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Breast

General

Staging

Authors: Emily S. Reisenbichler, M.D., Debra L. Zynger, M.D.

Last author update: 31 March 2022

Last staff update: 13 October 2023

Copyright: 2002-2024, PathologyOutlines.com, Inc.

PubMed Search: Staging[title] breast carcinoma[title]

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Table of Contents

Cite this page: Reisenbichler ES, Zynger D. Staging. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastmalignantstaging.html. Accessed May 6th, 2024.

Definition / general

All carcinomas of the breast are covered by this staging system
Breast sarcomas, phyllodes tumor and breast lymphomas are not staged using this system

Essential features

AJCC 7th edition staging was sunset on December 31, 2017; as of January 1, 2018, use of the 8th edition is mandatory

ICD coding

ICD-10:
- C50.0 - nipple
- C50.1 - central portion of breast
- C50.2 - upper inner quadrant
- C50.3 - lower inner quadrant
- C50.4 - upper outer quadrant
- C50.5 - lower outer quadrant
- C50.6 - axillary tail
- C50.8 - overlapping lesion of breast
- C50.9 - breast, not otherwise specified

Primary tumor (pT)

pTX: cannot be assessed
pT0: no evidence of primary tumor
pTis: ductal carcinoma in situ, Padget disease, encapsulated papillary carcinoma and solid papillary carcinoma
- pTis (DCIS): ductal carcinoma in situ without invasive carcinoma
- pTis (Paget): Paget disease without invasive carcinoma
pT1mi: tumor ≤ 1 mm
pT1a: tumor > 1 mm but ≤ 5 mm
pT1b: tumor > 5 mm but ≤ 10 mm
pT1c: tumor > 10 mm but ≤ 20 mm
pT2: tumor > 20 mm but ≤ 50 mm
pT3: tumor > 50 mm
pT4a: extension to chest wall (not including pectoralis muscle)
pT4b: edema (including peau d'orange), ulceration of skin or ipsilateral satellite skin nodules
pT4c: both T4a and T4b
pT4d: inflammatory carcinoma (involves > 1/3 of the breast skin, primarily a clinical diagnosis)

Notes:

Lobular carcinoma in situ (LCIS) is no longer classified as Tis and is now considered a risk factor, not a malignancy
For invasive tumors, do not include in situ tumor in the tumor measurement used to determine pT category
Round invasive tumor size to the nearest millimeter, except if between 1.0 and 1.4 mm, then round up to 2.0 mm to avoid classifying as pT1mi
Do not add tumor dimensions from the needle biopsy to the excision; use the maximum dimension in either the needle biopsy or excision for pT categorization (invasive tumor is larger in the needle biopsy than subsequent excision in 12% of cases, Am J Surg Pathol 2013;37:739)
If multiple excisions, may want to report "at least pT_, a more accurate estimate may be based on imaging studies"
If there are multiple simultaneous, macroscopically measurable, ipsilateral invasive tumors that are grossly and histologically not connected, use largest individual size, do not sum sizes; can use (m) suffix, e.g., pT1b(m)
Contiguous tumor within the pectoralis muscle should be included in the tumor measurement to determine pT category
In a postneoadjuvant specimen, measure the largest single contiguous focus; do not include the fibrous tumor bed without viable tumor

Regional lymph nodes (pN)

pNX: cannot be assessed
pN0: no regional lymph node metastasis histologically
pN0(i-): no regional lymph node metastasis by histology or immunohistochemistry
pN0(i+): isolated tumor cells (cluster ≤ 0.2 mm and < 200 cells)
pN0(mol+): RT-PCR positive but negative by light microscopy
pN1mi: micrometastasis (tumor deposit > 0.2 mm and ≤ 2.0 mm or ≤ 0.2 mm and > 200 cells)
pN1a: metastasis in 1 - 3 axillary lymph nodes with at least 1 tumor deposit > 2.0 mm
pN1b: metastasis in internal mammary sentinel lymph node with tumor deposit > 2.0 mm
pN1c: pN1a and pN1b
pN2a: metastasis in 4 - 9 axillary lymph nodes with at least 1 tumor deposit > 2.0 mm
pN2b: metastasis in clinically detected internal mammary nodes with pathologically negative axillary nodes
pN3a: metastasis in ≥ 10 axillary lymph nodes with at least 1 tumor deposit > 2.0 mm or metastasis to infraclavicular lymph node
pN3b: positive internal mammary node by imaging with pN1a or pN1b
pN3c: metastasis in ipsilateral supraclavicular lymph node

Notes:

Lymph nodes, including sentinel lymph nodes, should be bisected along the long axis, not serially sectioned along the short axis; if the bisected halves are thick enough (> 2 mm), they should be further longitudinally sectioned (CAP: Cancer Protocol Templates [Accessed 31 March 2022], Mod Pathol 2010;23 Suppl 2:S26, APMIS 2011;119:868)
Regional lymph nodes include axillary, internal mammary, supraclavicular and intramammary
Isolated tumor cells = cluster ≤ 0.2 mm and < 200 cells
Micrometastasis = deposit > 0.2 mm and ≤ 2.0 mm or ≤ 0.2 mm and > 200 cells
Macrometastasis = deposit > 2.0 mm
Count cells or measure tumor within a single lymph node cross section
Measure only the largest contiguous focus of metastatic tumor cells; adjacent satellites are not included
Extranodal extension should be included in the tumor deposit measurement
The number of nodes with isolated tumor cells does not change pN category (e.g., 3 nodes with macrometastases plus 1 node with isolated tumor cells is pN1a, not pN2a)
Direct extension of tumor into an intramammary lymph node is included as a positive regional lymph node
Rounded tumor nodules without nodal tissue present in a nodal drainage area should be considered lymph nodes completely replaced with tumor, unless a vascular wall is present
"Clinically detected" is defined as detected by imaging studies (excluding lymphoscintigraphy) or by clinical examination and having characteristics highly suspicious for malignancy or a presumed pathologic macrometastasis based on fine needle aspiration biopsy with cytologic examination
In a postneoadjuvant node, measure only the largest contiguous metastatic deposit; do not add separate tumor deposits or include fibrosis without viable tumor

Distant metastasis (M)

pM1: distant metastasis histologically proven > 0.2 mm

Prefixes

y: preoperative radiotherapy or chemotherapy
r: recurrent tumor stage

AJCC prognostic stage groups

pTNM, tumor grade, ER, PR and HER2 status are incorporated into prognostic stage groups to refine prognosis
Refer to the AJCC 8th edition for the stage group definitions

Registry data collection variables

ER
PR
HER2 immunohistochemistry
HER2 FISH
HER2 overall
Grade
Ki67
Oncotype DX recurrence score
Oncotype DX DCIS recurrence score
MammaPrint score
PAM50 subtype and score
Breast Cancer Index score
EndoPredict score
IHC4 score
Urokinase plasminogen activator and plasminogen activator inhibitor type (Biomark Insights 2016;11:105)
Response to treatment

Histologic grade (G)

GX: cannot be assessed
G1: low grade (score 3 - 5)
G2: intermediate grade (score 6 - 7)
G3: high grade (score 8 - 9)

Notes:

To assign a histologic grade, assess and combine values for tubule formation (1 - 3), nuclear pleomorphism (1 - 3) and mitotic count (1 - 3) into a score

Histopathologic type