A total of 342 previously untreated eligible children were entered into the first Intergroup Ewing's Sarcoma Study (IESS) between May 1973 and November 1978. In group I institutions, patients were randomized between treatment 1 (radiotherapy to primary lesion plus cyclophosphamide, vincristine, dactinomycin, and Adriamycin [doxorubicin; Adria Laboratories, Columbus, OH] [VAC plus ADR]) or treatment 2 (same as treatment 1 without ADR), and group II institutions randomized patients between treatment 2 or treatment 3 (same as treatment 2 plus bilateral pulmonary radiotherapy [VAC plus BPR]). The percentages of patients relapse-free and surviving (RFS) at 5 years for treatments 1, 2, and 3 were 60%, 24%, and 44%, respectively. There was strong statistical evidence of a significant advantage in RFS for treatment 1 (VAC plus ADR) versus 2 (VAC alone) (P less than .001) and 3 (P less than .05) and also of treatment 3 versus 2 (P less than .001). Similar significant results were observed with respect to overall survival. Patients with disease at pelvic sites have significantly poorer survival at 5 years than those with disease at nonpelvic sites (34% v 57%; P less than .001). Among pelvic cases, there was no evidence of differing survival by treatment (P = .81), but among nonpelvic cases, there was strong evidence of differing survival by treatment (P less than .001). The overall percentage of patients developing metastatic disease was 44%; the percentages by treatments 1, 2, and 3 were 30%, 72%, and 42%, respectively. The overall incidence of local recurrence was 15%, and there was no evidence that local recurrence rate differed by treatment. Patient characteristics related to prognosis, both with respect to RFS and overall survival experience, were primary site (nonpelvic patients were most favorable) and patient age (younger patients were more favorable).

The Third National Wilms' Tumor Study sought to reduce treatment for low-risk patients and find better chemotherapy for those at high risk for relapse. Eligible patients (1439) were randomized according to stage (I-IV) and histology (favorable [FH] or unfavorable [UH]), and contributed data to survival and relapse-free survival (RFS) analyses. Four-year (postnephrectomy) survival percentages and randomized treatment regimens for low-risk patients were 96.5% for 607 Stage I/FH patients who received dactinomycin (Actinomycin D [AMD], Merck Sharp & Dohme, West Point, PA) and vincristine (VCR) for 10 weeks versus 6 months; 92.2% for 278 Stage II/FH patients; and 86.9% for 275 Stage III/FH patients who received AMD + VCR +/- Adriamycin (ADR, Adria Laboratories, Columbus, OH) for 15 months. Stage II/FH patients also had either zero or 2000 cGy irradiation (RT) postoperatively and Stage III/FH patients either 1000 or 2000 cGy. Four-year survival was 73.0% for 279 high-risk patients (any Stage IV, all UH) who received postoperative radiation therapy (RT) and AMD + VCR + ADR +/- cyclophosphamide (CPM). Statistical analysis of survival and RFS experience shows that the less intensive therapy does not worsen results for low-risk patients and CPM does not benefit those at high risk.

One-hundred-eighty-eight children up to 16 years of age were randomized in the second National Wilms' Tumor Study (NWTS) with tumors that were confined to the kidney and that had been totally excised (Group I). Most fared well whether treated for six or for 15 months with both actinomycin D (AMD) and vincristine (VCR). No postoperative radiation therapy (RT) was given. The two-year relapse-free survival (RFS) and two-year survival rates were 88 and 95%, respectively. Two-hundred-sixty-eight randomized patients with more advanced local lesions (Groups II and III) and 57 with distant metastases (Group IV) had postoperative RT and were scheduled for 15 months treatment with either AMD and VCR (Reg. C) or AMD plus VCR plus Adriamycin (Reg. D). The 77% two-year RFS rate for Reg. D was significantly different from the 63% with Reg. C. As in the first NWTS, patients with tumors of unfavorable histology (UH) had a significantly worse prognosis than those with favorable histology (FH), as did those with positive nodes. Survival rates at two years were 54% for UH vs. 90% for FH, and 54% vs. 82% for those with and without lymph node involvement.

The National Wilms' Tumor Study, initiated in 1969, tested competing treatment strategems for patients with tumors ranging from Group (Gp) I (tumors confined to the kidney and totally removed) to Gp IV (remote metastases present at diagnosis). Three hundred and fifty‐nine of 606 registered patients were randomized in the trial. Gp I patients under 2 years of age fared well whether postoperative radiation therapy (RT) was or was not added to 15 months' maintenance actinomycin D (AMD). Their prognosis was better than that for older cohorts similarly treated, in whom the difference in relapse rates between treatment groups were suggestive of an RT effect. Combined AMD and vincristine (VCR) gave better results than either agent alone in patients with more advanced tumors (Gps II and III) still confined to the abdomen, all of whom received postoperative RT as well. Preoperative VCR given Gp IV patients in addition to postoperative RT, AMD, and VCR did not improve results. The frequency of mesoblastic nephroma (1%), of bilateral tumors (5%), and of incorrect preoperative diagnosis of Wilms' tumor (5%), the toxicities of the various regimens, and other ancillary data are presented and discussed.

The results of this study suggest that genetic abnormalities play a prominent role in the development of an SMN after therapy for a primary RMS. Chemotherapy with an alkylating agent and radiotherapy play significant roles in the development of an SMN compared with patients who received only one of these therapeutic modalities.