Stature loss following treatment for Wilms tumor

Background. The study was designed to estimate reduction in adult stature i nduced by megavoltage radiation therapy (RT) of the spine in children treat ed for Wilms tumor and to ascertain whether the dose reduction in successiv e National Wilms Tumor Study Group (NWTSG) trials has mitigated late effect s of RT in these children. Procedure. Effects of RT dose, age at treatment, and chemotherapy on stature of 2,778 children with Wilms or another solid tumor of the kidney were analyzed using statistical models accounting for t he dependence of height on gender and advancing age. Model predictions were validated by descriptive analysis of heights measured at 17 to 18 years of age for 205 patients. Results. Radiation-induced reductions below normal h eight depended on dose, portal size, and age at treat ment and were not aug mented by doxorubicin or cyclophosphamide. Younger children were more stron gly affected. Predicted height deficit at age 18 years was 1.8 cm for a chi ld treated with 10 Cy to the flank at age 4 years. Observed height deficits at age 17 to 18 years were 4.1 cm for 57 patients who received 15-24 Gy at a mean age of 55 months and zero for 16 children who received RT doses und er 15 Gy at a mean age of 83 months. Conclusions, Reduction in stature foll owing RT to the pediatric spine is dose- and age-dependent, persists into a dulthood, and is not exacerbated by doxorubicin or cyclophosphamide. Averag e height deficits observed at maturity for children receiving doses current ly recommended by the NWTSG are clinically nonsignificant. Med. Pediatr. On col. 36:295-304, 2001. (C) 2001 Wiley-Liss, Inc.