Breast cancer staging
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Breast cancer staging On the Web |
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American Roentgen Ray Society Images of Breast cancer staging |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor in Chief(s): Soroush Seifirad, M.D.[2], Jack Khuri
Overview
Breast cancer used to be staged according to the TNM system. Recently, the American Joint Committee on Cancer (AJCC) Staging Manual (8th edition, last updated 1/25/2018) extensively revised their staging system. The 8th edition of the AJCC TNM breast cancer staging system delivers a flexible platform for prognostic classification based on traditional anatomic factors, which may be modified and enhanced with respect to patient biomarkers and other prognostic panel data. Nevertheless, in order to maintain worldwide value, AJCC tumor staging system remained based on classic TNM anatomic factors. Prognosis is closely linked to results of staging, and staging is also used to allocate patients to treatments both in clinical trials and clinical practice.
Staging
- The 8th edition of the AJCC TNM breast cancer staging system delivers a flexible platform for prognostic classification based on traditional anatomic factors, which may be modified and enhanced with respect to patient biomarkers and other prognostic panel data.[1]
- Nevertheless, in order to maintain worldwide value, AJCC tumor staging system remained based on classic TNM anatomic factors.
- Major changes in the 8th edition of AJCC TNM staging system were discussed below.
- AJCC panel incorporated biologic factors into the staging system as follows:
- Tumor grade
- Proliferation rate
- Estrogen and progesterone receptor expression
- Human epidermal growth factor 2 (HER2) expression
- Gene expression prognostic panels
- Hence components of recent breast cancer staging system are as follows:
- The extent (size) of the tumor (T)
- The spread to nearby lymph nodes (N)
- The spread (metastasis) to distant sites (M)
- Estrogen receptor (ER) presence
- Progesterone receptor (PR) presence
- Her2/neu (HER2) presence
- Histopathologic grade of the cancer (G):
- In certain circumstances, gene expression panels might also be used such as The Oncotype DX® and the MammaPrint® .
Gene expression panels
- Oncotype DX®:
- For small hormone receptor-positive tumors that have not spread to more than 3 lymph nodes
- Also may be used for more advanced tumors
- Might be used for DCIS (ductal carcinoma in situ or stage 0 breast cancer). as well looks at a set of 21 genes in tumor biopsy samples to get a “recurrence score,” which is a number between 0 and 100.
- The score reflects the risk of breast cancer coming back (recurring) in the next 10 years and how likely you will benefit from getting chemo after surgery.
- The lower the score (usually 0-10) the lower the risk of recurrence.
- Benefit from chemotherapy is in doubt in most women with low scores
- An intermediate score (usually 11-25): intermediate risk of recurrence.
- Benefit from chemotherapy is in doubt in most women with intermediate-recurrence scores,
- Nevertheless chemotherapy is believed to be beneficial for women younger than 50 with a higher intermediate score (16-25)
- The possible risks and benefits of chemo should be weighted and discussed prior to decision making.
- A high score (usually 26-100): higher risk of recurrence.Chemotherapy is recommended for women with high scores in order to help lower the chance of cancer *recurrence.
- MammaPrint®:
- To determine likelihood of cancer recurrence in distant part of the body after treatment.
- May be used in any type of breast cancer with stage 1 or 2 that has spread to no more than 3 lymph nodes.
- Hormone and HER2 status are also evaluated in this test. Seventy different genes are examined in this test to determine the 10 years cancer recurrence
- The test results are reported as either “low risk” or “high risk.”
T categories for breast cancer
- TX: Primary tumor cannot be assessed.
- T0: No evidence of primary tumor.
- Tis: Carcinoma in situ (DCIS, or Paget disease of the nipple with no associated tumor mass)
- T1 (includes T1a, T1b, and T1c): Tumor is 2 cm (3/4 of an inch) or less across.
- T2: Tumor is more than 2 cm but not more than 5 cm (2 inches) across.
- T3: Tumor is more than 5 cm across.
- T4 (includes T4a, T4b, T4c, and T4d): Tumor of any size growing into the chest wall or skin. This includes inflammatory breast cancer.
N categories for breast cancer
- NX: Nearby lymph nodes cannot be assessed (for example, if they were removed previously).
- N0: Cancer has not spread to nearby lymph nodes.
- N0(i+): The area of cancer spread contains less than 200 cells and is smaller than 0.2 mm. The abbreviation "i+" means that a small number of cancer cells (called isolated tumor cells) were seen in routine stains or when a special type of staining technique, called immunohistochemistry, was used.
- N0(mol+): Cancer cells cannot be seen in underarm lymph nodes (even using special stains), but traces of cancer cells were detected using a technique called RT-PCR. RT-PCR is a molecular test that can find very small numbers of cancer cells. (This test is not often used to find breast cancer cells in lymph nodes because the results do not influence treatment decisions.)
