The 1st step in breast cancer treatment is complete diagnostics. If a doctor confirms breast cancer, the establishing breast cancer stage is necessary to develop an effective treatment plan.

The stage of cancer is the degree of malignant tumor development. Determining the stage of the disease is very important for choosing the best treatment option and prognosis.

There are different systems for determining the stages.

Clinical classification of stages

Stage 0

Breast cancer in situ. Malignant cells do not spread to the surrounding tissues and do not go beyond the primary focus.

Stage 1

A tumor is up to 2 cm in size and invades the other organs and tissues.

Stage 2

2A — is cancer stage when a tumor is up to 2 cm with metastases in the underarm lymph nodes or a tumor is up to 2-5 cm without metastases;

2B — is cancer stage when a tumor is up to 2-5 cm with metastases in the underarm lymph nodes or a tumor is 5 cm in size or bigger without metastases.

Stage 3

3A — at this stage a tumor is up to 5 cm with metastases in the underarm and retrosternal lymph nodes;

3B — a tumor may be of any size with metastases in the chest or skin;

3C — a tumor of any size grows with metastases to the underarm, retrosternal and clavicular lymph nodes.

Stage 4

Metastatic breast cancer. The metastases involve the spread to the distant organs, such as the liver, bones, chest cavity, skin, brain, and adrenals.

TNM classification

TNM classification of breast cancer systematizes the size and area of metastases spread to lymph nodes and distant organs:

  • T (Tumor) is a characteristic of the malignant formation size and its spread to the surrounding tissues;
  • N (Nodes) stage means the degree of lymph nodes involvement in the oncological process;
  • M (Metastasis) stage implies the presence and size of distant metastases.

What is T in TNM classification?

Tis means that carcinoma is in situ and does not spread to the surrounding tissues.

  • Tis (DCIS) – ductal carcinoma in situ (affects mammary ducts);
  • Tis (LCIS) – lobular carcinoma in situ (affects lobuli);
  • Tis (Paget) – Paget’s cancer (affects nipples or areola).

T1 — the size of tumor is up to 2 cm;

T2 — the size of tumor is 2-5 cm;

T3 — the size of tumor is up to 5 cm;

T4 — tumor of any size spreading to the chest or skin.

breast cancer stages tnm image

What does N in TNM classification mean?

  • N0 (clinical study) — the tumor has not affected the regional lymph nodes according to the clinical examination;
  • N0 (pathological study) — cancer has not changed the regional lymph nodes according to the results of microscopic examination of tissue;
  • N1 (clinical research) — the tumor grows to the axillary lymph nodes;
  • N1 (pathological study) — cancer grows to 1-3 axillary lymph nodes;
  • N2 (clinical examination) — metastases in the axillary lymph nodes welded together;
  • N2 (pathological review) — the tumor grows to 4-9 axillary lymph nodes;
  • N3 (clinical research) — metastases spread to subclavian lymph nodes, or in the intrathoracic lymph nodes. Metastases may also spread to the supraclavicular lymph nodes, regardless of metastases in the axillary and intrathoracic lymph nodes.

What does M mean in TNM breast cancer classification?

  • M0 - metastases do not spread to distant organs;
  • M1 - metastases affect distant organs.

Treatment of breast cancer depending on stage

Stages 1-2

Methods of 1 and 2 stages breast cancer treatment:

  • lumpectomy is provided when a tumor is up to 2 cm in size;
  • mastectomy is applied in such cases:

- if a patient is pregnant at the time of treatment;

- if several lumps cannot be removed from one incision;

- if there are visual signs of breast cancer throughout the breast;

- if the tumor is over 5 cm.

  • Chemotherapy;
  • radiation therapy;
  • hormonal therapy (if there are hormones receptors).

Stage 3

Methods of 3 stage breast cancer treatment:

  • mastectomy;
  • chemotherapy;
  • hormone therapy;
  • radiation therapy.

Stage 4

Methods of 4 stage breast cancer treatment:

  • chemotherapy;
  • target therapy;
  • hormonal therapy (ablation of the ovaries).