# Radiation Oncology/Breast/Staging

* Front Page: Radiation Oncology | RTOG Trials
* Breast: Main Page |
* Staging |
* Breast Overview |
* Prevention |
* Benign |
* DCIS |
* LCIS |
* Paget's |
* Phyllodes tumor |
* Early stage |
* Advanced stage |
* Post mastectomy |
* Inflammatory |
* Partial breast irradiation |
* Regional lymphatics |
* Hormonal therapy |
* Chemotherapy |
* RT technique |
* Recurrence |
* Toxicity of RT |
* Randomized |
* NSABP trials

## Current staging

AJCC 7th Edition (2009)
Primary Tumor:
* T0 - no primary tumor found
* Tis - in situ (DCIS or LCIS or Paget's)
* T1 ≤ 2 cm
** T1mi ≤ 0.1 cm (microinvasive)
** 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 (not including pectoralis muscle)
** T4b Skin edema (peau d'orange), ulceration, or satellite skin nodules
** T4c Both 4a and 4b
** T4d Inflammatory carcinoma
Regional Lymph Nodes :
| Clinical staging | Clinical staging | Pathologic staging | Pathologic staging |
| cN0 | No lymph node metastases | pN0 | No lymph node metastases |
| cN1 | Movable ipsilateral axillary lymph nodes | pN1mi | Micrometastases (> 0.2mm and/or more than 200 cells, but <= 2.0 mm) |
| | | pN1a | 1-3 axillary lymph nodes (at least 1 > 2.0mm) |
| | | pN1b | Metastases in IM nodes (micrometastases, or macrometastases detected by SLN biopsy but not clinically detected) |
| | | pN1c | 1-3 axillary lymph nodes and metastases in IM nodes (micrometastases, or macromets detected by SLN but not clinically detected) |
| cN2a | Ipsilateral axillary lymph nodes fixed or matted | pN2a | 4-9 axillary lymph nodes (at least 1 > 2.0 mm) |
| cN2b | Clinically detected internal mammary nodes in the absence of axillary lymph node metastases | pN2b | Metastases in clinically detected IM nodes in the absence of axillary lymph nodes |
| cN3a | Infraclavicular lymph nodes (level III) | pN3a | 10 or more axillary lymph nodes (at least 1 > 2.0 mm); or infraclavicular (level III) lymph nodes |
| cN3b | Clinically apparent internal mammary nodes with axillary lymph node involvement | pN3b | Metastases in clinically detected IM nodes in the presence of positive axillary nodes; or microscopic IM nodes and more than 3 axillary lymph nodes |
| cN3c | Supraclavicular lymph nodes | pN3c | Supraclavicular lymph nodes |
Mnemonics: "A" Nodes are "A"xillary, "B" Nodes are internal "B"reast (eg IMNs), "C" Nodes are supra"C"lavicular - excludes N1 subgroups
Note: For node counting, at least 1 LN must contain a tumor deposit > 2mm and all remaining quantified nodes must contain tumor deposits > 0.2 mm (at least micromets). Nodes containing only tumor deposits <= 0.2mm (ITCs) are excluded from the positive node count (but should be recorded as additional ITC involved nodes)
Distant Metastases:
* M0 - none
* cM0(i+) - no clinical or radiographic evidence of distant metastases, but tumor cells detected in circulating blood, bone marrow, or other tissues (e.g. prophylactically removed ovaries), ≤ 0.2 mm, in a patient without symptoms or signs of metastases.
* M1 - distant detectable metastases; or histologically proven > 0.2 mm
Stage Grouping:
* 0: Tis
* IA: T1 N0
* IB: T0-T1 N1mi
* IIA: T0-1 N1 or T2 N0
* IIB: T2 N1 or T3 N0
* IIIA: T3 N1 or T0-3 N2
* IIIB: T4 N0-2
* IIIC: N3
* IV: M1
Changes from 6th edition:
* T1mic changed to T1mi to indicate microscopic disease
* Clarification of wording of "not clinically detected" and "clinically detected" internal mammary nodes. *Clarification of Isolated tumor cells (ITC).
* Subdivision of Stage I into IA and IB (IB includes T0-T1 with N1mi nodal micrometastases). Otherwise, no changes in TNM or Overall Stage
* New cM0(i+) category for circulating tumor cells or incidentally discovered metastatic cells in other tissue
* Clarification of assigning staging after neoadjuvant therapy (yc or ypTNM)

