June 3, 2005
Drug Combo Increases Breast Cancer Survival
Serious side effects can occur, but experts say benefits outweigh risks
A combination of chemotherapy drugs can increase the five-year survival rate of women with node-positive breast cancer by about 7 percent, a new study finds.However, that gain doesn't come without a significant risk of serious side effects, researchers report in the June 2 issue of the New England Journal of Medicine.
The drugs are docetaxel and doxorubicin, and this combination plus a third drug, cyclophosphamide, is currently one of the standard treatments used for women with node-positive breast cancer. Node-positive breast cancer is a malignancy that has spread beyond the breast to at least one lymph node.
"We have a reasonable new therapeutic option that can improve the likelihood of cure of node-positive breast cancer patients. And the benefits [extend] to all subsets of patients," including both pre-and post-menopausal women and those with hormonal or genetic risk factors for more aggressive disease, said study author Dr. Miguel Martin, chairman of the Spanish Breast Cancer Research Group at the University Hospital in Madrid.
Not everyone agrees that the combination of docetaxel and doxorubicin is a good treatment option, however. In the May 18 issue of the Journal of the American Medical Association, French researchers stopped a trial of this drug combination because three women died from complications related to the chemotherapy.
"A high risk of life-threatening complications associated with the doxorubicin-docetaxel regimen was found in this open-label, controlled trial," the researchers wrote, and they added the combination shouldn't be used outside of carefully controlled clinical trials.
Martin disagreed with their conclusion, and said he was surprised they stopped their study so abruptly. Like any chemotherapy drug, these medications don't just interfere with cancer cell growth; they can also affect normal cell growth, which can cause toxic side effects. Often, chemotherapy medications can suppress the growth of white blood cells, leaving patients vulnerable to infection.
But, according to Martin, doctors also have medications called growth factors that can help counteract these effects. The French researchers should have considered adding such medications to their trial, rather than halting it altogether, Martin contends.
The new study involved 1,480 women with node-positive breast cancer, ranging between 18 and 70 years of age. All had surgery to remove cancer from their breast, and were randomly assigned to a treatment group within 60 days of surgery. Each treatment group received six cycles of chemotherapy.
Women in the TAC group (744) received 75 milligrams of docetaxel per square meter of body surface area, 50 milligrams of doxorubicin per square meter and 500 milligrams of cyclophosphamide per square meter, while women in the FAC group (736) received 500 milligrams of fluouracil per square meter, and the same dose of doxorubicin and cyclophosphamide.
The average follow-up time was 55 months. Two women from each group died within 30 days of receiving treatment, though only one death from each group was believed to be related to the medications.
The disease-free, five-year survival rate for the TAC group was 75 percent, compared with 68 percent in the FAC group. Overall five-year survival rates were estimated to be 87 percent for the TAC group and 81 percent for women in the FAC group. Treatment with TAC resulted in a 30 percent reduction in the risk of death, according to the study.
Infections were more likely in women in the TAC group, though there were no deaths attributed to infection.
This study, said Martin, "clearly shows that six cycles of the TAC combination is superior to six cycles of the FAC combination" after surgery for breast cancer.
"This was a well-done study that shows we have a very active agent in docetaxel," said Dr. Jay Brooks, chairman of hematology and oncology at Ochsner Clinic Foundation Hospital in New Orleans.
"The benefits of docetaxel clearly outweigh the disadvantages," said Brooks, who added that more liberal use of growth factor medications might help prevent infection and anemia caused by chemotherapy medications such as docetaxel.
The bottom line though, said Brooks, is that "if someone in my family had node-positive breast cancer, this drug would be used in their treatment."
To learn more about breast cancer and its treatment, visit the National Cancer Institute.