Table 1:

Description of breast cancer staging (16)

StageDescription
Noninvasive
0No evidence of cancer cells or invasion of the basement membrane of the duct or neighbouring normal tissue; includes ductal carcinoma in situ
Invasive
IA

  • Tumour ≤ 2 cm AND

  • No spread outside the breast; no lymph nodes involved

IB

  • No tumour in the breast, but microscopic metastases (> 0.2 mm but ≤ 2 mm) present in axillary lymph nodes OR

  • Tumour present in the breast, ≤ 2 cm, with involvement of lymph nodes

IIA

  • No tumour in the breast, but macroscopic cancer (> 2 mm) in 1–3 axillary lymph nodes OR

  • Tumour ≤ 2 cm, with spread to axillary lymph nodes OR

  • Tumour > 2 cm but ≤ 5 cm, with no spread to axillary lymph nodes

IIB

  • Tumour > 2 cm but ≤ 5 cm, with spread to 1–3 axillary lymph nodes OR

  • Tumour > 5 cm, with no spread to axillary lymph nodes

IIIA

  • No tumour in the breast or presence of a breast tumour of any size associated with metastases in 4–9 axillary lymph nodes or in internal mammary nodes OR

  • Tumour > 5 cm, with spread to axillary and/or internal mammary nodes

IIIB

  • Tumour of any size, with spread to chest wall and/or skin of the breast; may also have spread to axillary or internal mammary nodes

IIIC

  • Tumour of any size, with spread to ≥ 10 axillary lymph nodes OR

  • Spread to lymph nodes above or below the collarbone (supraclavicular nodes) OR

  • Spread to both axillary lymph nodes and internal mammary nodes

Metastatic
IVSpread of cancer to other parts of the body such as liver, lung or bone