Heterogeneity of disease classified as stage III in Wilms tumor: a report from the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP).

Purpose: We analyzed whether the prognosis can differ among Wilms tumors (WT) labeled as Stage III according to currently adopted classification systems.

Methods And Materials: Patients with nonanaplastic Stage III WT consecutively registered in two Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) trials (CNR-92, TW-2003) were the subjects in the present analysis. The steady mainstay of therapy was primary nephrectomy, followed by three-drug chemotherapy with vincristine, dactinomycin, doxorubicin, and abdominal radiotherapy (RT).

Results: Ninety-nine WT patients met the criteria for classification as Stage III according to a revised version of the National Wilms Tumor Study-3 staging system (51 patients in CNR-92, 48 patients in TW-2003). Regional lymph nodes (LN) were not biopsied in 16 patients. After a median follow-up of 66 months, the 4-year disease-free survival (DFS) and overall survival (OS) rates were 85% ± 4% and 92% ± 3%, respectively, for the whole group. For 38 children with positive LN, the 4-year DFS rate was 73% ± 7%, as opposed to 98% ± 2% for the 45 children with Stage III WT according to the other criteria but with negative biopsied LN (p = 0.001). The subgroup with the worst prognosis consisted of children more than 2 years old with positive LN (DFS 67% ± 8%). A delay between surgery and RT > 30 days had an adverse impact on the abdominal tumor relapse rate.

Conclusions: This study provides further evidence that Stage III tumors with LN metastases might be distinguished from WTs meeting the other criteria for classification as Stage III. The worse outcome of the former may warrant a prospective study on the effects of intensified therapy. A subclassification of Stage III tumors is discussed.