III. Cyclophosphamide adds no benefit for stage IV standard-risk disease.
Key Limitations
Key Limitations: Era-specific limitations (1979–1986 imaging). Surgical documentation of spillage and nodal status not fully standardized. Heterogeneous histology definitions across the enrollment period.
Clinical Context
NWTS-3 established the current RT dose of 10.8 Gy for stage III Wilms tumor (standard at all modern centers), replacing the older 20 Gy standard. This significant dose reduction reduced late scoliosis and musculoskeletal toxicity without compromising tumor control.
References
References: D'Angio GJ et al, Cancer 1989 (NWTS-3)