- N1: Cancer has spread to 1 to 3 axillary (underarm) lymph node(s), and/or tiny amounts of cancer are found in internal mammary lymph nodes (those near the breast bone) on sentinel lymph node biopsy.
- N1mi: Micrometastases (tiny areas of cancer spread) in the lymph nodes under the arm. The areas of cancer spread in the lymph nodes are at least 0.2mm across, but not larger than 2mm.
- N1a: Cancer has spread to 1 to 3 lymph nodes under the arm with at least one area of cancer spread greater than 2 mm across.
- N1b: Cancer has spread to internal mammary lymph nodes on the same side as the cancer, but this spread could only be found on sentinel lymph node biopsy (it did not cause the lymph nodes to become enlarged).
- N1c: Both N1a and N1b apply.
- N2: Cancer has spread to 4 to 9 lymph nodes under the arm, or cancer has enlarged the internal mammary lymph nodes
- N2a: Cancer has spread to 4 to 9 lymph nodes under the arm, with at least one area of cancer spread larger than 2 mm.
- N2b: Cancer has spread to one or more internal mammary lymph nodes, causing them to become enlarged.
- N3: Any of the following:
- N3a: either:
- Cancer has spread to 10 or more axillary lymph nodes, with at least one area of cancer spread greater than 2 mm,
- OR
- Cancer has spread to the lymph nodes under the collarbone (infraclavicular nodes), with at least one area of cancer spread greater than 2 mm.
- N3b: either:
- Cancer is found in at least one axillary lymph node (with at least one area of cancer spread greater than 2 mm) and has enlarged the internal mammary lymph nodes,
- OR
- Cancer has spread to 4 or more axillary lymph nodes (with at least one area of cancer spread greater than 2 mm), and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy.
- N3c: Cancer has spread to the lymph nodes above the collarbone (supraclavicular nodes) with at least one area of cancer spread greater than 2 mm.
M categories for breast cancer
- MX: Distant spread (metastasis) cannot be assessed.
- M0: No distant spread is found on x-rays (or other imaging tests) or by physical exam.
- cM0(i+): Small numbers of cancer cells are found in blood or bone marrow (found only by special tests), or tiny areas of cancer spread (no larger than 0.2 mm) are found in lymph nodes away from the underarm, collarbone, or internal mammary areas.
- M1: Cancer has spread to distant organs (most often to the bones, lungs, brain, or liver).
Breast carcinoma TNM anatomic stage group Adopted from AJCC 8th Edition
- This system is solely recommended for countries with no/limited access to the other mentioned biochemical and genetic tests.
- Stage 0
- Tis N0 M0
- Stage IA
- T1 N0 M0
- Stage IB
- T0 N1mi M0
- T1 N1mi M0
- Stage IIA
- T0 N1 M0
- T1 N1 M0
- T2 N0 M0
- Stage IIB
- T2 N1 M0
- T3 N0 M0
- Stage IIIA
- T0 N2 M0
- T1 N2 M0
- T2 N2 M0
- T3 N1 M0
- T3 N2 M0
- Stage IIIB
- T4 N0 M0
- T4 N1 M0
- T4 N2 M0
- Stage IIIC
- Any T3 N M0
- Stage IV
- AnyT Any N M1
Summary of stages
In a nutshell
In a nutshell, rather than classic TNM staging system, the following biological factors were incorporated into the prognostic staging system of the eighth edition of the AJCC staging manual:
- Estrogen receptor (ER) and progesterone receptor (PR) expression
- Human epidermal growth factor receptor 2 (HER2)
- Histologic grade
- Recurrence Score (RS)
In addition to the above-mentioned factors, the AJCC mentioned several other factors that might help to determine the prognosis in patients with breast cancer, although the followings were not formally included in the current staging system:
- Ki-67 :
- Cellular proliferation and tumor balk marker
- Multigene expression assays other than RS:
- Mammaprint, EndoPredict, PAM50 Risk of Recurrence (ROR), and the Breast Cancer Index (level II evidence)
- Risk assessment models:
- Adjuvant! Online
- PREDICT-Plus
- Circulating tumor cells (CTCs):
- Cancer cells that separate from solid tumors and enter the bloodstream
- The cutoff for an unfavorable prognosis is ≥5 cells/7.5 mL
- Disseminated tumor cells (DTCs):
- Disseminated tumor cells in the bone marrow
- Might predict the likelihood of relapse at the time of initial tumor resection
- The relevant cutoff is ≥1 cell.
References
- ↑ Giuliano AE, Connolly JL, Edge SB, Mittendorf EA, Rugo HS, Solin LJ et al. (2017) Breast Cancer-Major changes in the American Joint Committee on Cancer eighth edition cancer staging manual. CA Cancer J Clin 67 (4):290-303. DOI:10.3322/caac.21393 PMID: 28294295