Late Toxicity in Wilms Tumor Patients Treated With Radiotherapy at 15 Years of Median Follow-up

Background: We report the radiation-induced late morbidity observed in our prospective series of Wilms tumor patients treated at the Second University of Naples. Methods: From April 1981 to April 2000, 98 patients were referred at our institution for treatment of Wilms tumor. Among them, 51 underwent radiotherapy and 34 patients had a minimum follow-up of 5 years. Doses of irradiation and treatment portals were those recommended by the guidelines of the Italian Association of Haematology and Paediatric Oncology according to risk stratification. All eligible patients were reviewed for follow-up every 6 months. Median follow-up was 181 months (range 60 to 264 months). Results: Eleven out of 34 patients (32%) did not suffer from any significant late side effect. Out of the remaining 23 (68%), 14 (41%) suffered from scoliosis presenting between 60 and 180 months from completion of treatment. Muscular hypoplasia, length inequality, kyphosis, and iliac wing hypoplasia were seen respectively, in 4 (12%), 4 (12%), 5 (15%), and 3 (9%) patients. The incidence of intestinal occlusion was 20%. One patient had chronic renal insufficiency. Four out of 13 female patients reported ovarian failure. Three out of the 7 patients who had radiotherapy to the lung developed radiation-pneumonitis. Radiation-induced heart disease was seen in 3 (9%) patients. Three patients (9%) suffered from second malignancies arising within the irradiated volume. Conclusions: Our data confirm the high incidence of late radiation morbidity in patients undergoing adjuvant radiotherapy for Wilms tumor. For most organ systems there is a correlation between total dose, morbidity rates, and degree of severity.