Efficacy of docetaxel 60 mg/m2 in patients with metastatic breast cancer according to the status of anthracycline resistance.
OBJECTIVE
To evaluate the efficacy of docetaxel 60 mg/m2 in metastatic breast cancer (MBC) according to the status of anthracycline resistance.


METHODS
Ninety-nine patients with anthracycline-resistant MBC were treated with docetaxel 60 mg/m2 intravenously for a 90-minute period every 3 to 4 weeks. Anthracycline resistance was defined as primary and secondary resistance. Primary resistance was defined as progression during or within 6 months after completion of adjuvant anthracycline, and no MBC response to a first-line regimen that contained anthracycline. Secondary resistance was defined as progression after a documented clinical response to a first-line anthracycline treatment for MBC. Secondary resistance was further divided into three categories: (1) absolute resistance, or progression during treatment with anthracycline after a period of response; (2) relative resistance, or progression within 6 months after anthracycline administration ended; and (3) sensitive regrowth, or progression more than 6 months after the conclusion of anthracycline administration.


RESULTS
The response rate in the 99 patients was 35.4% (95% confidence interval, 30.1% to 44.8%). The response rates according to the status of anthracycline resistance were as follows: primary resistance (n = 46), 19.6%; secondary resistance (n = 53), 49.1% (absolute resistance [n = 16], 56.3%); relative resistance (n = 17), 47.1%; and sensitive regrowth (n = 20), 45.0%. The median time to treatment failure in patients with primary resistance was 2.9 months, compared with 5.2 months in patients with secondary resistance (P = .0022).


CONCLUSIONS
Docetaxel at a dose of 60 mg/m2 seemed to be effective in MBC with secondary resistance to anthracycline. The status of anthracycline resistance is important for the prediction of response to second-line treatment with docetaxel.
Ando
M
M
Department of Medical Oncology, National Cancer Center Hospital, Tokyo, Japan.
Watanabe
T
T
Nagata
K
K
Narabayashi
M
M
Adachi
I
I
Katsumata
N
N
D000328:Adult; D000368:Aged; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D000077143:Docetaxel; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D017239:Paclitaxel / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D016019:Survival Analysis; D043823:Taxoids; D017211:Treatment Failure
D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D043823:Taxoids; D000077143:Docetaxel; D017239:Paclitaxel