Primary tumor (T) | ||||
T category | T criteria | |||
TX | Primary tumor cannot be assessed | |||
T0 | No evidence of primary tumor | |||
T1 | Tumor 5 cm or less in greatest dimension | |||
T2 | Tumor more than 5 cm and less than or equal to 10 cm in greatest dimension | |||
T3 | Tumor more than 10 cm and less than or equal to 15 cm in greatest dimension | |||
T4 | Tumor more than 15 cm in greatest dimension | |||
Regional lymph nodes (N) | ||||
N category | N criteria | |||
N0 | No regional lymph node metastasis or unknown lymph node status | |||
N1 | Regional lymph node metastasis | |||
Distant metastasis (M) | ||||
M category | M criteria | |||
M0 | No distant metastasis | |||
M1 | Distant metastasis | |||
Definition of grade (G) | ||||
G | G definition | |||
GX | Grade cannot be assessed | |||
G1 | Total differentiation, mitotic count and necrosis score of 2 or 3 | |||
G2 | Total differentiation, mitotic count and necrosis score of 4 or 5 | |||
G3 | Total differentiation, mitotic count and necrosis score of 6, 7, or 8 | |||
Prognostic stage groups | ||||
When T is... | And N is... | And M is... | And grade is... | Then the stage group is... |
T1 | N0 | M0 | G1, GX | IA |
T2, T3, T4 | N0 | M0 | G1, GX | IB |
T1 | N0 | M0 | G2, G3 | II |
T2 | N0 | M0 | G2, G3 | IIIA |
T3, T4 | N0 | M0 | G2, G3 | IIIB |
Any T | N1 | M0 | Any G | IIIB |
Any T | Any N | M1 | Any G | IV |
Tumor differentiation | ||||
Tumor differentiation is histology specific and is generally scored as follows: | ||||
Differentiation score | Definition | |||
1 | Sarcomas closely resembling normal adult mesenchymal tissue (eg, low-grade leiomyosarcoma) | |||
2 | Sarcomas for which histologic typing is certain (eg, myxoid/round cell liposarcoma) | |||
3 | Embryonal and undifferentiated sarcomas, sarcomas of doubtful type, synovial sarcomas, soft tissue osteosarcoma, Ewing sarcoma/primitive neuroectodermal tumor (PNET) of soft tissue | |||
Mitotic count | ||||
In the most mitotically active area of the sarcoma, 10 successive high-power fields (HPF; one HPF at 400x magnification = 0.1734 mm2) are assessed using a 40x objective. | ||||
Mitotic count score | Definition | |||
1 | 0 to 9 mitoses per 10 HPF | |||
2 | 10 to 19 mitoses per 10 HPF | |||
3 | ≥20 mitoses per 10 HPF | |||
Tumor necrosis | ||||
Evaluated on gross examination and validated with histologic sections. | ||||
Necrosis score | Definition | |||
0 | No necrosis | |||
1 | <50% tumor necrosis | |||
2 | ≥50% tumor necrosis |
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