Prediction of response to primary chemotherapy for operable breast cancer

The use of primary systemic cytotoxics leads to a high remission rate in pa tients with breast cancer. Response was identified as an important variable associated with survival. Thus, features which predict response, are poten tially relevant for planning treatments and improving survival. Retrospecti vely, we investigated several histopathological features (expression of oes trogen and progesterone receptors, Mib1, bcl-2, c-erbB-2, and p53) prior to two programmes of either sequential preoperative chemotherapy (doxorubicin plus cyclophosphamide) and radiotherapy (Group A), or preoperative chemoth erapy (5-fluorouracil, folinic acid and vinorelbine) alone (Group B) in pat ients with operable breast cancer. After three courses, patients with a par tial or complete response were given a further three courses, which was fol lowed for patients in Group A by radiotherapy 50 Gy plus a boost of 10 Gy. All patients were submitted to surgery after completion of preoperative tre atment and pathology material from 73 patients (median age, 49 years, range , 30-70; performance status, 0-1; 68 T-2, 5 T-3) was obtained. The overall response rate according to radiological and clinical evaluation was 59% (68 % for Group A and 49% for Group B). 12 of 14 patients with p53-positive tum ours and 31 of 59 with p53-negative tumours responded (P = 0.04). 6 of 7 pa tients with elevated c-erbB-2 had a response compared with 37 of 66 patient s in the group with c-erbB-2 negative tumours (P = 0.03). Mib1 expression d ecreased substantially (greater than or equal to 50%) in 25 patients during treatment, of whom 20 responded compared with 21 of 48 patients with a low er decrease (P = 0.04). Response was observed in 28 of 37 patients with hig h baseline Mib1 (> 20%) and in 15 of 36 patients in the low Mib1 group (P = 0.05). Finally, 32 of 44 tumours with low expression of progesterone recep tors responded compared with 11 of 29 tumours with high receptors expressio n (P = 0.05). These markers might be useful for tailoring primary and posts urgical systemic treatments. (C) 1999 Elsevier Science Ltd. All rights rese rved.