Pathological parameters useful in predicting prognosis for patients with breast cancer.

The pathologist has critically important responsibilities as a consultant in the management of patients with breast cancer. The clinical evaluation of the anatomic extent of cancer before treatment, the clinical-diagnostic stage, crudely estimates whether the cancer is localized to the breast, or whether there are regional or distant metastases. The pathologist establishes the diagnosis of cancer microscopically in a biopsy and reports the significant characteristics which can be used in the selection of therapy. The pathologist's additional gross and microscopic examinations after mastectomy, which more precisely document the anatomic extent of the cancer, are the basis of the postsurgical treatment-pathologic stage and provide additional information used to estimate prognosis and determine whether adjunctive therapy is needed. The pathology information used in staging includes the tumor size, histologic type, histologic grade, and presence or absence of axillary of other metastases. These and other pathological factors of significance which are discussed include the gross contour of the tumor as well as the presence or absence of necrosis, and any of the spectrum of cancers that we categorize as "minimal breast cancer" (in situ lobular carcinoma, intraductal carcinoma, invasive carcinoma smaller than 0.5 cm). Furthermore, the prognostic implications of the various histologic types are considered, as well as histologic and cytologic differentiation (grade), multicentricity, vascular invasion, cellular infiltration, and various other factors such as mucin or lipid production, steroid hormone receptors, and the nature of the tumor bed. The presence or absence of axillary lymph node metastases remains the single most significant variable in estimating prognosis for most breast cancers. In addition, combinations of the parameters noted above may have greater prognostic significance than any considered individually. Therefore, the pathologist, through the routine examination and documentation of breast biopsies and mastectomies, can provide important information which can be used to aid in the selection of treatment and in the estimation of prognosis.