### 8th Edition

AJCC 8th edition (2017)
* To be used for staging beginning Jan 1, 2018.
* The prognostic stage group is preferred for patient care, is to be used for reporting of all cancer patients. The anatomic stage group is provided so that stage can be assigned when biomarkers cannot be routinely obtained.
* LCIS is no longer included as in situ
Primary Tumor:
* T0 - no primary tumor found
* Tis (DCIS)
** Note: LCIS is no longer included (benign)
* Tis (Paget)
* T1 ≤ 2 cm
** T1mi ≤ 0.1 cm (microinvasive)
** T1a > 0.1 but ≤ 0.5 cm (round any measurement from >1.0-1.9 mm to 2 mm)
** T1b > 0.5 but ≤ 1 cm
** T1c > 1 but ≤ 2 cm
* T2 > 2 but ≤ 5 cm
* T3 > 5 cm
* T4 Chest wall /skin
** T4a Chest wall (not including pectoralis muscle)
** T4b Skin edema (peau d'orange), ulceration, or satellite skin nodules (satellite tumor nodules in the skin must be evident grossly. Those identified only microscopically do not constitute T4b)
** T4c Both 4a and 4b
** T4d Inflammatory carcinoma
Regional Lymph Nodes :
| Clinical staging | Clinical staging | Pathologic staging | Pathologic staging |
| cN0 | No lymph node metastases | pN0 | No lymph node metastases |
| | | pN0(i+) | ITCs only (malignant cell clusters no larger than 0.2 mm) in regional lymph nodes |
| | | pN0(mol+) | Positive molecular findings by RT-PCR; no ITCs detected |
| cN1 | Metastases to movable ipsilateral level I and II axillary lymph node(s) | pN1mi | Micrometastases (approx 200 cells, larger than 0.2 mm, but none larger than 2.0 mm) |
| cN1mi | Micrometastases (approx 200 cells, larger than 0.2 mm, but none larger than 2.0 mm) | pN1a | Met to 1-3 axillary lymph nodes (at least 1 > 2.0mm) |
| | | pN1b | Met to ipsilateral internal mammary sentinel LNs (excluding ITCs) |
| | | pN1c | pN1a and pN1b combined |
| cN2a | Met in ipsilateral level I and II axillary lymph nodes fixed to one another (matted) or to other structures | pN2a | Met to 4-9 axillary lymph nodes (at least 1 > 2.0 mm) |
| cN2b | Met only in ipsilateral internal mammary LNs in the absence of axillary LN mets | pN2b | Met in clinically detected IM nodes (with/without microscopic confirmation) with pathologically negative axillary lymph nodes |
| cN3a | Met in ipsilateral infraclavicular lymph nodes (level III) | pN3a | Met in 10 or more axillary lymph nodes (at least 1 > 2.0 mm); or met to infraclavicular (level III) lymph nodes |
| cN3b | Met in ipsilateral internal mammary LNs and axillary LNs | pN3b | pN1a or pN2a in the presence of positive internal mammary LNs by imaging; or pN2a in the presence of pN1b (IM sentinel LN) |
| cN3c | Supraclavicular lymph nodes | pN3c | Supraclavicular lymph nodes |
| For cN, use (sn) suffix to denote confirmation of metastases by sentinel LN biopsy; use (f) suffix to denote confirmation by FNA or core needle biopsy. cN1mi for pts who undergo SLN biopsy before tumor resection (i.e. neoadjuvant therapy) | For cN, use (sn) suffix to denote confirmation of metastases by sentinel LN biopsy; use (f) suffix to denote confirmation by FNA or core needle biopsy. cN1mi for pts who undergo SLN biopsy before tumor resection (i.e. neoadjuvant therapy) | For pN, use (sn) and (f) suffixes if confirmed by SLN biopsy or FNA/core biopsy with no further resection of LNs | For pN, use (sn) and (f) suffixes if confirmed by SLN biopsy or FNA/core biopsy with no further resection of LNs |
Distant Metastases:
* M0 - none
* cM0(i+) - no clinical or radiographic evidence of distant metastases, but tumor cells detected in circulating blood, bone marrow, or other tissues (e.g. prophylactically removed ovaries), ≤ 0.2 mm, in a patient without symptoms or signs of metastases.
* M1 - distant detectable metastases; or histologically proven met > 0.2 mm (pM1)
Prognostic Stage Grouping:
Anatomic Stage Grouping:
* 0: Tis
* IA: T1 N0
* IB: T0-T1 N1mi
* IIA: T0-1 N1 or T2 N0
* IIB: T2 N1 or T3 N0
* IIIA: T3 N1 or T1-3 N2
* IIIB: T4 N0-2
* IIIC: N3
* IV: M1
Source:

