Dose variation and regimen modification of adjuvant chemotherapy in daily practice affect survival of stage I-II and operable stage III Taiwanese breast cancer patients.

To assess the effect of a non-standard dose and regimen of adjuvant chemotherapy on the clinical outcome in stage I-II and operable stage III Taiwanese breast cancer patients. Variables studied included treatment variation (regimen and dose of adjuvant therapy), lymph node status, tumor size, histologic grade, and hormone receptor status. Cox's multivariate regression analyses were used to select prognostic factors significant for disease-free survival (DFS) and overall survival (OS). In the multivariate analysis, lymph node-positive, a tumor size greater than 5 cm, grade III, hormone receptor-negative status, and non-standard adjuvant chemotherapy were independent prognostic factors for DFS and/or OS. Node-positive patients treated with standard adjuvant chemotherapy had a significantly better DFS (HR=0.6; P=0.032) and OS (HR=0.54; P=0.025) than those treated with non-standard adjuvant chemotherapy. Breast cancer patients receiving standard adjuvant chemotherapy have a better DFS and OS than those receiving non-standard adjuvant chemotherapy.