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
Stage IIIB	T4	N0	M0	G2, G3
Stage IV	Any T	N1	M0	Any G
Stage IV	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