Histologic and staging classification of breast cancer: implications for therapy.
Breast cancer has 20 different histologic descriptions grouped into four categories, A, B, C, and D, based on prognosis. An analysis of 3,902 patients has revealed significant differences in outcome. Class A disease--for the most part in situ--was relatively benign, with a frequency distribution of 5%. Positive nodes were found in 1.6%, and five-year survival curves exceeded 91%. Class B (mucinous, medullary, etc) occurred in 4.1% of patients. Fewer advanced stages indicated less aggressive tumors, and survival at five years was 75%. The most common class, C (85%), had a five-year survival of 66%, closely related to stage. Class D tumors, 4.3% with ill defined, wildly infiltrative borders, and undifferentiation, were ominous with 33% demonstrating distant spread at first diagnosis. The five-year survival was only 46%. Epidemiologic findings revealed a high incidence of bilaterality and high family risk in some categories, but not in others. Mammography should be done in all class A lesions. A complete pretreatment metastatic survey is recommended for class D patients, as well as those with advanced stage II and III lesions. Indications for various surgical and adjuvant therapies are described.