TNM Classification for Soft Tissue Sarcoma
The revised AJCC Cancer Staging Manual, Eighth edition classifies soft tissue sarcoma based on tumor-node-metastasis (TNM) and tumor grade (G). [1] The AJCC follows the grading system of the French Federation of Cancer Centers Sarcoma Group (FNCLCC). Tumor grade is based on cellular differentiation, mitotic rate, and extent of necrosis, as outlined in Table 1.
Table 1. Histologic Grade (G) for Soft Tissue Sarcoma (Open Table in a new window)
Tumor Differentiation | Mitotic Count | Tumor Necrosis |
Sarcoma closely resembling normal adult mesenchymal tissue (eg, low-grade leiomyosarcoma (1 point) | 0-9 mitoses per 10 high-power fields (HPF) (1 point) | No necrosis (0 points) |
Sarcomas for which histologic typing is certain (eg, myxoid/round cell liposarcoma) (2 points) | 10-19 mitoses per 10 HPF (2 points) | < 50% tumor necrosis (1 point) |
Embryonal and undifferentiated sarcomas, sarcomas of doubtful type, synovial sarcomas, soft tissue osteosarcoma, Ewing sarcoma/primative neuroectodermal tumor (PNET) of soft tissue (3 points) | ≥20 mitoses per 10 HPF (3 points) | ≥50% tumor necrosis (2 points) |
The scores for these variables are added to calculate the following G values:
-
GX - Grade cannot be assessed
-
G1 - Total score of 2 or 3
-
G2 - Total score of 4 or 5
-
G3 - Total score of 6 or higher
Histology and grade are critical components of staging. Lymph node involvement is not characteristic of most sarcomas except rhabdomyosarcoma and synovial, clear cell, vascular, and epithelioid sarcomas.
Separate staging systems have been created based on anatomic location and type as follows:
-
Soft tissue sarcoma of the head and neck
-
Soft tissue sarcoma of the trunk and extremities
-
Soft tissue sarcoma of the abdomen and thoracic visceral organs
-
Soft tissue sarcoma of the retroperitoneum
These guidelines do not pertain to the management of gastrointestinal stroma tumors (GISTs), rhabdomyosarcoma, Ewing sarcoma, desmoplastic round cell tumors, and primitive neuroectodermal tumors.
Soft tissue sarcoma of the head and neck
Soft tissue sarcoma of the head and neck is a new classification and anatomic staging and prognostic groups have not yet been defined due to a lack of data. The TNM and G classifications are provided in Tables 2 and 3 below. [2]
Table 2. TNM Classification for Soft Tissue Sarcoma of the Head and Neck (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T1 |
Tumor ≤ 2 cm |
T2 |
Tumor > 2 cm to ≤ 4 cm |
T3 |
Tumor > 4 cm |
T4 |
Tumor with invasion to adjoining structures |
T4a |
Tumor with orbital invation, skull base/dural invasion, invasion of central compartment viscera, involvement of facial skeleton, or invasion of pterygold muscles |
T4b |
Tumor with brain parenchymal invasion, carotid artery encasement, prevertebal muscle invasion, or central nervous system involvement via perineural spread |
Regional lymph nodes (N) |
|
NX |
Regional lymph nodes cannot be assessed |
N0 |
No regional lymph node metastasis |
N1 |
Regional lymph node metastasis |
Distant metastasis (M) |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
Table3. Histologic grade (Open Table in a new window)
Histologic grade (G) |
|
GX |
Grade cannot be assessed |
G1 |
Grade 1 |
G2 |
Grade 2 |
G3 |
Grade 3 |
Soft tissue sarcoma of the trunk and extremites
The TNM and G classifications and anatomic stage/prognostic groups are provided in Tables 4, 5 and 6 below. [2]
