Weekly Paclitaxel in the Adjuvant Treatment of Breast Cancer

To the Editor: Sparano et al. (April 17 issue)1 compare the efficacy of two different taxanes, given either weekly or every 3 weeks, in the adjuvant treatment of breast cancer. It is striking that there were no significant differences in disease-free survival between the group of patients receiving paclitaxel and the group receiving docetaxel or between the group receiving weekly treatment and the group receiving treatment every 3 weeks, whereas multivariate analysis with the use of a Cox proportional-hazards model showed significantly longer disease-free survival in the group receiving weekly paclitaxel than in the group receiving paclitaxel every 3 weeks. Clinicians will have difficulties in drawing a definite conclusion from the study because of this disparity, which might be associated with unrecognized bias.