This study was designed to address whether simultaneous primary chemo-hormonal therapy provides additional activity compared with chemotherapy alone in breast cancer patients with operable or locally advanced disease. Between January 1997 and January 2002, 211 consecutive patients with T2–4, N0–1, M0 breast cancer were randomized to receive either epirubicin alone (EPI) or epirubicin plus tamoxifen (EPI-TAM). Ki67 expression was evaluated immunohistochemically in tumor specimens obtained before chemotherapy by incision biopsy and at definitive surgery. Tumor shrinkage of >50% was obtained in 76% of patients randomized in the EPI arm and 81.9% of patients randomized in the EPI-TAM arm (not significant). The corresponding rates of clinical and pathological complete response were 20.2 and 21.9% (not significant), and 4.8 and 6.7% (not significant), respectively. Pathologically complete response was more frequently observed in estrogen receptor (ER)-negative (ER−) tumors (P=0.04) and correlated with elevated baseline Ki67 expression (P<0.01). Both EPI and EPI-TAM treatments resulted in a significant reduction in Ki67 expression, either in overall patients (P=0.000) or in patients with ER+ breast cancer (P=0.000). The reduction in Ki67 immunostaining in the EPI-TAM arm was greater than in the EPI arm, leading to a lower Ki67 expression at post-operative residual histology (P=0.0041). The addition of tamoxifen to epirubicin chemotherapy did not improve the response rate but led to a significantly higher reduction in the Ki67 expression. Baseline elevated Ki67 expression and the ER− status were both associated with a greater chance of obtaining a pathological complete response at residual histology.

The purpose of this study is to investigate the role of carbonic anhydrase IX (CAIX) expression in predicting the response to epirubicin and disease-free survival (DFS) in breast cancer patients enrolled in a single institution trial of primary anthracycline and tamoxifen therapy. CAIX expression was assessed in 183 patients with T2–4 N0–1 breast cancer enrolled in a randomized trial comparing four cycles of single agent epirubicin versus epirubicin + tamoxifen as primary systemic treatment. All patients received postoperatively four cycles of the four weekly i.v. cyclophosphamide, methotrexate, 5-fluorouracil regimen. Patients with estrogen receptor (ER)-positive primary tumors received 5 years of adjuvant tamoxifen. Pretreatment, p53 (P = 0.007), c-erbB2 (P < 0.01), and Ki67 (P = 0.02) were directly associated with CAIX expression, while bcl2 (P < 0.000) and ER (P = 0.000) and progesterone receptor (PgR; P < 0.01) were inversely correlated. In multivariate analysis, only high p53 and low bcl2 were independently associated with CAIX positivity. CAIX immunostaining was significantly associated with poor outcome for DFS (P < 0.002) and overall survival (P = 0.001). In multivariate analysis, a significant interaction was found between CAIX and markers of hormone sensitivity, bcl2 (P = 0.01), ER (P = 0.02), PgR (P = 0.02), and lymph node involvement (P = 0.04), in predicting DFS. Presently, there are few clinical markers of resistance to tamoxifen treatment in ER-positive tumors. CAIX expression in breast cancer patients shows a negative predictive role of treatment efficacy in ER-positive patients on the adjuvant tamoxifen after primary chemo-endocrine therapy. Studies investigating the effects of pH on tamoxifen uptake and the effects of therapy with CA inhibitors are planned.