Table 4. TNM Classification for Soft Tissue Sarcoma of the Trunk and Extremities (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence for primary tumor |
T1 | Tumor ≤ 5 cm in greatest dimension |
T2 |
Tumor > 5 cm to ≤ 10 cm in greatest dimension |
T3 |
Tumor > 10 cm to ≤ 15 cm in greatest dimension |
T4 |
Tumor > 15 cm |
Regional lymph nodes (N) |
|
N0 |
No regional lymph node metastasis or nodes cannot be assessed |
N1 |
Regional lymph node metastasis |
Distant metastasis (M) |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
Table 5. Histologic grade (Open Table in a new window)
Histologic grade (G) |
|
GX |
Grade cannot be assessed |
G1 |
Grade 1 |
G2 |
Grade 2 |
G3 |
Grade 3 |
Table 6. Anatomic stage/prognostic groups (Open Table in a new window)
Stage |
T |
N |
M |
Histologic grade |
Stage IA |
T1 |
N0 |
M0 |
G1, GX |
Stage IB |
T2 |
N0 |
M0 |
G1, GX |
T3 |
N0 |
M0 |
G1, GX |
|
T4 | N0 | M0 | G1, GX | |
Stage II |
T1 |
N0 |
M0 |
G2, G3 |
Stage IIIA |
T2 |
N0 |
M0 |
G2, G3 |
Stage IIIB |
T3 |
N0 |
M0 |
G2, G3 |
T4 |
N0 |
M0 |
G2, G3 |
|
Stage IV |
Any T | N1 | M0 | Any G |
Any T |
Any N |
M1 |
Any G |
Soft tissue sarcoma of the abdomen and thoracic visceral organs
The TNM and G classifications are provided in Tables 7 and 8 below. There is currently no recommended prognostic stage grouping. [2]
Table 7. TNM Classification for Soft Tissue Sarcoma of the Abdomen and Thoracic Visceral Organs (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T1 | Organ confined |
T2 |
Tumor extends to tissue beyond organ |
T2a | Tumor invades serosa or visceral peritoneum |
T2b | Tumor extends beyond serosa (mesentery) |
T3 |
Tumor invades another organ |
T4 |
Multifocal tumor involvement |
T4a | Multifocal tumor involvement (2 sites) |
T4b | Multifocal tumor involvement (3-5 sites) |
T4c | Multifocal tumor involvement (> 5 sites) |
Regional lymph nodes (N) |
|
N0 |
No regional lymph node metastasis or nodes cannot be assessed |
N1 |
Regional lymph node metastasis |
Distant metastasis (M) |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
Table 8. Histologic grade (Open Table in a new window)
Histologic grade (G) |
|
GX |
Grade cannot be assessed |
G1 |
Grade 1 |
G2 |
Grade 2 |
G3 |
Grade 3 |
Soft tissue sarcoma of the retroperitoneum
The TNM and G classifications and anatomic stage/prognostic groups are provided in Tables 9, 10, and 11, below. [2]
Table 9. TNM Classification for Soft Tissue Sarcoma of the Retroperitoneum (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence for primary tumor |
T1 | Tumor ≤ 5 cm in greatest dimension |
T2 |
Tumor > 5 cm to ≤ 10 cm in greatest dimension |
T3 |
Tumor > 10 cm to ≤ 15 cm in greatest dimension |
T4 |
Tumor > 15 cm |
Regional lymph nodes (N) |
|
N0 |
No regional lymph node metastasis or nodes cannot be assessed |
N1 |
Regional lymph node metastasis |
Distant metastasis (M) |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
Table 10. Histologic grade (Open Table in a new window)
Histologic grade (G) |
|
GX |
Grade cannot be assessed |
G1 |
Grade 1 |
G2 |
Grade 2 |
G3 |
Grade 3 |
Table 11. Anatomic stage/prognostic groups (Open Table in a new window)
Stage |
T |
N |
M |
Histologic grade |
Stage IA |
T1 |
N0 |
M0 |
G1, GX |
Stage IB |
T2 |
N0 |
M0 |
G1, GX |
T3 |
N0 |
M0 |
G1, GX |
|
T4 | N0 | M0 | G1, GX | |
Stage II |
T1 |
N0 |
M0 |
G2, G3 |
Stage IIIA |
T2 |
N0 |
M0 |
G2, G3 |
Stage IIIB |
T3 |
N0 |
M0 |
G2, G3 |
T4 |
N0 |
M0 |
G2, G3 |
|
Any T | N1 | M0 | Any G | |
Stage IV |
Any T |
Any N |
M1 |
Any G |