Abstract
PURPOSE: Research has revealed that some patients who develop resistance to the first taxane treatment exhibit a moderate response to the second taxane treatment (incomplete cross-resistance between paclitaxel and docetaxel). However, which patients are most likely to respond to the second treatment remains unclear. The aim of this study was to determine the predictive factors for the efficacy of the second taxane treatment in patients resistant to the first. PATIENTS AND METHODS: We enrolled patients treated with paclitaxel and docetaxel (n=31) in this study. Using univariate and multivariate analyses, we determined the predictive factors for the efficacy of the second taxane treatment. Then, we assigned patients to one of the three groups: 1) those with a partial response (PR) to the first taxane treatment who subsequently became refractory (PR group); 2) those whose response was stable disease (SD) and subsequently became refractory (SD group); and 3) those whose response was the progression of the disease with the first taxane treatment (progression disease [PD] group). Furthermore, the response rates were assessed for each group. All statistical analyses were performed using JMP 11. RESULTS: Responses to the first taxane treatment considerably correlated with the efficacy of the second treatment in patients with a PR to the first taxane treatment (P=0.0061, univariate analysis; P=0.0056, multivariate analysis). In addition, response rates to the second taxane treatment in the PR, SD, and PD groups were 33.3%, 0%, and 0%, respectively. CONCLUSION: The response to the first taxane treatment was a predictive factor for the efficacy of the second taxane treatment in patients with a PR to the first. Thus, the second treatment is highly recommended for patients who exhibit tumor shrinkage (a PR) by the first treatment.