Staging for soft tissue sarcoma

As well as the MSTS system for staging soft tissue sarcoma, there is an established American Joint Committee on Cancer Staging (AJCC) TNM system. This is in its seventh version.

Staging investigations typically involve local site imaging and CT of chest, possibly including the abdomen and pelvis. Nodal involvement is unusual, but may be more common in some types, such as clear cell sarcoma, epithelioid sarcoma and rhabdomyosarcoma.

The size cut off between T1 and T2 is 5cm, above which tumours are considered T2. Tumours above and not involving the deep fascia are considered superficial,  those involving or deep to the fascia are considered deep.

 

Definitions for staging

TX

Primary tumor cannot be assessed.

T0

No evidence of primary tumor.

T1

Tumor ≤5 cm in greatest dimension. (Size should be regarded as a continuous variable, and the measurement should be provided.)

T1a

Superficial tumor.b

T1b

Deep tumor.b

T2

Tumor >5 cm in greatest dimension.b

T2a

Superficial tumor.b

T2b

Deep tumor.

 

NX

Regional lymph nodes cannot be assessed.

N0

No regional lymph node metastasis.

N1b

Regional lymph node metastasis.

 

M0

No distant metastasis.

M1

Distant metastasis.

 

Stage IA

T1a

N0

M0

G1, GX

T1b

N0

M0

G1, GX

Stage IB

T2a

N0

M0

G1, GX

T2b

N0

M0

G1, GX

Stage IIA

T1a

N0

M0

G2, G3

T1b

N0

M0

G2, G3

Stage IIB

T2a

N0

M0

G2

T2b

N0

M0

G2

Stage III

T2a, T2b

N0

M0

G3

Any T

N1

M0

Any G

Stage IV

Any T

Any N

M1

Any G

 

Reference:

 AJCC: Soft tissue sarcoma. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 291-8.

 

 

 

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The Musculoskeletal Tumour Society staging system

The MSTS (Enneking) staging system for sarcomas is another exam classic.  This is a very straightforward system which allows the user to describe the extent of the tumour locally and systemically. Tumours are either low grade (Stage 1, <15% risk of metastasis), high grade (Stage 2, >15% risk of metastasis) or metastatic (Stage 3).

Intracompartmental tumours are classified as “A” and extracompartmental tumours as “B”.

For example, an osteosarcoma of the distal femur, which has an associated soft tissue mass but no detectable metastases would be staged as “2B” in this system.

Other systems include the AJCC system for staging.

Reference:

Enneking WF, Spanier SS, Goodman MA. Current concepts review. The surgical staging of musculoskeletal sarcoma. J Bone Joint Surg Am 1980;62(6):1027-30.