Clinical grouping of rhabdomyosarcoma by the intergroup rhabdomyosarcoma study group (IRSG)

Clinical group	Extent of disease/surgical result
I	A Localized tumor, confined to site of origin, completely resected
I	B Localized tumor, infiltrating beyond site of origin, completely resected
II	A Localized tumor, gross total resection, but with microscopic residual disease
	B Locally extensive tumor (spread to regional lymph nodes), completely resected
	C Locally extensive tumor (spread to regional lymph nodes), gross total resection, but microscopic residual disease
III	A Localized or locally extensive tumor, gross residual disease after biopsy only
III	B Localized or locally extensive tumor, gross residual disease after major resection (≥50% debulking)
IV	Any size primary tumor, with or without regional lymph node involvement, with distant metastases, irrespective of surgical approach to primary tumor

Adapted from:

Maurer HM, Beltangady M, Gehan EA, et al. The Intergroup Rhabdomyosarcoma Study-I. A final report. Cancer 1988; 61:209.
Crist W, Garnsey L, Beltangady M, et al. Prognosis in children with rhabdomyosarcoma: A report of the intergroup rhabdomyosarcoma studies I and II. Intergroup Rhabdomyosarcoma Committee. J Clin Oncol 1990; 8:443.
Crist W, Gehan EA, Ragab AH, et al. The Third Intergroup Rhabdomyosarcoma Study. J Clin Oncol 1995; 13:610.

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