Feasibility and therapeutic efficacy of weekly 1-h low-dose paclitaxel infusion for relapsed breast cancer.

The therapeutic efficacy of weekly paclitaxel infusion for relapsed breast cancer patients is not known. We assessed safety, feasibility, and therapeutic efficacy in a pilot study of weekly 1-h low-dose paclitaxel infusion for relapsed breast cancer in an outpatient clinic. Eighteen patients with relapsed breast cancer who had received prior chemotherapy regimens, including anthracyclines, mitomycin, and 5-fluorouracil beyond a second line of treatment were enrolled into the study. The dose of paclitaxel was between 40 mg/m(2) and 80 mg/m(2) per week in a 1-h infusion, and a treatment cycle was 4 weeks until there was no evidence of progressive disease. When a dose of 80 mg/m(2) was administered, the treatment cycle was weekly infusion three times with a 1-week interval per 4-week cycle. The mean treatment period was 5.5 months and the maximal length of administration was 8 months. The overall response rate was 44.4%, including 2 cases of complete response and 6 cases of partial response. Tumor response was observed in 3 of 7 cases of lung metastases (42.8%), 6 of 12 cases of soft tissue metastases (50.0%), and 1 of 3 cases of liver metastases (33.3%), whereas 8 cases with bone metastases did not respond. The mean time to response was 1.8 months and the mean response duration was 4.3 months. The dose between 31.5 mg/m(2)/wk and 79.7 mg/m(2)/wk was not associated with tumor response. Toxicities associated with weekly 1-h low-dose paclitaxel infusion were tolerable, and most were less than grade 2, including alopecia (100%), neutropenia (88.8%), flushing (66.6%), face edema (61.1%), numbness (55.5%), and myalgia (38.8%). There was 1 case of grade 3 neutropenia. Weekly 1-h low-dose paclitaxel might be a therapeutically effective, safe infusion and feasible as a salvage chemotherapy for relapsed breast cancer patients following failure of prior chemotherapy.