Staging of Breast Cancer

The pathologic ("p") stage of breast cancer takes into consideration the characteristics of the tumor ("T") and the presence of any lymph nodes metastases ("N") or distant organ metastases ("M"). The major tumor characteristic that influences the stage is the tumor size; therefore, the final pathologic stage usually cannot be determined on a core needle biopsy specimen, because the tumor may be larger than the size of the small biopsy. Sometimes patients receive radiation or chemotherapy before surgery to remove a breast cancer (this is called "neoadjuvant therapy"); in these cases, the tumor may shrink or disappear by the time of the surgery. This will influence the pathologic stage and can be designated by a little "y", which indicates that the stage has been determined "after treatment."

The American Joint Committee on Cancer published a revised protocol for the examination of specimens from patients with invasive breast cancers in 2009, which is the 7th edition of cancer staging. The following summary lists the features which pathologists use to determine the pathologic stage of disease:

TNM Descriptors (required only if applicable)
m (multiple foci of invasive carcinoma)
r (recurrent)
y (posttreatment)

Primary Tumor (pT)


Regional Lymph Nodes (pN)


Distant Metastasis (M)