The American Joint Committee on Cancer (AJCC) staging system provides a strategy for grouping patients with respect to prognosis. Therapeutic decisions are formulated in part according to staging categories but primarily according to the following:
Human epidermal growth factor receptor 2 (HER2/neu) status.
General health of the patient.
Definitions of TNM and AJCC Stage Groupings
The AJCC has designated staging by tumor, node, and metastasis (TNM) classification to define breast cancer. When this system was modified in 2002, some nodal categories that were previously considered stage II were reclassified as stage III. As a result of the stage migration phenomenon, survival by stage for case series classified by the new system will appear superior to those using the old system.
a Reprinted with permission from AJCC: Breast. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 347-76.
b The T classification of the primary tumor is the same regardless of whether it is based on clinical or pathologic criteria, or both. Size should be measured to the nearest millimeter. If the tumor size is slightly less than or greater than a cutoff for a given T classification, it is recommended that the size be rounded to the millimeter reading that is closest to the cutoff. For example, a reported size of 1.1 mm is reported as 1 mm, or a size of 2.01 cm is reported as 2.0 cm. Designation should be made with the subscript "c" or "p" modifier to indicate whether the T classification was determined by clinical (physical examination or radiologic) or pathologic measurements, respectively. In general, pathologic determination should take precedence over clinical determination of T size.
c Invasion of the dermis alone does not qualify as T4.
Primary tumor cannot be assessed.
No evidence of primary tumor.
Paget disease of the nipple NOT associated with invasive carcinoma and/or carcinomain situ(DCIS and/or LCIS) in the underlying breast parenchyma. Carcinomas in the breast parenchyma associated with Paget disease are categorized based on the size and characteristics of the parenchymal disease, although the presence of Paget disease should still be noted.
Tumor ≤20 mm in greatest dimension.
Tumor ≤1 mm in greatest dimension.
Tumor >1 mm but ≤5 mm in greatest dimension.
Tumor >5 mm but ≤10 mm in greatest dimension.
Tumor >10 mm but ≤20 mm in greatest dimension.
Tumor >20 mm but ≤50 mm in greatest dimension.
Tumor >50 mm in greatest dimension.
Tumor of any size with direct extension to the chest wall and/or to the skin (ulceration or skin nodules).c
Extension to the chest wall, not including only pectoralis muscle adherence/invasion.
Ulceration and/or ipsilateral satellite nodules and/or edema (including peau d'orange) of the skin, which do not meet the criteria for inflammatory carcinoma.