Introducing taxanes in the adjuvant treatment of breast cancer: expectations and reality

Adjuvant chemotherapy in early boast cancer significantly improves disease- free and overall survival. However? a recent update of the world-wide overv iew indicated that improvements, though statistically significant, are of m odest magnitude. Considering the results of individual clinical trials, fur ther improvements in disease-foe survival through introduction of new drugs as part of adjuvant treatment for breast cancer are expected to be small. Phase III studies in advanced, measurable disease, each involving several h undreds of patients, have been conducted with both paclitaxel and docetaxel and these results are now available. The high level of efficacy observed, especially with docetaxel, has led to their prompt introduction into adjuva nt trials, and the results of one trial with paclitaxel are already availab le. In this trial, which included 3170 patients, paclitaxel was given every three weeks for four courses following an adjuvant treatment with four cou rses of doxorubicin and cyclophosphamide (AC) combination. The sequential u se of the BC following by the taxane showed an early significant improvemen t of disease-free survival as compared to AC alone, but the difference obse rved was exclusively in the 40% of patients who had oestrogen receptor (OR) -negative disease. These patients, and a few of those with OR-positive prim aries, did not receive tamoxifen following chemotherapy. Differences in dur ation of the entire adjuvant treatment programme might have influenced resu lts leading to potentially the wrong conclusion being drawn that the taxane made the difference and other treatment variables had a negligible influen ce on outcome. Taxanes deserve a 'fair trial' in the adjuvant setting. More over, potential cardiotoxicity and long-term impact of high-dose steroids s uggest that caution and longer follow-up are required before the definitive introduction of taxanes into the routine care of patients with early breas t cancer. (C) 2000 Harcourt Publishers Ltd.