Wilms' tumor

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Wilms' tumor
File:Wilms tumor.jpg
Cut section showing two halves of a nephroblastoma specimen. Note the prominent septa subdividing the sectioned surface and the protrusion of tumor into the renal pelvis, resembling botryoid rhabdomyosarcoma.
Classification and external resources
Specialty Oncology
ICD-10 C64
ICD-9-CM 189.0
ICD-O M8960/3
OMIM 194070 607102
DiseasesDB 8896
MedlinePlus 001575
eMedicine med/3093 ped/2440
Patient UK Wilms' tumor
MeSH D009396
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]
CT Scan of 11 cm Wilms tumor of right kidney in 13-month-old patient.

Wilms (/vɪlmz/) tumor, Wilms' tumor, or nephroblastoma is a cancer of the kidneys that typically occurs in children, rarely in adults.[1] It is named after Dr. Max Wilms, the German surgeon (1867–1918) who first described it.[2]

Approximately 500 cases are diagnosed in the U.S. annually. The majority (75%) occur in otherwise normal children; a minority (25%) are associated with other developmental abnormalities. It is highly responsive to treatment, with about 90% of patients surviving at least five years.

Signs and symptoms

Typical signs and symptoms of Wilms' tumor include the following:

  • an abnormally large abdomen
  • abdominal pain
  • fever
  • nausea and vomiting
  • blood in the urine (in about 20% of cases)
  • high blood pressure in some cases (especially if synchronous or metachronous bilateral kidney involvement)

Pathogenesis

File:Wilms tumour - low mag.jpg
Micrograph showing the characteristic triphasic pattern consisting of tubules, solid sheets of small round cells, and stroma. H&E stain.
File:Wilms tumour - very high mag.jpg
High magnification micrograph showing the epithelial component (tubules). H&E stain.

Most nephroblastomas are on one side of the body only and are found on both sides in less than 5% of cases, although patients with Denys-Drash syndrome mostly have bilateral or multiple tumors.[3] They tend to be encapsulated and vascularized tumors that do not cross the midline of the abdomen. In cases of metastasis it is usually to the lung. A rupture of Wilms tumor puts the patient at risk of bleeding and peritoneal dissemination of the tumor. In such cases, surgical intervention by a surgeon who is experienced in the removal of such a fragile tumor is imperative.

Pathologically, a triphasic nephroblastoma comprises three elements:

Wilms tumor is a malignant tumor containing metanephric blastema, stromal and epithelial derivatives. Characteristic is the presence of abortive tubules and glomeruli surrounded by a spindled cell stroma. The stroma may include striated muscle, cartilage, bone, fat tissue, fibrous tissue. Dysfunction is caused when the tumor compresses the normal kidney parenchyma.

The mesenchymal component may include cells showing rhabdomyoid differentiation or malignancy (rhabdomyosarcomatous Wilms).

Wilms tumors may be separated into 2 prognostic groups based on pathologic characteristics:

  • Favorable - Contains well developed components mentioned above
  • Anaplastic - Contains diffuse anaplasia (poorly developed cells)

Molecular biology

Mutations of the WT1 gene on chromosome 11p13 are observed in approximately 20% of Wilms tumors.[4][5] At least half of the Wilms tumors with mutations in WT1 also carry mutations in CTNNB1, the gene encoding the proto-oncogene beta-catenin.[6]

A gene on the X chromosome, WTX, is inactivated in up to 30% of Wilms tumor cases, according to research published in 2007.[7]

Most cases do not have mutations in any of these genes.[8]

Diagnosis

The first sign is normally a painless abdominal tumor that can be easily felt by the doctor. An ultrasound scan, computed tomography scan, or MRI scan is done first. A tumor biopsy is not typically performed due to the risk of creating fragments of cancer tissue and seeding the abdomen with malignant cells.

Staging

Staging is a standard way to describe the extent of spread of Wilms tumors,[9] and to determine prognosis and treatments. Staging is based on anatomical findings and tumor cells pathology.[10][11]

Definitions of stages

Stage I (43% of patients)

Stage I Wilms tumor, all 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.

Stage II (23% of patients)

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.

Stage III (20% of patients)

Stage III Wilms tumor, 1 or more of the following criteria must be met:

  • Inoperable 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.

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.

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.

Prognosis

The overall 5-year survival is estimated to be approximately 90%,[12][13] but for individuals the prognosis is highly dependent on individual staging and treatment. Early removal tends to promote positive outcomes.

