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 |