Staging of breast cancer

Staging of breast cancer

TNM definition

Primary tumor (T)

TX: Primary tumor cannot be assessed

T0: No evidence of primary tumor

Tis: Intraductal carcinoma, lobular carcinoma in situ, or Paget’s disease of the nipple with no associated invasion of normal breast tissue

Tis (DCIS): Ductal carcinoma in situ

Tis (LCIS): Lobular carcinoma in situ

Tis (Paget's): Paget's disease of the nipple with no tumor. [Note: Paget's disease associated with a tumor is classified according to the size of the tumor.]

T1: Tumor 2.0 cm or less in greatest dimension

T1mic: Microinvasion 0.1 cm or less in greatest dimension

T1a: Tumor more than 0.1 but not more than 0.5 cm in greatest dimension

T1b: Tumor more than 0.5 cm but not more than 1.0 cm in greatest dimension

T1c: Tumor more than 1.0 cm but not more than 2.0 cm in greatest dimension

T2: Tumor more than 2.0 cm but not more than 5.0 cm in greatest dimension

T3: Tumor more than 5.0 cm in greatest dimension

T4: Tumor of any size with direct extension to (a) chest wall or (b) skin, only as described below.

T4a: Extension to chest wall, not including pectoralis muscle

T4b: Edema (including peau d’orange) or ulceration of the skin of the breast, or satellite skin nodules confined to the same breast

T4c: Both T4a and T4b

T4d: Inflammatory carcinoma.

Memory Aid for Primary tumor: The two numbers to remember are 2.0 and 5.0

T1 < 2.0 cm

T2 2.0 - 5.0 cm

T3 > 5.0 cm

Regional lymph nodes (N)

NX: Regional lymph nodes cannot be assessed (e.g., previously removed)

N0: No regional lymph node metastasis

N1: Metastasis to movable ipsilateral axillary lymph node(s)

N2: Metastasis to ipsilateral axillary lymph node(s) fixed or matted, or in clinically apparent* ipsilateral internal mammary notes in the absence of clinically evident lymph node metastasis

N2a: Metastasis in ipsilateral axillary lymph nodes fixed to one another (matted) or to other structures

N2b: Metastasis only in clinically apparent* ipsilateral internal mammary nodes and in the absence of clinically evident axillary lymph node metastasis

N3: Metastasis in ipsilateral infraclavicular lymph node(s) with or without axillary lymph node involvement, or in clinically apparent* ipsilateral internal mammary lymph node(s) and in the presence of clinically evident axillary lymph node metastasis; or metastasis in ipsilateral supraclavicular lymph node(s) with or without axillary or internal mammary lymph node involvement

N3a: Metastasis in ipsilateral infraclavicular lymph node(s)

N3b: Metastasis in ipsilateral internal mammary lymph node(s) and axillary lymph node(s)

N3c: Metastasis in ipsilateral supraclavicular lymph node(s)

* [Note: Clinically apparent is defined as detected by imaging studies (excluding lymphoscintigraphy) or by clinical examination or grossly visible pathologically.]

Distant metastasis (M)

MX: Presence of distant metastasis cannot be assessed

M0: No distant metastasis

M1: Distant metastasis

Stage grouping

Stage grouping is the process by which each case is classified into its corresponding stage. There are five stages (Stages 0-IV). A patient's stage depends on the extent of his primary tumor (T), regional lymph nodes (N) and whether he/she has metastasis (M) or not.

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Stage 0

Tis, N0, M0

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Stage I

T1, N0, M0

Memory Aid:

T1 corresponds to Stage I

T2 corresponds to Stage IIA or add N1 to previous stage (i.e. T1,N1)

T3 corresponds to Stage IIB or add N1 to previous stage (i.e. T2, N1)

N2 corresponds to Stage IIIA

T4 corresponds to Stage IIIB

N3 corresponds to Stage IIIC

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Stage IIA

T2, N0, M0
T1, N1, M0
T0, N1, M0

Memory Aid:

T1 corresponds to Stage I

T2 corresponds to Stage IIA or add N1 to previous stage (i.e. T1,N1)

T3 corresponds to Stage IIB or add N1 to previous stage (i.e. T2, N1)

N2 corresponds to Stage IIIA

T4 corresponds to Stage IIIB

N3 corresponds to Stage IIIC

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Stage IIB

T3, N0, M0
T2, N1, M0

Memory Aid:

T1 corresponds to Stage I

T2 corresponds to Stage IIA or add N1 to previous stage (i.e. T1,N1)

T3 corresponds to Stage IIB or add N1 to previous stage (i.e. T2, N1)

N2 corresponds to Stage IIIA

T4 corresponds to Stage IIIB

N3 corresponds to Stage IIIC

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Stage III

Memory Aid:

T1 corresponds to Stage I

T2 corresponds to Stage IIA or add N1 to previous stage (i.e. T1,N1)

T3 corresponds to Stage IIB or add N1 to previous stage (i.e. T2, N1)

N2 corresponds to Stage IIIA

T4 corresponds to Stage IIIB

N3 corresponds to Stage IIIC

Stage IIIA

T0, N2, M0
T1, N2, M0
T2, N2, M0
T3, N1, M0
T3, N2, M0

Stage IIIB

T4, Any N, M0

Stage IIIC

Any T, N3, M0

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Stage IV

Any T, Any N, M1

References

1. Breast. In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 171-180.