Late effects of radiotherapy for pediatric extremity sarcomas.

PURPOSE: To determine the long-term effects of radiotherapy (RT) in children treated for extremity sarcoma. PATIENTS AND METHODS: Between 1964 and 1997, 15 of 33 children treated with RT for extremity sarcomas at the University of Iowa have survived with a median follow-up was 20 years (range, 6-36 years). There were 10 boys and 5 girls with a median age of 13 years (range, 3.5-20 years) at the time of irradiation. The diagnosis was Ewing's sarcoma in 8 (53%), synovial sarcoma in 4 (27%), alveolar rhabdomyosarcoma in 2, and fibrosarcoma in 1. Location of primary tumor was lower extremity in 10 (67%) and upper extremity in 5 (33%). RT was given as the definitive therapy for 9 children (median dose, 55.8 Gy; range, 45-66 Gy) and as an adjuvant postoperative treatment in 6 (median, 63 Gy; range, 41.4-66.4 Gy). (60)Co was used in 6 (40%), 4 mV in 4, 6 mV in 2, and 250 kV photons in 2 patients; 1 child was treated with a combination of 12 and 15 MeV electrons for a Ewing's sarcoma of the distal femur. Another child had a 25 Gy intraoperative RT boost after 41.4 Gy conventional RT. Late effects to the muscle, soft tissue, and growing bone were assessed using the objective portion of the LENT-SOMA scale proposed by the Late Effects Consensus Conference.
RESULTS: Late effects were seen in all patients and included atrophy in 12 (80%), fibrosis in 12 (80%), bone growth abnormalities in 10 (67%), impairment of mobility and extremity function in 6 (40%), edema in 3 (20%), and peripheral nerve injury in 2 (13%). Ten of 15 (67%) children had Grade 1 or 2 growing bone, muscle, soft tissue, or peripheral nerve complications. Two patients (13%) had a Grade 3 mobility and extremity function score and had moderate to severe limitation of movement. Two children (13%) required epiphysiodesis because of a shorter treated leg. The patient who received an intraoperative RT boost of 25 Gy developed sensory dysfunction of the ulnar nerve 11 years after RT. Another developed radial nerve palsy 3 years after marginal resection and postoperative RT and required tendon transfer repair. One patient had radiation-induced vasculitis with popliteal artery thrombosis 23 years after RT. Five (33%) developed a fracture of the irradiated bone at a median time of 8 years after RT (range: 9 months to 22.2 years); all had Ewing's sarcoma, and 3 of these patients were subsequently found to have a secondary bone cancer (osteosarcoma 2, malignant fibrous histiocytoma 1) in the RT field. One of these patients also developed breast cancer 26 years after lung RT for metastatic Ewing's sarcoma. Overall, 11 surgical procedures in 8 children were performed to correct a limb preservation treatment toxicity.
CONCLUSIONS: Although most children treated with RT for a pediatric extremity sarcoma have minimal late toxicity by LENT-SOMA scale, approximately half required a surgical procedure to correct a late effect. A fracture in the irradiated bone may be the presenting sign or may precede a radiation-induced bone malignancy, as seen in 3 of the patients in this study.