Docetaxel Combo Effective After Surgery for Node-Positive Breast CancerKey Words
Breast cancer, adjuvant chemotherapy, docetaxel (Taxotere®). (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary.)
Summary
Women who underwent surgery for node-positive (spread to the lymph nodes) breast cancer, and who received additional (adjuvant) treatment with a drug combination containing docetaxel, were less likely to relapse or die than were women treated with a similar drug combination containing an older drug, fluorouracil.
Source
The New England Journal of Medicine, June 2, 2005 (see the journal abstract).
Background
Adjuvant (additional) therapy is commonly given to cancer patients after the primary treatment to increase the chances of a cure and reduce recurrence of the disease. Chemotherapy plays an important role in adjuvant therapy for women with breast cancer.
During the 1990s, a combination of drugs known as FAC (fluorouracil, doxorubicin, and cyclophosphamide) became a standard of care when it was shown to be effective as adjuvant therapy in this group of patients. Fluorouracil belongs to a family of drugs known as antimetabolites, and works by interfering in a certain way with cells’ ability to reproduce.
More recently, members of another family of drugs called the taxanes – for example, docetaxel (Taxotere®) and paclitaxel (Taxol®) – have been shown to be effective as adjuvant therapy in early breast cancer. Taxanes prevent the growth of cancer cells by affecting cell structures called microtubules.
The Study
In 1997, the Breast Cancer International Research Group began an international multicenter phase III clinical trial to compare the effectiveness of TAC (docetaxel plus doxorubicin and cyclophosphamide) with that of fluorouracil-containing FAC. The study involved 1,491 women age 18 to 70 who had undergone surgery for node-positive breast cancer within 60 days of entry into the study. Participants were randomly assigned to receive six cycles of either TAC or FAC.
Results
At a median follow-up of 55 months, the 75 percent of those women receiving TAC were alive and disease-free as compared to 68 percent of those treated with FAC. This represented a 28-percent reduction in the risk of relapse in the TAC group.
Overall survival after 55 months was 87 percent in the TAC group and 81 percent in the FAC group. This translates to a 30 percent reduction in the risk of death for patients who received treatment with TAC. However, TAC was significantly more likely to cause toxic side-effects than the older regimen. For example, women who received TAC were more prone to develop infections and suffered more from low blood counts and congestive heart failure.
Comments
This study “supports the use of TAC in place of the older FAC regimen,” wrote Edith A. Perez, M.D., of the Mayo Clinic in Jacksonville, Fla. in an accompanying editorial, adding, “one can consider TAC to be a standard of care….”
“This is a well done study that provides additional evidence that taxanes such as docetaxel have a role in the adjuvant treatment of some women with breast cancer,” said JoAnne Zujewski, M.D., a medical oncologist with the National Cancer Institute's Cancer Therapy Evaluation Program. Zujewski added that additional trials are needed to provide more specific information about taxanes so doctors are better able to determine who is most likely to benefit from TAC and what treatment schedule is most effective.
Limitations
In her editorial, Perez emphasized that the trial was restricted to women 70 years old or younger, “making it impossible to assess the benefit and tolerability [of TAC] in older patients.”
Another point Perez made is that since 1998, the standard treatment in the United States for women with node-positive breast cancer has been treatment with doxorubicin and cyclophosphamide followed by paclitaxel. How does this approach compare with TAC? The answer will depend on the results of other clinical trials, including one underway from the National Surgical Adjuvant Breast and Bowel Project (see the protocol summary).
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