Primary Tumor

A. TNM Classification
1. Primary Tumor (T) Figure 25 - Primary tumor size (T) classification. (American Cancer Society, 2009)
Primary Tumor (T)
TX Primary tumor cannot be assessed.
T0 No evidence of primary tumor.
Tis Carcinoma in situ.
Tis (DCIS) DCIS
Tis (LCIS) LCIS
Tis (Paget) Paget’s disease of the nipple 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
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). Invasion of the dermis alone does not qualify as T4.
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.
Table 3 - Primary tumor (T), AJCC TNM classification.
(Edge, et al.,
N3c Metastases in ipsilateral supraclavicular lymph node(s).
Table 4 – Clinical assessment of regional lymph nodes (N), AJCC TNM classification.
(Edge, et al., 2011) Regional Lymph Nodes (N) - Pathological pNX Regional lymph nodes cannot be assessed (e.g., previously removed or not removed for pathologic study). pN0 No regional lymph node metastasis identified histologically.
Note: ITCs are defined as small clusters of cells ≤0.2 mm, or single tumor cells, or a cluster of 0.2 mm and/or > 200 cells but none > 2.0 mm). pN1a Metastases in 1 – 3 axillary lymph nodes, at least one metastasis > 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 – 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 – 9 axillary lymph nodes.
OR
Metastases in clinically detected internal mammary nodes in the absence of axillary lymph node metastases. pN2a Metastases in 4 – 9 axillary lymph nodes (at least 1 tumor deposit > 2