Stage is directly related to prognosis and determines the type of treatment to be offered, especially when several therapies are available. The TNM classification system is used to stage breast cancer according to the size of the primary tumor (T), the involvement of the lymph nodes in the armpit (axillary nodes) next to the affected breast (N) and the presence or absence of metastases (M). The clinical stages range from Stage I to IV. Stage 0 is in situ cancer, which is still localized to the point of origin and has not yet begun to invade surrounding tissues. TNM staging for breast cancer is ( shown on PAGE 30 to 42 ).
