EFFECTS OF CHEMOTHERAPY ON PATHOLOGICAL AND BIOLOGIC CHARACTERISTICS OF LOCALLY ADVANCED BREAST-CANCER

In 42 patients with locally advanced breast cancer treated with neoadj uvant chemotherapy followed by surgery and radiation therapy, the effe cts of chemotherapy on tumor architecture, morphemetric nuclear and nu cleolar characteristics, DNA ploidy, proliferation index measured by m itotic activity index, expression of differentiation antigens, and mic rovessel density were studied. Pretreatment biopsy specimens were avai lable to compare with mastectomy specimens for 24 patients, and subcla vicular biopsy specimens taken before chemotherapy were available for 9 patients. In the remaining patients, fine-needle aspiration was perf ormed before chemotherapy, and morphologic and biologic features of th e tumors could be studied only after chemotherapy. In 23 patients, onl y microscopic tumor or no tumor was left after chemotherapy, and in th ese patients we observed a characteristic pattern of relatively cellul ar fibrous tissue with lymphocytic infiltrate, iron-loaded macrophages , and, when present, scattered foci of tumor cells in between. We foun d a reduction in mitotic activity index and in global microvessel dens ity over all the tumors as a group. There was, however, no consistent pattern of changes in nuclear and nucleolar morphometric characteristi cs, DNA ploidy, and expression of differentiation antigens, and no pat hologic or biologic features were predictive for response to chemother apy.