Outcome in stage IV Wilms tumor treated according to the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) trials

10031 Background: Children with metastases at diagnosis for Wilms tumor (WT) still display a worse prognosis compared to localized disease. Methods: We analyzed survival results in patients with stage IV WT enrolled in the AIEOP CNR92 and TW2003 clinical trials (3/1992–3/2008). Treatment strategy across these trials evolved in terms of sparing whole lung radiotherapy (RT) in case of complete disappearance of lung metastases after primary chemotherapy and a doxorubicin cumulative dose reduction from 360 mg/m2 to 240 mg/m2 in TW2003. Results: Of 553 in-study patients aged less than 18 years, 68 (12%) were classified as stage IV (38 patients in CNR92, 30 in TW2003; median age 58 months). Children displaying millimetric nodules visible only on computed tomography scan were excluded. Initial treatment consisted of 6-week 3-drug (vincristine, dactinomycin, doxorubicin) phase in 60 cases, while 8 had up-front nephrectomy. Adjuvant therapy included 8-month 3-drug chemotherapy for non anaplastic “local” tumor stag...