|
Stage Information
Terms used in this summary section are defined below in Table 1.
Table 1. Definition of Terms
|
Term
|
Definition
|
| Favorable site |
Orbit; nonparameningeal head and neck; genitourinary excluding kidney, bladder, and prostate; biliary tract. |
| Unfavorable site |
Any site not considered favorable. |
| T1 |
Tumor confined to anatomic site of origin. |
| T2 |
Tumor extension and/or fixative to surrounding tissue. |
| a |
Tumor ≤5 cm in maximum diameter. |
| b |
Tumor >5 cm in maximum diameter. |
| N0 |
No clinical regional lymph node involvement. |
| N1 |
Clinical regional lymph node involvement. |
| NX |
Regional lymph nodes not examined; no information. |
| M0 |
No metastatic disease. |
| M1 |
Metastatic disease. |
Staging of rhabdomyosarcoma is relatively complex. The process includes:
- Assigning a local tumor group (status postsurgical resection/biopsy).
- Assigning stage (consider site, size, group, presence/absence of metastases).
- Assigning a risk group (consider stage, group, and histology).
As noted previously, prognosis for children with rhabdomyosarcoma is dependent
on the primary site, size, group, and histologic subtype. Favorable
prognostic groups have been identified by previous Intergroup Rhabdomyosarcoma
Studies (IRS), and treatment plans have been designed based on assignment of
patients to different groups based on prognosis. The IRS-I, IRS-II, and IRS-III studies prescribed treatment plans based on a
surgicopathologic grouping system. In this system, groups are defined by the
extent of disease and by the extent of initial surgical resection after
pathologic review of the tumor specimen(s). The definitions of these
groups in the IRS-I, IRS-II, and IRS-III studies are given in Table 2 below.[1,2]
Table 2. IRS Group Surgicopathologic Grouping System
|
Group
|
Definition
|
| I [Note: Approximately 13% of all patients are in this group.] |
A localized tumor that is completely removed with pathologically clear margins and no regional lymph node involvement. |
| II [Note: Approximately 20% of all patients are in this group.] |
A localized tumor that is grossly removed with: (A) microscopic disease at the margin, (B) involved, grossly removed regional lymph nodes, or (C) both A and B. |
| III [Note: Approximately 48% of all patients are in this group.] |
A localized tumor with gross residual disease after incomplete removal or biopsy only. |
| IV [Note: Approximately 18% of all patients are in this group.] |
Distant metastases are present at diagnosis. |
The Intergroup Rhabdomyosarcoma Study Group (IRSG) has merged with the National
Wilms Tumor Study Group and with the two large cooperative pediatric
cancer treatment groups to form the Children’s Oncology Group (COG). New
protocols for children with soft tissue sarcoma are developed by the Soft
Tissue Sarcoma Committee of the COG (STS-COG).
Current STS-COG protocols for rhabdomyosarcoma utilize a TNM-based
pretreatment staging system which incorporates the surgicopathologic group, primary tumor site, regional lymph node status, and the presence or
absence of metastases.
This staging system is described in Table 3 below.[3,4]
Table 3. STS-COG Pretreatment Staging System
|
Stage
|
Sites of Primary Tumor
|
Tumor Size
|
Regional Lymph Nodes
|
Distant Metastasis
|
| 1 |
Favorable sites |
Any size |
N0 or N1 or NX |
M0 |
| 2 |
Unfavorable sites |
T1a or T2a |
N0 or NX |
M0 |
| 3 |
Unfavorable sites |
T1a, T2a |
N1 |
M0 |
| T1b, T2b |
N0 or N1 or NX |
| 4 |
Any site |
Any size |
N0 or N1 |
M1 |
Following stage assignment, a risk group is assigned. This takes into account stage, group, and histology. Patients are classified for protocol purposes as low risk,
intermediate risk, or high risk.[5,6] Treatment assignment is based on risk group. Table 4 shows the current risk group classification.
Table 4. IRSG Rhabdomyosarcoma Risk Group Classification
|
Risk Group
|
Histology
|
Stage
|
Group
|
| 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 |
[Note: Since 2006, patients with undifferentiated sarcoma are treated on the STS-COG protocol for non-rhabdomyosarcomatous soft tissue sarcoma.]
References
-
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.
[PUBMED Abstract]
-
Crist W, Gehan EA, Ragab AH, et al.: The Third Intergroup Rhabdomyosarcoma Study. J Clin Oncol 13 (3): 610-30, 1995.
[PUBMED Abstract]
-
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.
[PUBMED Abstract]
-
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.
[PUBMED Abstract]
-
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.
[PUBMED Abstract]
-
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.
[PUBMED Abstract]
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