### Older staging versions

AJCC 6th edition (2002)
Primary Tumor:
* T0 - no primary tumor found
* Tis - in situ (DCIS or LCIS or Paget's)
* T1 ≤ 2 cm
** T1mic ≤ 0.1 cm (microinvasive)
** 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 (not including pectoralis muscle)
** T4b Skin edema (peau d'orange), ulceration, or satellite skin nodules
** T4c Both 4a and 4b
** T4d Inflammatory carcinoma
Lymph nodes :
| Clinical staging | Clinical staging | Pathologic staging | Pathologic staging |
| cN0 | No lymph node metastases | pN0 | No lymph node metastases |
| cN1 | Movable ipsilateral axillary lymph nodes | pN1mi | Micrometastases (> 0.2mm but <= 2.0 mm) |
| | | pN1a | 1-3 axillary lymph nodes |
| | | pN1b | Microscopic involvement of IM nodes (not clinically apparent) but no axillary nodes |
| | | pN1c | 1-3 axillary lymph nodes and microscopic involvement of IM nodes |
| cN2a | Ipsilateral axillary lymph nodes fixed or matted | pN2a | 4-9 axillary lymph nodes |
| cN2b | Clinically apparent internal mammary nodes in the absence of axillary lymph node metastases | pN2b | Clinically apparent IM nodes in the absence of axillary lymph nodes |
| cN3a | Infraclavicular lymph nodes | pN3a | 10 or more axillary lymph nodes; or infraclavicular lymph nodes |
| cN3b | Clinically apparent internal mammary nodes with axillary lymph node involvement | pN3b | Clinically apparent IM nodes in the presence of positive axillary nodes; or microscopic IM nodes and more than 3 axillary lymph nodes |
| cN3c | Supraclavicular lymph nodes | pN3c | Supraclavicular lymph nodes |
Mnemonics: "A" Nodes are "A"xillary, "B" Nodes are internal "B"reast (eg IMNs), "C" Nodes are supra"C"lavicular - excludes N1 subgroups
Nodes:
* Isolated tumor cells (ITC) - small clusters of cells <= 0.2 mm (and < 200 cells), usually with no histologic evidence of malignant activity (such as proliferation or stromal reaction). Designated pN0. If IHC or PCR is performed, may be designated pN0(i+),pN0(i-),pN0(mol+),or pN0(mol-).
* Micrometastases (pN1mi) - > 0.2mm but <= 2.0 mm. May also be designated pN1mi(i+) or pN1mi(i-) if IHC is performed.
Distant metastasis:
* M0 No
* M1 Yes
Stage grouping:
* Stage 0: Tis
* Stage I: T1,N0,M0
* Stage IIA: T0-1,N1,M0 or T2,N0,M0
* Stage IIB: T2,N1,M0 or T3,N0,M0
* Stage IIIA: T3,N1,M0 or T0-3,N2,M0
* Stage IIIB: T4,any N,M0
* Stage IIIC: any T,N3,M0
* Stage IV: any T,any N,M1
AJCC 5th Edition (1997)
* pN1a - micrometastases (<0.2 cm)
* pN1bi - 1-3 nodes, < 2 cm
* pN1bii - 4+ nodes, < 2 cm
* pN1biii - extracapsular extension, < 2 cm
* pN1biv - > 2 cm
Otherwise unchanged compared to 6th edition

## New Classifications

    For additional information, see Tissue microarrays (Breast/Breast overview)
Gene expression profiling is the basis for additional classification schemes.
* Luminal A type - ER+ and/or PR+, HER2–. Usually low grade. These express genes similar to normal cells lining breast ducts and glands
* Luminal B type - ER+ and/or PR+, HER2+. These are similar to luminal A, but grow faster and have a slightly poorer prognosis.
* Basal type - ER–, PR–, HER2–, cytokeratin 5/6 positive, and/or HER1+. Also known as "triple negative". Higher prevalence in young African American women.
* HER2 type - ER-, PR-, HER2+. Usually high histological grade.