Anatomy and Breast Cancer Staging

American Joint Committee on Cancer’s Staging System for Breast Cancer, Eighth Edition: What the Radiologist Needs to Know

“…Anatomic TNM staging may be subdivided into four categories: (a) clinical staging, which is based on the findings from clinical examination, diagnostic imaging, and/or core biopsy specimens; (b) pathologic staging, which is based on surgical specimens (including sentinel lymph node biopsy specimens); (c) posttherapy staging, which is performed after neoadjuvant chemotherapy, radiation therapy, or hormonal therapy, and may include both clinical and pathologic information; and (d) restaging in the event of tumor recurrence (2). Because the purpose of this article is to focus on important concepts for the radiologist, anatomic clinical staging will primarily be discussed.…”

“…Pleomorphic lobular carcinoma in situ is also not distinguished separately, because insufficient data exist with regard to outcomes for this variant of lobular carcinoma in situ. T1 disease is subcategorized as T1mi (tumor size ≤ 1 mm), T1a (tumor size > 1 mm but ≤ 5 mm),T1b (tumor size > 5 mm but ≤ 10 mm), or eighth edition includes two staging systems-the anatomic stage, which includes the size of the primary tumor, nodal status, and distant metastasis; and the prognostic stage, which includes tumor grade, hormone receptor and oncogene expression, and the results of multigene panel testingto accurately predict a patient's outcome (2,3). Prognostic staging is preferred for patient care, but anatomic staging may be used in regions of the world where biomarker testing is not available (4).…”

“…The North American effort to standardize the TNM system for cancer staging was first organized in 1959 as the American Joint Committee for Cancer Staging and End-Results Reporting, which is now the American Joint Committee on Cancer (AJCC). In 1977, the AJCC published the first edition of its cancer staging manual, which would allow physicians to determine appropriate treatment, to evaluate treatment results, and to compare outcomes from various institutions (1,2). The founding editors recognized the need for the staging manual to be periodically revised as new information in the field became available (1).…”

“…Breast MRI is considered optional, with attention given to cases with mammographically occult tumors. Consideration of additional imaging studies, such as bone scintigraphy and CT, is directed by signs or symptoms (2,5).…”

Validation of the 8th edition of the American Joint Committee on Cancer Pathological Prognostic Staging for young breast cancer patients

“…The traditional anatomic tumor (T), node (N), and metastasis (M) staging system was essential for prognostic assessment and treatment decision-making in breast cancer [15]. As the understanding of heterogeneous features in breast cancer has evolved, the lack of biologic information in the traditional American Joint Committee on Cancer (AJCC) anatomic stages has become a limitation in its prognostic assessment [15].…”