Primary lung metastases in pediatric malignant non-Wilms renal tumors: data from SIOP 93-01/GPOH and SIOP 2001/GPOH.

Malignant non-Wilms renal tumors (NWRT) are a small but relevant subgroup of renal neoplasms in children. In this study we analyzed corresponding data from the trials SIOP 93-01/GPOH and SIOP 2001/GPOH of the Society of Pediatric Oncology and Hematology.Data of 22 patients with NWRT and primary lung metastases were retrospectively reviewed. Analyses included epidemiology, tumor characteristics, chemotherapy, local treatment, and outcome.The following diagnoses were registered: Malignant Rhabdoid tumor of the kidney (MRTK, n=15), Renal-cell carcinoma (RCC, n=3), Clear-cell sarcoma of the kidney (CCSK, n=3), and primitive neuro ectodermal tumor (PNET, n=1). Median age of patients at diagnosis was 14 months. Overall survival was 36.36% (8/22). Of the 15 children with MRTK 3 survived, 3/3 patients with RCC, 1/3 patients with CCSK, and 1/1 patient with PNET survived. Lung metastases disappeared in 6 patients after initial chemotherapy, 6/8 patients undergoing local treatment of lung metastases (surgery, irradiation, or both) achieved complete remission. Only patients with complete clearance of lung lesions, either through neoadjuvant chemotherapy or subsequent local treatment, survived. Mean Follow up was 31 months (1-137).Survival of patients with stage IV NWRT is dismal. Complete removal of lung metastases seems mandatory for survival. An aggressive diagnostic and therapeutic approach seems justified in affected children.

Update on relapses in unilateral nephroblastoma registered in 3 consecutive SIOP/GPOH studies - a report from the GPOH-nephroblastoma study group.

INTRODUCTION: Treatment and stratification of progressive/relapsed unilateral nephroblastoma (PD) has significantly evolved over the last 20 years. Early PD (≤ 6 months), initial high risk histology, local stage III, multiple site PD and stage IV have been implemented as high risk classification factors and novel drugs have been introduced. PATIENTS AND METHODS: We analysed all 251 patients having had a unilateral nephroblastoma (Stage I-IV) and progressive disease who had been treated according to SIOP9/GPO (n = 77), SIOP93-1/GPOH (n = 93) and SIOP2001/GPOH (n = 81) initially. RESULTS: 3y-overall survival (OS) increased from 43% to 61% and 59% respectively (both p<0.01). 3y-OS for localized stage I-III rose from 43% to 65% and 68% respectively while only little improvement can be seen for initial stage IV patients with 43%, 53% and 44% respectively. Multivariate analysis confirmed high risk histology, local stage III, shorter time to PD, combined relapse as independent risk factors. 26 patients had received high-dose chemotherapy showing 64% 3y-OS compared to 54% for all non-transplanted (p=0.11). CONCLUSION: Structuring the treatment of progressive nephroblastoma as well as introducing new drugs have improved the outcome significantly. However improvement is depending on the specific risk profile. Very high risk tumours are often resistant to conventional treatment, hence an international uniform treatment concept is needed to achieve conclusive results in this small group.