Etoposide in relapsed or refractory Wilms' tumor: a phase II study by the French Society of Pediatric Oncology and the United Kingdom Children's Cancer Study Group.

PURPOSE: Despite a high cure rate of approximately 85% in Wilms' tumor by multimodality therapy, to date only four drugs are known to be active against such tumors. There is a clear need for new active drugs. PATIENTS AND METHODS: Thirty-one patients with relapsed or refractory Wilms' tumor from three British and 14 French centers were treated with intravenous (IV) etoposide 200 mg/m2 daily for 5 days. Original stage was I (n = 3), II (n = 7), III (n = 9), IV (n = 10), and V (n = 2). Prior chemotherapy, administered initially or at relapse, included vincristine and dactinomycin in all cases, doxorubicin or epirubicin in 30, and ifosfamide in 20. Sites of relapse or resistant disease were lung in 13, abdomen or pelvis in six, liver in one, and multiple in 11. When entered onto the study, 12 patients were in first relapse, 10 in second relapse, and four in third or more relapse. Five had never obtained a complete remission. All but two (progressing) patients received two courses of etoposide, the second course being administered at day 21.
RESULTS: A complete response (CR) was documented in two patients, partial response (PR) in 11, stable disease in 10, and progressive disease (PD) in eight. The duration of response could not be evaluated, because all responding patients were subsequently treated with multimodality therapy. The major toxicities observed were neutropenia and thrombocytopenia, but most patients had been heavily pretreated. No toxic death clearly associated with etoposide was noted.
CONCLUSION: It is concluded that etoposide in this schedule is an active agent in Wilms' tumor and should be considered for inclusion in regimens for high-risk patients, such as those with metastatic disease at diagnosis and those who relapse after multiagent chemotherapy.