Recent experience with Wilms' tumor: 1978-1991.

BACKGROUND: The treatment of Wilms' tumor has undergone major advances in the past four decades. Current therapy is based on both the stage and pathology of the tumor. We have reviewed our recent experience with this tumor to assess the results of treatment on protocols that generally avoid the use of doxorubicin.
METHODS: Between January 1978 and December 1991 we treated 114 children with renal tumors. Ninety-one (80%) had favorable histology Wilms' tumor and 23 (20%), unfavorable histology tumors (13 anaplastic Wilms' tumors, four clear cell tumors of the kidney, and six sarcomatous tumors with rhabdoid elements). Chemotherapy was divided into two eras: 1978-1982 (vincristine and actinomycin-D) and 1983-1991 [vincristine and actinomycin-D for all patients, and cyclophosphamide for those with favorable histology and metastatic disease (n = 13) and all patients with anaplastic histology (n = 13)]. Four patients with clear cell or rhabdoid/sarcomatous tumor, three of whom are disease-free, were treated with a five-drug regimen (vincristine, doxorubin, cyclophosphamide, platinum, and VP-16). Approximately two thirds of the patients received megavoltage radiotherapy to the tumor bed. Mean abdominal radiation doses from 1978 to 1982 were slightly higher than those used from 1983 to 1991 (2,597 +/- 782 cGy vs. 2,039 +/- 524 cGy, respectively).
RESULTS: No isolated local failures were observed in any favorable histology patient who received radiotherapy. Among the 91 patients with favorable histology, there was no statistically significant difference in event-free survival irrespective of stage. Outcome for patients with anaplastic or clear cell variants was not different from that for those patients with favorable histology, but there were only small numbers in these groups for comparison. Only children with a rhabdoid/sarcomatous variant demonstrated survival that was different from all others (p = 0.00). Our previously reported patients with stage I tumors (< 550 g) (n = 11) who were treated by nephrectomy only continue to have an excellent outcome (survival 100%).
CONCLUSIONS: Wilms' tumors remain highly curable. Some unfavorable histology tumors require intensive therapy. Others such as our stage I tumors may be best observed without adjuvant therapy to avoid the toxicity of treatment.