Late effects in children treated with radiation therapy for Wilms' tumor

Purpose: To determine the frequency and types of late effects in children r eceiving radiation therapy (RT) for Wilms' tumor. Materials and Methods: From 1968 to 1994, 55 children received megavoltage RT at our institution as part of treatment for Wilms' tumor. A total of 42 (76.4%) have survived and have a minimum follow-up of 5 years. There were 2 5 female and 17 male patients with a median age at diagnosis of 48 months ( range, 7-126 months). There were 12 Stage I, eight Stage II, 15 Stage III, six Stage IV, and one Stage V patient. RT was delivered to the hemiabdomen in 36 and whole abdomen in six patients. RT dose was 1000-1200 cGy (Group A ) in 12, 1201-2399 cGy (Group B) in 11, and 2400-4000 cGy (Group C) in 19. Whole-lung RT was delivered to 13 patients either at diagnosis or pulmonary relapse. All patients received chemotherapy; the most common agents were a ctinomycin-D/vincristine/adriamycin in 13 and actinomycin-D/vincristine in 18. Median follow-up was 181 months (range, 60-306 months). Results: Of 42 patients, 13 (31.0%) did not have late effects of treatment. The number of patients who developed muscular hypoplasia, limb length ineq uality, kyphosis, and iliac wing hypoplasia were seven (16.7%), five (11.9% ), three (7.1%), and three (7.1%), respectively. Scoliosis was seen in 18 ( 42.9%) with only one patient requiring orthopedic intervention. Median time to development of scoliosis was 102 months, with a range of 16-146 months. The actuarial incidence of scoliosis at 5, 10, and 15 years after RT was 4 .8 +/- 3.3%, 51.8 +/- 9.0%, and 56.7 +/- 9.3%, respectively. Only one of 12 Group A patients developed scoliosis. The 10- and 15-year actuarial incide nces of scoliosis for Group A and B patients were 37.7 +/- 12.4% and 37.7 a 12.4%, whereas for Group C patients the incidences were 65.8 +/- 12.0% and 74.4 +/- 11.7% (p = 0.03, log rank test). The actuarial incidence of bowel obstruction at 5, 10, and 15 years was 9.5 +/- 4.5%, 13.0 +/- 5.6%, and 17 .0 +/- 6.5%. Of 23 patients, five irradiated within 10 days of surgery acid one of 19 irradiated after 10 days developed bowel obstruction (p = 0.09, log rank test). Three patients developed hypertension with normal blood ure a nitrogen (BUN) and creatinine levels; another patient had chronic renal i nsufficiency in a nonirradiated kidney. One patient developed diffuse inter stitial pneumonitis. Of the 19 female patients who have reached puberty, th ree have given birth, and 15 have regular and one has irregular menstrual p eriods. Four patients developed benign neoplasms; three were in the RT fiel d (two osteochondroma, one lipoma) and one outside (cervical intraepithelia l neoplasia II). There were three second malignancies (chronic myelogenous leukemia at 9 years, osteosarcoma at 11 years, and breast cancer at 25 year s after initial diagnosis of nephroblastoma); both solid malignancies occur red in the RT field. Conclusions: Late effects of therapy were seen in more than two thirds of c hildren treated for Wilms' tumor. Children treated with lower doses (<2400 cGy) had a lower incidence of scoliosis compared with those who received mo re than 2400 cGy. There is also a suggestion that the incidence is lower in patients who received 1000-1200 cGy. Severe physical and functional deform ity from RT was uncommon. (C) 2000 Elsevier Science Inc.