NEW YORK (Reuters Health) Aug 27 - A large trial comparing adjuvant anthracycline- and taxane-based chemotherapy in early stage breast cancer has shown no survival difference between the two, suggesting that any future progress in this area will come from therapies that target specific biologic types of breast cancer, rather than better chemotherapeutic regimens.
A third arm of the study that added gemcitabine to one of the regimens also showed no difference in survival.
"We have made huge progress in the adjuvant treatment of breast cancer but have reached a point where the addition of other drugs used in a non-selected group of patients does not improve outcome and increases toxicity," lead author Dr. Sandra Swain, the medical director of the Washington Cancer Institute in Washington, D.C., told Reuters Health by email. "The era of these large nonspecific trials is over. The future is treatment based on the biology of the tumor with therapies directed at specific targets."
The National Surgical Adjuvant Breast and Bowel Project conducted the large trial, which between 2004 and 2007 enrolled 4,859 women with node-positive early-stage breast cancer. The study was designed to compare optimal paclitaxel- and docetaxel-based regimens, as well as study the addition of gemcitabine to the paclitaxel regimen. Gemcitabine had previously been shown to improve outcomes in metastatic breast cancer when combined with paclitaxel.
Patients were randomly assigned to one of three regimens:
-six cycles of concurrently administered doxorubicin 50 mg/m2 plus cyclophosphamide 500 mg/m2 plus docetaxel 75 mg/m2 every three weeks;
-four cycles of doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2 every two weeks followed by four cycles of paclitaxel 175 mg/m2 every two weeks; or
-four cycles of doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2 every two weeks followed by four cycles of paclitaxel 175 mg/m2 plus gemcitabine 2,000 mg/m2 every two weeks.
At five years, as reported online August 12 in the Journal of Clinical Oncology, none of regimens led to a significant improvement over the others in either disease-free or overall survival.
Adverse events from drug toxicities, however, were different: the docetaxel regimen led to higher rates of neutropenia and diarrhea, while the paclitaxel-based regimens produced higher rates of sensory neuropathy.
Dr. Swain said she currently offers patients both the six-cycle regimen of docetaxel, doxorubicin and cyclophosphamide, as well as the four-cycle, dose-dense regimen of doxorubicin and cyclophosphamide followed by paclitaxel, explaining the potential adverse effects of each.
While targeted therapies like trastuzumab have improved the outcome for specific groups of patients such as those with elevated levels of HER2 protein in their tumors, few new options exist for other subgroups, Dr. Swain said.
When asked if there are currently any new options for HER2-negative early breast cancer patients - either biologic agents or new chemo regimens - Dr. Swain responded, "No, unfortunately not right now."
There is one study underway that adds everolimus to standard hormonal therapy in the adjuvant setting for patients with estrogen receptor-positive breast cancer, she added.
SOURCE: http://bit.ly/16Hkh0h
J Clin Oncol 2013.
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