Predictive factors of response to first-line chemotherapy in 1426 women with metastatic breast cancer

Since response to chemotherapy is a major determinant of survival in metast atic breast cancer, the purpose of our study was to analyse the predictive factors of response. 1426 patients enrolled into eight consecutive randomis ed trials of anthracycline-based first-line chemotherapy in metastatic brea st cancer, between 1977 and 1992, were analysed. A forward stepwise logisti c regression analysis was used. The objective response rate (ORR) to chemot herapy in the total population was 63.6% (95% confidence interval (CI): 61. 5-67.7). The complete response rate was 17.5%. Multivariate analysis define d adjuvant chemotherapy, lactate dehydrogenase (LDH), Karnofsky index (KI), and pleural and lung metastases to be the five main variables correlated w ith ORR. A predictive score was calculated using the coefficient of these f ive variables. The score was established as follows: -1.32+0.54 (if prior a djuvant chemotherapy) + 0.80 (low KI) + 0.75 (raised LDH) + 0.49 (lung meta stases) + 0.51 (pleural metastases). A low score (less than -0.78) was asso ciated with an ORR greater than 70.0%, representing 41.2% of our population . An intermediate score (between -0.78 and 0) was associated with an ORR of 50 to 70%, representing 37.5% of our population and a positive score was a ssociated with an ORR of less than 50%, representing 21.3% of our populatio n. This score can be used to predict objective response rates to first-line anthracycline-based chemotherapy. This method now needs to be evaluated pr ospectively in phase II trials. Identification of various risk groups may a lso be useful for interpretation and design of clinical trials. (C) 2000 El sevier Science Ltd. All rights reserved.