RADIOTHERAPY IN THE SIOP (INTERNATIONAL-SOCIETY-OF-PEDIATRIC-ONCOLOGY) NEPHROBLASTOMA STUDIES - A REVIEW

For decades radiation has generally been accepted as a valuable supple ment to surgery in the treatment of Wilms' tumor; unfortunately, it ma y produce undesirable late effects. It turned out, however, that when treatment is adjusted to known variables, the risk for late sequelae c an be diminished in some groups of children. SIOP clinical trials have been based on children with unilateral tumors of standard histology a nd free of metastasis at diagnosis. The first two clinical trials, SIO P-1 (started in 1971) and SIOP-2 (started in 1974), established the be neficial effect (such as less ruptures, lower stage) of preoperative r adiation and actinomycin D (AMD) in SIOP-2, with all children having r adiation therapy either preoperatively, postoperatively, or both. In t he SIOP-5 trial (started in 1977), preoperative radiation therapy and AMD were compared with preoperative chemotherapy resulting in only 50% of children having radiation. The result permitted disuse of preopera tive radiation in the SIOP-6 trial (started in 1980), where only one-t hird of the patients received postoperative radiation therapy. At pres ent, in the SIOP-9 trial (started in 1987), fewer than 20% of children are having radiotherapy. The survival rates meanwhile have been incre asing steadily from 64% in SIOP-1 to 84% in SIOP-6 for stages I, II, a nd III combined. (C) 1994 Wiley-Liss, Inc.