SEER Training Modules


Criteria for TNM Clinical Staging:

Physical examination; palpation of breast, axillary, supraclavicular and cervical nodes; pathologic examination of breast or other tissue to establish a diagnosis of cancer, including size of tumor, chest wall invasion, and presence or absence of positive nodes and distant metastases.

Criteria for TNM Pathologic Staging:

Removal of all primary tumor (no tumor at any margin of resection on gross examination) and at least Level I nodes (lateral to lateral border of pectoralis minor—at least 6 nodes in this area).

Brief Summaries of 6th Edition Categories
Tis In situ
T1 2cm
T1mic 0.1 cm
T1a > 0.1 to 0.5 cm
T1b > 0.5 to 1 cm
T1c >1 to 2 cm
T2 >2 to 5 cm
T3 > 5 cm
T4 Chest wall/skin
T4a Chest wall
T4b Skin edema/ulceration, satellite skin nodules
T4c Both 4a and 4b
T4d Inflammatory carcinoma
N1 Movable axillary pN1
N2 Fixed axillary
N3 Internal mammary
pN1a Micrometastases only, # 0.2 cm
pN1b Gross metastases
i 1-3 nodes, >0.2 to < 2 cm
ii 4 nodes/>0.2 to < 2 cm
iii through capsule/ < 2 cm
iv 2 cm

Collaborative Stage Elements

For more details on Collaborative Stage, see the Intro to Collaborative Staging module.