Breast
| T Category | Stage Category Definitions |
|---|---|
| TX | Primary tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| Tis | Carcinoma in situ |
| Tis (DCIS) | Ductal carcinoma in situ |
| Tis (LCIS) | Lobular carcinoma in situ |
| Tis (Paget's) | Paget’s disease of the nipple is NOT associated with invasive carcinoma and/or carcinoma in situ (DCIS and/or LCIS) in the underlying breast parenchyma. Carcinomas in the breast parenchyma associated with Paget's disease are categorized based on the size and characteristics of the parenchymal disease, although the presence of Paget's disease should still be noted |
| T1 | Tumor ≦ 20 mm in greatest dimension |
| T1mi | Tumor ≦ 1 mm in greatest dimension |
| T1a | Tumor > 1 mm but ≦ 5 mm in greatest dimension |
| T1b | Tumor > 5 mm but ≦ 10 mm in greatest dimension |
| T1c | Tumor > 10 mm but ≦ 20 mm in greatest dimension |
| T2 | Tumor > 20 mm but ≦ 50 mm in greatest dimension |
| T3 | Tumor > 50 mm in greatest dimension |
| T4 | Tumor of any size with direct extension to the chest wall and/or to the skin (ulceration or skin nodules)* |
| T4a | Extension to the chest wall, not including only pectoralis muscle adherence/invasion |
| T4b | Ulceration and/or ipsilateral satellite nodules and/or edema (including peau d'orange) of the skin which do not meet the criteria for inflammatory carcinoma |
| T4c | Both T4a and T4b |
| T4d | Inflammatory carcinoma** |
**Note: Inflammatory carcinoma is restricted to cases with typical skin changes involving a third or more of the skin of the breast. While the histologic presence of invasive carcinoma invading dermal lymphatics is supportive of the diagnosis, it is not required, nor is dermal lymphatic invasion without typical clinical findings sufficient for a diagnosis of inflammatory breast cancer.
| N Category | Stage Category Definitions |
|---|---|
| NX | Regional lymph nodes cannot be assessed (e.g., previously removed) |
| pNX* | Regional lymph nodes cannot be assessed (e.g., previously removed, or not removed for pathologic study) |
| N0 | No regional lymph node metastases |
| pN0 | No regional lymph node metastasis identified histologically |
| pN0(i-) | No regional lymph node metastases histologically, negative IHC |
| pN0(i+) | Malignant cells in regional lymph node(s) no greater than 0.2 mm (detected by H&E or IHC including ITC) |
| pN0(mol-) | No regional lymph node metastases histologically, negative molecular findings (RT-PCR) |
| pN0(mol+) | Positive molecular findings (RT-PCR), but no regional lymph node metastases detected by histology or IHC |
| N1 | Metastases to movable ipsilateral level I, II axillary lymph node(s) |
| pN1 | Micrometastases; or metastases in 1 to 3 axillary lymph nodes; and/or in internal mammary nodes with metastases detected by sentinel lymph node biopsy but not clinically detected** |
| pN1mi | Micrometastases (greater than 0.2 mm and/or more than 200 cells, but none greater than 2.0 mm) |
| pN1a | Metastases in 1 to 3 axillary lymph nodes, at least one metastasis greater than 2.0 mm |
| pN1b | Metastases in internal mammary nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected** |
| pN1c | Metastases in 1 to 3 axillary lymph nodes and in internal mammary lymph nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected** |
| pN2 | Metastases in 4 to 9 axillary lymph nodes; or in clinically detected*** internal mammary lymph nodes in the absence of axillary lymph node metastases |
| pN2a | Metastases in 4 to 9 axillary lymph nodes (at least one tumor deposit greater than 2.0 mm) |
| pN2b | Metastases in clinically detected*** internal mammary lymph nodes in the absence of axillary lymph node metastases |
| pN3 | Metastases in 10 or more axillary lymph nodes; or in infraclavicular (level III axillary) lymph nodes; or in clinically detected*** ipsilateral internal mammary lymph nodes in the presence of 1 or more positive level I, II axillary lymph nodes; or in more than 3 axillary lymph nodes and in internal mammary lymph nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected**; or in ipsilateral supraclavicular lymph nodes |
| pN3a | Metastases in 10 or more axillary lymph nodes (at least one tumor deposit greater than 2.0 mm); or metastases to the infraclavicular (level III axillary lymph) nodes |
| pN3b | Metastases in clinically detected*** ipsilateral internal mammary lymph nodes in the presence of 1 or more positive axillary lymph nodes; or in more than 3 axillary lymph nodes and in internal mammary lymph nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected** |
| pN3c | Metastases in ipsilateral supraclavicular lymph nodes |
**Note: Not clinically detected is defined as not detected by imaging studies (excluding lymphoscintigraphy) or not detected by clinical examination.
***Note: Clinically detected is defined as detected by imaging studies (excluding lymphoscintigraphy) or by clinical examination and having characteristics highly suspicious for malignancy or a presumed pathologic macrometastasis based on fine needle aspiration biopsy with cytologic examination. Confirmation of clinically detected metastatic disease by fine needle aspiration without excision biopsy is designated with an (f) suffix, for example, cN3a(f). Excisional biopsy of a lymph node or biopsy of a sentinel node, in the absence of assignment of a pT, is classified as
a clinical N, for example, cN1. Information regarding the confirmation of the nodal status will be designated in sitespecific factors as clinical, fine needle aspiration, core biopsy, or sentinel lymph node biopsy. Pathologic classification (pN) is used for excision or sentinel lymph node biopsy only in conjunction with a pathologic T assignment.
Note: Isolated tumor cell clusters (ITC) are defined as small clusters of cells not greater than 0.2 mm, or single tumor cells, or a cluster of fewer than 200 cells in a single histologic cross-section. ITCs may be detected by routine histology or by immunohistochemical (IHC) methods. Nodes containing only ITCs are excluded from the total positive node count for purposes of N classification but should be included in the total number of nodes evaluated
| M Category | Stage Category Definitions |
|---|---|
| M1 | Distant detectable metastases as determined by classic clinical and radiographic means and/or histologically proven larger than 0.2 mm |
| Stage | T | N | M |
|---|---|---|---|
| 0 | Tis | N0 | M0 |
| IA | T1* | N0 | M0 |
| IB | T0 | N1mi | M0 |
| IB | T1* | N1mi | M0 |
| IIA | T0 | N1** | M0 |
| IIA | T1* | N1** | M0 |
| IIA | T2 | N0 | M0 |
| IIB | T2 | N1 | M0 |
| IIB | T3 | N0 | M0 |
| IIIA | T0 | N2 | M0 |
| IIIA | T1* | N2 | M0 |
| IIIA | T2 | N2 | M0 |
| IIIA | T3 | N1 | M0 |
| IIIA | T3 | N2 | M0 |
| IIIB | T4 | N0 | M0 |
| IIIB | T4 | N1 | M0 |
| IIIB | T4 | N2 | M0 |
| IIIC | Any T | N3 | M0 |
| IV | Any T | Any N | M1 |
** T0 and T1 tumors with nodal micrometastases only are excluded from Stage IIA and are classified Stage IB.
