A total of 338 patients enrolled in Children 's Oncology Group ( COG ) study D9803 met the inclusion criteria for this analysis : ( 1 ) non-metastatic , initially unresected ( Group III ) ; ( 2 ) embryonal ( ERMS ) or alveolar ( ARMS ) histology ; ( 3 ) documented protocol week 12 response to induction chemotherapy ( excluding progressive disease ) based on anatomic imaging ( CT/MRI ) and ( 4 ) documented protocol therapy beyond week 12 .