Result card

  • CUR2: How is the disease/health condition currently being diagnosed? Include a description of any relevant classification system
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How is the disease/health condition currently being diagnosed? Include a description of any relevant classification system

Authors: Sarah Baggaley, Massimo Gion

Internal reviewers: Luciana Ballini, Aurora Llanos, Antonio Migliore, Claudia Wild

The information used for this section was from other HTAs, a government agency website and cancer research charity websites.

The condition is breast cancer. ICD-10 code: C50

Stage of breast cancer

After breast cancer has been diagnosed, various tests are performed to find out if the cancer has spread and to determine the stage of the disease. The stage of the breast cancer can inform decisions on the most appropriate treatment and help predict the prognosis of the patient.

Two systems can be used to describe the stage of the breast cancer, the numerical system {6} and the TNM classification system {7}.

The numerical system describes the cancer stage based on four characteristics {8}:

  • size of the tumour
  • whether the cancer is invasive or non-invasive
  • whether the cancer is in the lymph nodes
  • whether the cancer has spread to other parts of the body beyond the breast

Stage 0

Stage 0 is used to describe non-invasive breast cancers, such as ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). There is no evidence of cancer cells or pre-cancerous cells invading the surrounding healthy breast tissue.

Stage I

Stage I describes invasive breast cancer. There is evidence of cancer cells invading the surrounding healthy breast tissue. Stage I is divided into subcategories known as IA and IB:

  • Stage IA describes invasive breast cancer in which the tumour measures up to 2 cm and the cancer has not spread outside the breast.
  • Stage IB describes invasive breast cancer in which there are small groups of cancer cells (0.2–2 mm) found in the lymph nodes in combination with no breast tumour or a tumour less than 2 cm in size.

Stage II

Stage II is also divided into two subcategories.

  • Stage IIA describes invasive breast cancer in which either:
    • there is no breast tumour but cancer cells are found in the axillary lymph nodes; or
    • there is a breast tumour of 2 cm or smaller and cancer cells are found in the axillary lymph nodes; or
    • there is a breast tumour 2–5 cm in size but there are no cancer cells in the axillary lymph nodes
  • Stage IIB describes invasive breast cancer in which either:
    • there is a breast tumour 2–5 cm in size and cancer cells are found in the axillary lymph nodes; or
    • there is a breast tumour larger than 5 cm but there are no cancer cells in the axillary lymph nodes

Stage III

Stage III is divided into three subcategories.

  • Stage IIIA describes invasive breast cancer in which either:
    • there is no breast tumour but cancer cells are found in the axillary lymph nodes that are attached to each other or other structures, or cancer cells are found in the lymph nodes near the breastbone; or
    • there is a breast tumour (of any size) and cancer cells are found in the axillary lymph nodes that are attached to each other or other structures, or cancer cells are found in the lymph nodes near the breastbone
  • Stage IIIB describes invasive breast cancer in which the tumour can be of any size and cancer:
    • has spread to the chest wall and/or skin of the breast; and
    • may have spread to axillary lymph nodes that are attached to each other or other structures, or cancer cells are found in the lymph nodes near the breastbone

Cancer that has spread to the skin of the breast is inflammatory breast cancer and is considered at least stage IIIB.

  • Stage IIIC describes invasive breast cancer in which there is no breast tumour or, if there is a tumour, it can be of any size and cancer:
    • may have spread to the chest wall and/or the skin of the breast; and
    • the cancer has spread to lymph nodes above or below the collarbone; and
    • the cancer may have spread to axillary lymph nodes or to lymph nodes near the breastbone

Stage IIIC breast cancer is divided into operable and inoperable stage IIIC.

  • Operable stage IIIC describes stage IIIC invasive breast cancer in which either:
    • cancer is found in ten or more axillary lymph nodes; or
    • cancer is found in lymph nodes below the collarbone; or
    • cancer is found in axillary lymph nodes and in lymph nodes near the breastbone
  • Inoperable stage IIIC describes stage IIIC invasive breast cancer in which the cancer has spread to the lymph nodes above the collarbone

Stage IV

Stage IV is used to describe invasive breast cancer that has spread beyond the breast and nearby lymph nodes to other organs of the body, such as the lungs, distant lymph nodes, skin, bones, liver, or brain {6, 8}.

