For patients with high risk and very high risk relapsed WTs, chemotherapy (alternating courses of cyclophosphamide/etoposide and carboplatin/etoposide), surgery, and/or radiation therapy and hematopoietic stem cell transplantation are recommended.
1 For standard-risk relapsed WTs, surgery is given when feasible radiation therapy and chemotherapy (alternating courses of vincristine/doxorubicin/cyclophosphamide and etoposide/cyclophosphamide) are given. The COG guideline has categorized the patients with recurrent WT into three risk groups: standard risk, high risk and very high risk. Outcome has recently improved to 60% in patients with relapse. Historically, the mortality rate of patients with recurrent favorable histology, WT ranges from 25% to 40%.
19 The leading locations of relapse are the lung, abdomen/flank and liver. The recurrence rate in patients with familial hypercholesterolemia WT is about 15% and patients with anaplastic histology is about 50%. 8 Nephron-sparing surgery is used for non-syndromic unilateral WTs under following conditions such as with small tumor volume (<300 mL) and the expectation of a substantial remnant kidney function in patients who never had lymph node involvement. Lymph node sampling is important for staging, and sampling seven locoregional lymph nodes is necessary for accurate staging. The SIOP recommends radical tumor nephrectomy performed after preoperative chemotherapy. 12 Resection of the primary renal tumor should be considered even if in a stage IV disease (usually pulmonary metastases) renal-sparing surgery is not recommended by COG guideline, except when children having a solitary kidney, with predisposition to bilateral tumors, horseshoe kidney or in infants with Denys-Drash or Frasier syndrome (to delay the need for dialysis). 7 En bloc resection can be done to avoid tumor spill. 7 Radical nephrectomy and lymph node sampling are done through a transabdominal incision. For resectable tumors, preoperative biopsy or intraoperative biopsy is also not performed. The COG recommends primary surgery before chemotherapy. The purpose of this review is to present the similarities and differences of diagnosis and treatment strategies of WT used worldwide mainly based on COG and SIOP guidelines. Large-scale clinical trials have found that the two treatment strategies have their own advantages and disadvantages. The major difference exists in the two guidelines is the timing of surgery: SIOP recommends using preoperative chemotherapy and NWTSG/COG prefers using primary surgery before any adjuvant treatments. The NWTSG/COG 7 and SIOP 8 guidelines are the two major guidelines used for the current management of WT worldwide. Mutidisciplinary collaborative groups are involved in the diagnosis and treatment of WT. The current survival in patients with WT is high (90%). 5 Studies on the etiology of these syndromes have shown a link between the occurrence of WT and disorders of chromosome 11 genes, such as WT1 and WT2. 4 Children with WAGR syndrome, Beckwith-Wiedemann syndrome, Denys-Drash syndrome, and Edwards or Perlman syndromes, may be more likely to have WT. 3Īlthough WT can be inherited at autosomal dominant mode, most patients are sporadic. In most populations, no gender difference has been found in cases with WT however, females are more likely to have WT than males (combined M:F=1:4) in some Asian countries. US National Wilms Tumor Study revealed that the median onset age is 38 months, and girls had diseased onset 6 months older than boys. The incidence is much lower (3–4 per 10 000 children) in Asian countries. 1 2 The incidence of WT is about 1 per 10 000 children in Europe and North America. Wilms tumor (WT nephroblastoma) is the most common malignant renal tumor in children, accounting for about 85% of pediatric renal tumors.
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