Treatment of Nonmetastatic Cranial Parameningeal Rhabdomyosarcoma in Children Younger Than 3 Years Old: Results From International Society of Pediatric Oncology Studies MMT 89 and 95

Purpose To explore a strategy by which radiotherapy (RT) could be avoided in the treatment of young children with parameningeal rhabdomyosarcoma ( PM RMS). Patients and Methods Fifty-nine children (median age, 2 years 3 months) with nonmetastatic cranial PM RMS were treated in the International Society of Pediatric Oncology MMT 89 and 95 trials between 1989 and 2003. Results Five-year EFS and OS rates were 46% and 54%, respectively, for the whole group. No standard clinical or pathologic variables had prognostic impact. Fifty (85%) of 59 patients achieved complete local control either with (n = 28) or without (n = 22) RT administered as part of their primary treatment. Nine patients (15%) did not achieve local control (four of whom had had RT), and all died. Patients who received RT had a significantly superior 5-year EFS rate compared with patients who did not receive RT (59% v 28%, respectively). Twenty-three patients (48%) experienced relapse at a median interval of 15 months. Ultimately, only seven patients (12%) were cured without RT, although this represented 32% of those who achieved local control with initial chemotherapy. Conclusion Despite concerns about the late effects of its use in young children, cure of PM RMS remains unlikely without systematic use of RT. The accurate prediction of the small subset of patients who achieve local control without RT and who do not experience relapse would provide an opportunity for a minority of patients to avoid RT.