The TNM classification system describes the cancer stage based on three characteristics:

  • size of the tumour (T),
  • whether the cancer is in the lymph nodes (N)
  • whether the cancer has metastasised, or spread to other parts of the body beyond the breast (M)

The T (size) category describes the primary tumour:

  • TX: primary tumour cannot be assessed
  • T0: no evidence of primary tumour
  • Tis: non-invasive breast cancers; DCIS, LCIS
  • T1: tumour is no more than 2 cm across
    • T1mic: cancer cells have spread no more than 0.1 cm into surrounding tissue (microinvasion)
    • T1a: tumour is 0.1–0.5 cm across
    • T1b: tumour is 0.5–1.0 cm across
    • T1c: tumour is 1–2 cm across
  • T2: tumour is 2–5 cm across
  • T3: tumour is more than 5 cm across
  • T4: tumour of any size that has spread into the (a) chest wall or (b) skin
    • T4a: tumour has spread into the chest wall
    • T4b: tumour has spread into the skin
    • T4c: tumour is fixed to both the skin and the chest wall
    • T4d: inflammatory carcinoma. The overlying skin of the cancer is red, swollen and painful to touch

The higher the T number, the larger the tumour and the more it may have grown into the breast tissue.

The N (lymph node involvement) category describes whether or not the cancer has spread to the lymph nodes:

  • NX: lymph nodes cannot be assessed
  • N0: no evidence of cancer cells in lymph nodes
  • N1: cancer cells in the axillary lymph nodes but the nodes are not attached to surrounding tissues
  • N2 is divided into two subcategories:
    • N2a: cancer cells in the axillary lymph nodes that are attached to each other and other structures
    • N2b: no cancer cells in the axillary lymph nodes but cancer cells are present in the lymph nodes near the breastbone.
  • N3 is divided into three subcategories:
    • N3a: cancer cells in lymph nodes below the collarbone
    • N3b: cancer cells in the axillary lymph nodes and the lymph nodes near the breastbone
    • N3c: cancer cells in the lymph nodes above the collarbone

The higher the N number, the greater the extent of the lymph node involvement.

The M (metastasis) category describes whether or not the cancer has spread to other parts of the body:

  • MX: metastasis cannot be assessed
  • M0: no evidence of distant metastasis
  • M: distant metastasis is present {9, 10}

Tumour grade

In addition to the stage of the cancer, another factor that is considered when making treatment decisions is the tumour grade.

The tumour grade describes the appearance of cancer cells when compared with healthy breast cells under the microscope.

Grade 1 (low grade)

Grade 1 is used to describe a tumour in which the cancer cells grow very slowly and appear similar to healthy breast cells.

Grade 2 (moderate or intermediate grade)

Grade 2 is used to describe a tumour in which the cancer cells appear abnormal and are faster growing

Grade 3 (high grade)

Grade 3 is used to describe a tumour in which the cancer cells grow rapidly and appear very different to healthy breast cells

High grade tumours are likely to be metastatic and are treated more aggressively than low grade tumours {11}.

Receptor status

The receptor status of the cancer will also be determined to inform decisions about the most appropriate treatment for the patient and the risk of breast cancer recurrence.

Some breast cancers have receptors for the hormones oestrogen and progesterone. Breast cancers that express high levels of the oestrogen receptor are considered oestrogen receptor-positive (ER+) and those that do not express the receptor are considered oestrogen receptor-negative (ER-). Generally, ER+ cancers are sensitive to treatment with hormone (endocrine) therapies.

Some breast cancers have receptors for the HER2 (human epidermal growth factor 2) protein. Those cancers expressing high levels of the HER2 receptor are considered HER2-positive (HER2+) and are sensitive to treatment with trastuzumab (Herceptin) {12}.

Important
Completely
Baggaley S, Gion M Result Card CUR2 In: Baggaley S, Gion M Health Problem and Current Use of the Technology In: Jefferson T, Vicari N, Raatz H [eds.]. Prognostic tests for breast cancer recurrence (uPA/PAI-1 [FEMTELLE], MammaPrint, Oncotype DX ) [Core HTA], Agenzia nationale per i servizi sanitari regionali (age.na.s), Italy ; 2013. [cited 7 February 2023]. Available from: http://corehta.info/ViewCover.aspx?id=113

References