| TX |
Primary tumor cannot be assessed |
| T0 |
No evidence of primary tumor |
| Tis (DCIS) |
Ductal carcinoma in situ
|
| Tis (Paget's) |
Paget's disease of nipple NOT associated with invasive carcinoma and/or carcinoma in situ (DCIS) in underlying breast parenchyma. Carcinomas in breast parenchyma associated with Paget disease are categorized based on size and characteristics of parenchymal disease, although presence of Paget 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 (round any measurement 1.0–1.9 mm to 2 mm) |
| 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 chest wall and/or to skin (ulceration or macroscopic nodules); invasion of dermis alone does not qualify as T4 |
| T4a |
Extension to chest wall, not including only pectoralis muscle adherence/invasion |
| T4b |
Ulceration and/or ipsilateral macroscopic satellite nodules and/or edema (including peau d'orange) of skin, which do not meet criteria for inflammatory carcinoma |
| T4c |
Both T4a and T4b |
| T4d |
Inflammatory carcinoma |
