Purpose: Orbital rhabdomyosarcoma (RMS) historically has been associated with an excellent survival rate. The majority of patients are cured with the use of both chemotherapy and radiation therapy, but a significant number experience important late sequelae of treatment. In an attempt to determine optimal therapy in relation both to cure and to sequelae, the experience of the four international collaborative groups (Intergroup Rhabdomyosarcoma Study Group [IRSG], International Society of Paediatric Oncology [SIOP] Sarcoma Committee, German Collaborative Soft Tissue Sarcoma Group [CWS], and Italian Cooperative Soft Tissue Sarcoma Group [ICG] studies) was shared at an international workshop.
Patients and methods: A total of 306 eligible patients were identified from group records (186 from IRS, 43 from SIOP MMT, 40 from CWS, and 37 from ICG). Median age was 6.8 years, and median follow-up was 6.5 years. Eighty percent of patients received radiation therapy (RT) as part of primary therapy, but there were significant differences in the use of RT between the individual groups (93% in IRSG, 76% in ICG, and 70% in CWS, but only 37% in the SIOP MMT group).
Results: At 10 years, event-free and overall survival for the whole cohort were 77% (range, 71% to 81%) and 87% (range, 82% to 92%), respectively. There was no difference in overall survival between the collaborative groups regardless of differences in the use of initial RT. In total, 34 (12%) of 273 survivors had not received RT, although this varied between the different groups (41% in the SIOP MMT group, 20% in CWS, 7% in ICG, and 6% in IRSG). There was no difference in overall survival for the whole cohort regardless of whether radiotherapy was used as part of initial therapy (86% at 10 years for both).
Conclusion: These data suggest that a subset of patients with orbital RMS can be cured without systematic local therapy, although the total burden of treatment (primary therapy and treatment for relapse) must be taken into account when assessing the implications for late sequelae.