From 1971 to 2005, 174 cases of Wilms¡¯ tumors treated with an initial operation followed by adjuvant therapy were re-evaluated by the new histological classification. Histologically, all these materials showed no secondary changes associated with adjuvant therapy.
According to the new classification, Wilms¡¯ tumors were classified into four subtypes, including the mixed type (n = 112), epithelial type (n = 17), mesenchymal type (n = 15), and blastemal predominant type (n = 26). The 5 year overall survival rates were as follows; mixed type (90.1 % ), epithelial type (100 % ), mesenchymal type (93.3 % ), and blastemal predominant type (65.4 % ).
The patients with blastemal predominant tumors demonstrated a significantly worse prognosis compared with those of other subtypes. The treatment strategy of blastemal predominant category should be distinguished from the other favorable subtypes.