COMPARISON BETWEEN KI-67 INDEX AND S-PHASE FRACTION ON FINE-NEEDLE ASPIRATION SAMPLES FROM BREAST-CARCINOMA

BACKGROUND. Fine-needle aspiration (FNA) biopsy has been used increasi ngly in the diagnosis and biologic characterization of breast carcinom as in patients who receive preoperative chemotherapy. Because prolifer ative activity of breast carcinoma has been shown to be of prognostic significance, the authors compared immunocytochemical Ki-67 growth fra ction and now cytometric S-phase fraction (SPF), both evaluated on FNA samples. METHODS, The proliferative activity of 134 FNA samples from primary breast carcinoma patients was studied using both immunocytoche mistry with the monoclonal antibody Ki-67 and SPF determined by DNA fl ow cytometry. RESULTS, Ki-67 and SPF were evaluable in 114 and 107 cas es, respectively, and both were evaluable in 95 cases. Of the 134 FNA samples studied, 37% were diploid and 63% were aneuploid. The distribu tion of both Ki-67 and SPF was different in diploid and aneuploid tumo rs. The median Ki-67 value as well as the median SPF were significantl y higher in aneuploid versus diploid tumors (P < 0.001). Median Ki-67 and SPF Values were used to discriminate between low versus high proli ferating tumors. The overall concordance between Ki-67 and SPF was 75% (P < 0.001). A good correlation was found between Ki-67 and SPF (corr elation coefficient = 0.72; P < 0.001). CONCLUSIONS, The results of th e current study suggest that Ki-67 growth fraction and SPF determined by FNA may be used as measurements of the proliferative activity of br east carcinoma. The authors recommend these determinations be used as preoperative procedures in patients with a cytologic diagnosis of brea st carcinoma who are candidates for neoadjuvant chemotherapy and/or en docrine therapy. (C) 1997 American Cancer Society.