Tumor-specific loss-of-heterozygosity (LOH) for chromosomes 1p and 16q identifies a subset of Wilms tumor patients who have a significantly increased risk of relapse and death. LOH for these chromosomal regions can now be used as an independent prognostic factor together with disease stage to target intensity of treatment to risk of treatment failure.[14][15] Genome-wide copy number and LOH status can be assessed with virtual karyotyping of tumor cells (fresh or paraffin-embedded).

Statistics may sometimes show more favorable outcomes for more aggressive stages than for less aggressive stages, which may be caused by more aggressive treatment and/or random variability in the study groups. Also, a stage V tumor is not necessarily worse than a stage IV tumor.

Stage[16] Histopathology[16] 4 Year relapse-free survival (RFS) or event-free survival (EFS)[16] 4 Year overall survival (OS)[16] Treatment[16]
Stage I [16] Favorable histology in children younger than 24 months or tumor weight less than 550g 85% 98% Surgery only (should be done only within the context of a clinical trial)
Favorable histology in children older than 24 months or tumor weight more than 550g 94% RFS 98% Nephrectomy + lymph node sampling followed by regimen EE-4A
Diffuse anaplastic 68% EFS 80% Nephrectomy + lymph node sampling followed by regimen EE-4A and radiotherapy
Stage II[16] Favorable histology 86% RFS 98% Nephrectomy + lymph node sampling followed by regimen EE-4A
Focal anaplastic 80% EFS 80% Nephrectomy + lymph node sampling followed by abdominal radiotherapy and regimen DD-4A
Diffuse anaplastic 83% EFS 82% Nephrectomy + lymph node sampling followed by abdominal radiotherapy and regimen I
Stage III[16] Favorable histology 87% RFS 94% Nephrectomy + lymph node sampling followed by abdominal radiotherapy and regimen DD-4A
Focal anaplastic 88% RFS 100% (8 people in study) Nephrectomy + lymph node sampling followed by abdominal radiotherapy and regimen DD-4A
Focal anaplastic (preoperative treatment) 71% RFS 71% Preoperative treatment with regimen DD-4A followed by nephrectomy + lymph node sampling and abdominal radiotherapy
Diffuse anaplastic 46% EFS 53% Preoperative treatment with regimen I followed by nephrectomy + lymph node sampling and abdominal radiotherapy
Diffuse anaplastic 65% EFS 67% Immediate nephrectomy + lymph node sampling followed by abdominal radiotherapy and regimen I
Stage IV[16] Favorable histology 76% RFS 86% Nephrectomy + lymph node sampling, followed by abdominal radiotherapy, bilateral pulmonary radiotherapy, and regimen DD-4A
Focal anaplastic 61% EFS 72% Nephrectomy + lymph node sampling, followed by abdominal radiotherapy, bilateral pulmonary radiotherapy, and regimen DD-4A
Diffuse anaplastic 33% EFS 33% Immediate nephrectomy + lymph node sampling followed by abdominalradiotherapy, whole-lung radiotherapy, and regimen I
Diffuse anaplastic (preoperative treatment) 31% EFS 44% Preoperative treatment with regimen I followed by nephrectomy + lymph node sampling followed by abdominalradiotherapy, whole-lung radiotherapy
Stage V[16] Overall 61% EFS 80%
Favorable histology 65% 87% Bilateral renal biopsies and staging of each kidney followed by preoperative treatment with regimen EE-4A (if disease in both kidneys ≤ stage II) or regimen DD-4A (if disease in both kidneys > stage II), followed by second-look surgery and possibly more chemotherapy and/or radiotherapy
Focal anaplastic 76% 88% Bilateral renal biopsies and staging of each kidney followed by preoperative treatment with regimen I, followed by second-look surgery and possibly more chemotherapy and/or radiotherapy
Diffuse anaplastic 25% 42% Bilateral renal biopsies and staging of each kidney followed by preoperative treatment with regimen I, followed by second-look surgery and possibly more chemotherapy and/or radiotherapy

Epidemiology

People of African descent[where?] have the highest rates of Wilms' tumor. Most instances of cancer occur among children between 3 to 3.5 years old.[citation needed] A genetic predisposition to Wilms' Tumor in individuals with aniridia has been established, due to deletions in the p13 band on chromosome 11.[17]

History

Dr. Sidney Farber, founder of Dana-Farber Cancer Institute, and his colleagues achieved the first remissions in Wilms tumor in the 1950s. By employing the antibiotic actinomycin D in addition to surgery and radiation therapy, they boosted cure rates from 40 to 85 percent.

See also

References

  1. EBSCO database verified by URAC; accessed from Mount Sinai Hospital, New York
  2. WhoNamedIt.com: Max Wilms
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  16. 16.0 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 Unless otherwise specified in boxes, then reference is: Treatment of Wilms Tumor at National Cancer Institute. Last Modified: 03/29/2012
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External links