Putting the Taxanes to Work: Unanswered Questions

Abstract

Adjuvant polychemotherapy improves the outcome of early breast cancer: 10-year relapse-free and overall survival are 44% and 51% respectively in patients treated with chemotherapy and 36% and 45% in controls (Early Breast Cancer Trialists Group 1992) Although encouraging in terms of treatment success, these results, also mean that, despite adjuvant chemotherapy, more than 60% of the patients have suffered relapse and nearly 50% have died. Improved therapeutic options are therefore necessary, particularly in node-positive breast cancer patients. Taxanes have shown promising activity in advanced breast cancer patients; in particular, two phase III studies have demonstrated that single-agent paclitaxel as first-line therapy induces response rates ranging from 25% to 33%, i. e., similar or slightly lower than those observed with doxorubicin, which range from 41% to 34% (Awada et al. 1997; Sledge et al. 1997). Moreover, docetaxel has shown a higher activity than doxorubicin: the observed response rates were 47% and 32%, respectively, in a population of patients pretreated with alkylating-containing regimens (Chan et al. 1997). Beside their activity, taxanes are very interesting because of their incomplete cross-resistance with anthracyclines: a response rate ranging from 27% to 48% was observed with paclitaxel in patients resistant to prior anthracyclines (Seidman et al. 1993; Wilson et al. 1994; Gianni et al. 1995a). Similarly, data from a randomized study showed that docetaxel has a higher activity than a regimen with mitomycin-vinblastine (overall response: 28% vs 14%) in anthracycline-pretreated patients (Nabholtz et al. 1997).