The smaller the tumor is, generally the better the prognosis and the lower the T status. Those larger than 5 centimeters are associated with a poorer prognosis. Other factors that contribute to a higher, or worse, T status include extension outside the breast tissue to involve the chest wall or skin. N is an assessment of regional lymph nodes, when they are submitted as part of an axillary node dissection. The best prognosis is associated with no lymph node involvement by metastatic tumor.
Prognosis becomes worse, and stage is increased, when even one lymph node is involved.
The involvement of four or more lymph nodes, while not changing the stage, is associated with an even poorer prognosis than just one to three positive nodes. M involves a clinical assessment for distant metastases. The pathologist's involvement in this area is usually limited to diagnosing biopsy material from a clinically suspected distant site of metastasis. The different histologic types of breast carcinoma have been roughly divided into favorable and unfavorable prognostic types, through the use of follow-up studies. The favorable prognostic types of carcinoma, as a group, are less common and include lobular, papillas, cribriform, medullary, tubular, mucinous, and adenoid cystic carcinoma.