Wilms’ tumor or nephroblastoma is cancer of the kidneys that typically occurs in children, rarely in adults. Its common name is an eponym, referring to Dr. Max Wilms, the German surgeon (1867–1918) who first described this kind of tumor.
The first sign is normally a painless abdominal tumor that can be easily felt by the doctor. An Ultrasound, Computed Tomography, or MRI are done first. Once a kidney tumor is found, a surgical biopsy is done. A sample of tissue from the tumor is sent to a pathologist, who looks at it under a microscope to check for signs of cancer.
Stage I (43% of patients)
For stage I Wilms’ tumor, 1 or more of the following criteria must be met:
Tumor is limited to the kidney and is completely excised.
The surface of the renal capsule is intact.
The tumor is not ruptured or biopsied (open or needle) prior to removal.
No involvement of extrarenal or renal sinus lymph-vascular spaces
No residual tumor apparent beyond the margins of excision.
Metastasis of tumor to lymph nodes not identified.
Treatment: Nephrectomy +/- 18 weeks of chemotherapy depending on age of patient and weight of tumor. EG: less than 2 years old and less than 550g only requires Nephrectomy with observation
Outcome: 98% 4-year survival; 85% 4-year survival if anaplastic
Stage II (23% of patients)
For Stage II Wilms’ tumor, 1 or more of the following criteria must be met:
Tumor extends beyond the kidney but is completely excised.
No residual tumor apparent at or beyond the margins of excision.
Any of the following conditions may also exist:
Tumor involvement of the blood vessels of the renal sinus and/or outside the renal parenchyma.
The tumor has been biopsied prior to removal or there is local spillage of tumor during surgery, confined to the flank.
Extensive tumor involvement of renal sinus soft tissue.
Treatment: Nephrectomy + abdominal radiation + 24 weeks of chemotherapy
Outcome: 96% 4-year survival; 70% 4-year survival if anaplastic
Stage III (23% of patients)
For Stage III Wilms’ tumor, 1 or more of the following criteria must be met:
Unresectable primary tumor.
Lymph node metastasis.
Tumor is present at surgical margins.
Tumor spillage involving peritoneal surfaces either before or during surgery, or transected tumor thrombus.
Treatment: Abdominal radiation + 24 weeks of chemotherapy + nephrectomy after tumor shrinkage
Outcome: 95% 4-year survival; 56% 4-year survival if anaplastic
Stage IV (10% of patients)
Stage IV Wilms’ tumor is defined as the presence of hematogenous metastases (lung, liver, bone, or brain), or lymph node metastases outside the abdomenopelvic region.
Treatment: Nephrectomy + abdominal radiation + 24 weeks of chemotherapy + radiation of metastatic site as appropriate
Outcome: 90% 4-year survival; 17% 4-year survival if anaplastic
Stage V (5% of patients)
Stage V Wilms’ tumor is defined as bilateral renal involvement at the time of initial diagnosis. Note: For patients with bilateral involvement, an attempt should be made to stage each side according to the above criteria (stage I to III) on the basis of extent of disease prior to biopsy. The 4-year survival was 94% for those patients whose most advanced lesion was stage I or stage II; 76% for those whose most advanced lesion was stage III.
Treatment: Individualized therapy based on tumor burden
Stage I-IV Anaplasia
Children with stage I anaplastic tumors have an excellent prognosis (80-90% five-year survival). They can be managed with the same regimen given to stage I favorable histology patients.
Children with stage II through stage IV diffuse anaplasia, however, represent a higher-risk group. These tumors are more resistant to the chemotherapy traditionally used in children with Wilms’ tumor (favorable histology), and require more aggressive regimens.
CT Scan of 11 cm Wilms’ tumor of right kidney in 13-month-old patient.
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