How is pediatric rhabdomyosarcoma (RMS) staged?

Updated: Mar 28, 2019
  • Author: Roshni Dasgupta, MD, MPH; Chief Editor: Eugene S Kim, MD, FACS, FAAP  more...
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Answer

Once the diagnosis of RMS has been made, the tumor should be staged. The staging system currently used for RMS is the Lawrence-Gehan staging system, which is initiated preoperatively and then completed after resection. [26] The four stages and the associated primary disease sites may be summarized as follows:

  • Stage 1 - Orbit/eyelid, head and neck (excluding parameningeal [PM]), genitourinary (excluding bladder/prostate)
  • Stage 2 - Bladder/prostate, extremity, PM, other (eg, trunk, retroperitoneum), smaller than 5 cm
  • Stage 3 - Bladder/prostate, extremity, PM, other (eg, trunk, retroperitoneum), larger than 5 cm
  • Stage 4 - All others

The staging is explained in greater detail in Tables 1 and 2 below.

Table 1. TNM Classification of Rhabdomyosarcoma (Open Table in a new window)

Tumor (T)

T1

T1a

T1b

Tumor confined to site of origin

< 5 cm

≥5 cm

 

T2

T2a

T2b

Tumor extending into surrounding tissue

< 5 cm

≥5 cm

Node (N) N0 No lymph node involvement
  N1 Clinical involvement of lymph nodes
  NX Unknown lymph node status
Metastasis (M) M0 No metastasis
  M1 Metastasis present

Table 2. Pretreatment Staging of Rhabdomyosarcoma. (Open Table in a new window)

Stage

Sites

T

Size

N

M

1

Orbit, head/neck (no parameningeal involvement), genitourinary (no bladder/prostate involvement)

T1 or T2

< 5 cm or ≥5 cm

N0 or N1 or Nx

M0

2

Bladder/prostate, extremity, cranial, head/neck parameningeal, other (trunk, retroperitoneum, thorax)

T1 or T2

< 5 cm

N0 or Nx

M0

3

Bladder/prostate, extremity, cranial, head/neck parameningeal, other (trunk, retroperitoneum, thorax)

T1 or T2

< 5 cm

N1

M0

≥5 cm N0 or N1 or Nx M0

4

Any

T1 or T2

< 5 cm or ≥5 cm

N0 or N1

M1

The Intergroup Rhabdomyosarcoma Study Group (IRSG) postsurgical pathologic grouping is as follows:

  • Group I - Localized disease, completely resected (clear margins, negative regional nodes)
  • Group II - Microscopic disease remaining (at margins or in regional nodes)
  • Group III - Incomplete resection or biopsy findings indicating gross residual disease (locally or in regional nodes)
  • Group IV - Distant metastases present at onset

Several studies have suggested that a cutoff tumor size of 5 cm may not be the best tool for staging pediatric RMS. Owing to variations in the body surface area (BSA) of children, the tumor size in relation to the patient’s BSA and volumetric measurements may be more useful in staging. [27]


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