[Administration Order of FEC-DOC in Breast Cancer Adjuvant Chemotherapy Has an Effect on Toxicity].

Sequential administration of anthracycline - and taxane-based regimens has been established as standard adjuvant chemotherapy for breast cancer. In our hospital, FEC(5-FU/EPI/CPA) followed by docetaxel therapy has been used for this indication. Recently, we changed the sequence of FEC and docetaxel to reduce skin toxicities during the docetaxel phase. Since the effect of the administration order on efficacy and toxicity is not clear, we retrospectively compared the toxicities and relative dose intensity (RDI) of the administration orders. From January to December of 2012, 46 patients received FEC followed by docetaxel (AT group), while 42 patients underwent docetaxel followed by FEC during the same period in 2013(TA group). The incidence of severe hematological and major non-hematological toxicities was similar in the two groups. There was no significant difference in RDI between groups. However, grade 2 or higher hand-foot syndrome(HFS)during the docetaxel phase, which can be a reason for dose reduction or treatment termination, was more frequently observed in the AT group than in the TA group(54% vs 33%, p<0.05). Our data shows that the risk of HFS was reduced when the taxane was administered first. Interestingly, HFS significantly increased in the winter, regardless of the administration order(p<0.01).