Long-term Results of Radiation Therapy for Rhabdomyosarcoma in Very Young Children

To examine patterns of failure and late effects in children less than 3 years of age treated with multimodality therapy for rhabdomyosarcoma (RMS). Between 1991 and 2011, 48 patients ≤36 months received chemotherapy and radiation therapy (RT) for definitive treatment. Thirty-seven patients also underwent surgery with or without intraoperative radiation therapy (IORT) (n = 12). Median age was 17 (0-35) months. Unfavorable characteristics were as follows: 31% alveolar histology, 75% Group III disease, and 15% Group IV disease. Primary site was unfavorable in 77%: pelvis (n = 11), extremity (n = 10), parameningeal (n = 10), trunk (n = 6), and bladder/prostate (n = 4). The remainder had disease in the orbit (n = 4) and head-and-neck (n = 3). Median time to RT was 21 weeks. Median external beam RT (EBRT) dose was 41.4 (25.2-54) Gy in non-IORT patients. Patients receiving IORT (4-15 Gy) received a reduced median EBRT dose of 36 (24-45) Gy. Late effects were examined in 22 of 31 surviving patients with detailed follow-up. With median follow-up of 5 years (range, 1-22 years) in surviving patients, 5-year actuarial local control was 91% and overall survival was 64% for all patients. Among 22 patients with long term follow-up, median 8 (2-22) years, late effects depended on primary tumor site. Patients receiving pelvic RT (n = 6) experienced gastrointestinal dysfunction (n = 5), recurrent urinary tract infections (n = 3), and leg length inequality with scoliosis (n = 1), while those receiving RT to the head-and-neck (n = 11) experienced endocrine dysfunction (n = 4), cataracts and/or visual impairment (n = 5), chronic otitis/sinusitis (n = 3) and facial asymmetry (n = 5). One patient with a primary chest wall tumor developed mild cardiopulmonary dysfunction. One patient is receiving treatment for secondary AML. No secondary solid tumors have been reported. Although RT produces excellent local control in RMS, it is often avoided in very young children because of fear of late effects. In our experience, very young children can tolerate and benefit from risk-adapted RT often in combination with surgery and IORT. Site-related late-effects are generally compatible with a good quality of life.