Interstitial brachytherapy for pediatric soft tissue sarcoma: Evolving practice over three decades and long-term outcomes.

Abstract

Evaluate long-term clinical outcomes, adverse effects, and evolving practice of interstitial brachytherapy (BT) for pediatric soft tissue sarcomas (STS). From September 1984 to December 2014, 105 children (median age 10 years) were included. There were 60 males and 45 females. The majority (74%) had primary lesions. Synovial sarcoma (22%) was the most frequent histology. Treatment included wide local excision and BT with or without external beam radiotherapy (EBRT). Eighty-five (81%) received BT alone. After a median follow-up of 65 months, local control (LC), disease-free survival (DFS), and overall survival (OS) at 10 years were 83, 66, and 73%, respectively. On univariate analysis, LC was superior with tumors<5cm versus>5cm (93%vs. 75%, P=0.10), Grade I/II versus Grade III tumors (97%vs. 73%, P=0.01), nonround cell versus round cell histology (89%vs. 72%, P=0.03), and trunk/extremity versus head and neck/genitourinary sites (87%vs. 57%, P=0.0001). On multivariate analysis tumor size (P=0.03) and location (P=0.002) retained significance. Children receiving BT alone had comparable LC to those receiving BT and EBRT (84%vs. 80%, P=0.43). There was no difference in LC between LDR versus HDR BT (86%vs. 83%, P=0.30). Wound complications were seen in 6%. Subcutaneous fibrosis (25%), limb edema (6%), skeletal abnormalities (3%), and neuropathy (1%) were the late complications. One child (0.9%) developed a second malignancy after 7 years. Interstitial BT with or without EBRT results in excellent outcomes. Radical BT alone, when used judiciously, results in excellent local control and function with minimal treatment-related morbidity.