Jun 2 2005
A new Spanish study has found that a combination of chemotherapy drugs can increase the five-year survival rate of women with metastatic, node-positive breast cancer by 7 percent.
But the researchers say that gain comes with a significant risk of serious side effects.
The drug combination of docetaxel and doxorubicin, along with 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.
Study author Dr. Miguel Martin, chairman of the Spanish Breast Cancer Research Group at the University Hospital in Madrid, says that the treatment offers a reasonable new therapeutic option that increases the likelihood of a cure for node-positive breast cancer patients. He says 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.
Not everyone is in agreement with him that the combination of docetaxel and doxorubicin is a good treatment option, and in fact French researchers stopped a trial of this drug combination because three women died from complications related to the chemotherapy.
The French team say that they found a high risk of life-threatening complications associated with the doxorubicin-docetaxel regimen.
Martin who disagrees with their conclusion says he was surprised their study came to such an abrupt stop.
He says as with any chemotherapy drug, the medications don't just interfere with cancer cell growth but can also affect normal cell growth, which can cause toxic side effects. Chemotherapy medications can often suppress the growth of white blood cells, leaving patients vulnerable to infection.
According to Martin there are medications called growth factors which can help counteract these effects and the French researchers should have considered adding such medications to their trial, rather than halting it altogether.
The Spanish 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.
Although infections were more likely in women in the TAC group, there were no deaths attributed to infection.
Martin says the study clearly shows that after surgery for breast cancer, six cycles of the TAC combination is superior to six cycles of the FAC combination.
Dr. Jay Brooks, chairman of hematology and oncology at Ochsner Clinic Foundation Hospital in New Orleans, says the study was well-done and shows docetaxel to be a very active agent.
He says the benefits of docetaxel clearly outweigh the disadvantages, and adds that more liberal use of growth factor medications might help prevent infection and anemia caused by chemotherapy medications such as docetaxel.
Brooks says he would have no hesitation in using this treatment on a member of his own family who had node-positive breast cancer.
The French report can be seen in the May 18 issue of the Journal of the American Medical Association.
The Spanish report can be seen in June 2 issue of the New England Journal of Medicine.