Table 3. Soft Tissue Sarcoma Committee of the Children's Oncology Group: Surgical-pathologic Group System
|I||Approximately 13%||Localized tumor, completely removed with microscopically clear margins and no regional lymph node involvement. Lymph node biopsy or sampling is encouraged if lymph nodes are clinically or radiographically suspicious.|
|II||Approximately 20%||Localized tumor, completely removed with: (a) microscopic disease at the margin, (b) regional disease with involved, grossly removed regional lymph nodes without microresidual disease,or(c) regional disease with involved nodes, grossly removed but with microscopic residual and/or histologic involvement of the most distal node from the primary tumor.|
|III||Approximately 48%||Localized tumor, incompletely removed with gross, residual disease after: (a) biopsy only,or(b) gross major resection of the primary tumor (>50%).|
|IV||Approximately 18%||Distant metastases are present at diagnosis. This category includes: (a) radiographically identified evidence of tumor spread,and(b) positive tumor cells in cerebral spinal fluid, pleural, or peritoneal fluids, or implants in these regions.|
After patients are categorized by Stage and Surgical-pathologic Group, a Risk Group is assigned. This takes into account Stage, Group, and histology. Patients are classified for protocol purposes as having a low risk, intermediate risk, or high risk of disease recurrence.[9,10] Treatment assignment is based on Risk Group, as shown in Table 4. To be designated as alveolar, the tumor must have greater than 50% alveolar elements; if the alveolar component is 50% or less, the tumor is considered embryonal.
Table 4. Soft Tissue Sarcoma Committee of the Children's Oncology Group: Rhabdomyosarcoma Risk Group Classification
|Low risk||Embryonal||1||I, II, III|
|Embryonal||2, 3||I, II|
|Intermediate risk||Embryonal||2, 3||III|
|Alveolar||1, 2, 3||I, II, III|
|High risk||Embryonal or Alveolar||4||IV|
Since 2006, patients with undifferentiated sarcomas are treated on the COG-STS protocol for nonrhabdomyosarcomatous soft tissue sarcoma. Refer to the PDQ summary on Childhood Soft Tissue Sarcoma for more information.
- Kayton ML, Delgado R, Busam K, et al.: Experience with 31 sentinel lymph node biopsies for sarcomas and carcinomas in pediatric patients. Cancer 112 (9): 2052-9, 2008.
- Völker T, Denecke T, Steffen I, et al.: Positron emission tomography for staging of pediatric sarcoma patients: results of a prospective multicenter trial. J Clin Oncol 25 (34): 5435-41, 2007.
- Tateishi U, Hosono A, Makimoto A, et al.: Comparative study of FDG PET/CT and conventional imaging in the staging of rhabdomyosarcoma. Ann Nucl Med 23 (2): 155-61, 2009.
- Baum SH, Frühwald M, Rahbar K, et al.: Contribution of PET/CT to prediction of outcome in children and young adults with rhabdomyosarcoma. J Nucl Med 52 (10): 1535-40, 2011.
- Lawrence W Jr, Gehan EA, Hays DM, et al.: Prognostic significance of staging factors of the UICC staging system in childhood rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study (IRS-II). J Clin Oncol 5 (1): 46-54, 1987.
- Lawrence W Jr, Anderson JR, Gehan EA, et al.: Pretreatment TNM staging of childhood rhabdomyosarcoma: a report of the Intergroup Rhabdomyosarcoma Study Group. Children's Cancer Study Group. Pediatric Oncology Group. Cancer 80 (6): 1165-70, 1997.
- Crist WM, Garnsey L, Beltangady MS, et al.: Prognosis in children with rhabdomyosarcoma: a report of the intergroup rhabdomyosarcoma studies I and II. Intergroup Rhabdomyosarcoma Committee. J Clin Oncol 8 (3): 443-52, 1990.
- Crist W, Gehan EA, Ragab AH, et al.: The Third Intergroup Rhabdomyosarcoma Study. J Clin Oncol 13 (3): 610-30, 1995.
- Raney RB, Anderson JR, Barr FG, et al.: Rhabdomyosarcoma and undifferentiated sarcoma in the first two decades of life: a selective review of intergroup rhabdomyosarcoma study group experience and rationale for Intergroup Rhabdomyosarcoma Study V. J Pediatr Hematol Oncol 23 (4): 215-20, 2001.
- Breneman JC, Lyden E, Pappo AS, et al.: Prognostic factors and clinical outcomes in children and adolescents with metastatic rhabdomyosarcoma--a report from the Intergroup Rhabdomyosarcoma Study IV. J Clin Oncol 21 (1): 78-84, 2003.