SABCS: Taxane Therapy After Anthracyclines Not Demonstrably Better for Breast Cancer

Michael Smith
SAN ANTONIO, Dec. 17 -- A course of taxanes following standard anthracycline-based chemotherapy for breast cancer had no discernible benefit, found a large British study.
After five years of follow-up, the regimens in the Taxotere as Adjuvant Chemotherapy Trial (TACT) led to essentially identical results in the primary endpoint of disease-free survival, reported Paul Ellis, M.D., of Guy's and St Thomas' Hospitals in London, at the San Antonio Breast Cancer Symposium.
There was also no difference in overall survival for the 4,612 patients, Dr. Ellis said.
In TACT, there were 2,073 women randomized to four cycles of 5FU, the anthracycline epirubicin, and cyclophosphamide (FEC)) followed by four cycles of docetaxel.
They were compared with 2,089 women randomized to either eight cycles of FEC or four cycles of epirubicin, followed by four cycles of cyclophosphamide, methotrexate, and fluorouracil (E-CMF). The choice was left to the physician.
The TACT study was intended to build on earlier studies that had showed a benefit for taxanes, such as docetaxel, when they followed anthracycline-based treatment, Dr. Ellis said.
Women were eligible for the trial if they had node-positive or high-risk node-negative invasive disease that had been completely excised.
An open question was whether the benefit was due to the drugs or the extra duration of therapy, so the TACT study was designed so that all patients would have eight cycles of treatment.
After five years, Dr. Ellis said:
Disease-free survival was 74.7% in the taxane arm and 73.9% in the FEC-only arm. The hazard ratio was 0.97, which was not significant.
Overall survival was 82% in the taxane arm and 81.8% in the FEC-only arm. The hazard ratio was 0.98, which also was not significant.
There were 291 breast cancer deaths in the taxane arm and 301 in the FEC-only arm.
Neutropenia and febrile neutropenia were significantly higher in the taxane arm, at P<0.001 for both.
Several nonhematological side effects were also significantly higher (P<0.001) in the taxane arm, including neuropathy and lethargy.
There was "no pattern of benefit" when the researchers looked at subgroups, although there was nearly significant improvement in disease-free survival among women who were estrogen receptor-negative and HER2-positive, Dr. Ellis said.
While the study may appear negative, it's actually "reassuring" to clinicians, said Lisa Carey, M.D., of the University of North Carolina in Chapel Hill, not part of the study, who moderated the session where the TACT results were presented.
"It does highlight that there are a number of active regimens," she said. If there are reasons to choose otherwise, such as diabetic neuropathy, "this gives us some reassurance that you don't have to include a taxane."
But, she added that TACT is only one of a number of studies, many of which have shown a benefit for the taxanes, that must be put in the "context of the body of evidence."
The study was supported by Cancer Research U.K., Pfizer, Roche, and sanofi-aventis. Dr. Ellis made no financial disclosures.
Primary source: Breast Cancer Research and TreatmentSource reference:Ellis PA, et al "Preliminary results of the UK Taxotere as Adjuvant Chemotherapy (TACT) Trial" Breast Cancer Res Treat 2007; 106 (Supp1): Abstract 78.