Tamoxifen was taken daily for five years. The chemo regimen used is called CAF, for "cyclophosphamide, Adriamycin and 5-fluorouracil."
In all, after accounting for study dropouts, 1,460 women received treatment.
The combined treatments of chemo plus tamoxifen increased the women's disease-free survival by 24 percent, Albain found. When her team looked at which delivery protocol worked best -- simultaneous tamoxifen and chemotherapy or chemo followed by tamoxifen -- the sequential approach was found to be better, giving slightly better disease-free survival.
Ten-year disease-free survival estimates were 57 percent for the combination group and 48 percent for the tamoxifen-only group, the researchers found.
However, women receiving chemo were more likely to have drops in white blood cells, important for fighting infections, the team noted. And they were also more prone to blood clots, congestive heart failure and other complications.
In a second study, Albain's team analyzed whether a gene test, called Oncotype DX, could predict which women would benefit from chemotherapy. Genomic Health, which makes the test, helped fund the study, along with the U.S. National Cancer Institute.
The test, which Albain said is already widely used, is done on the tumor itself. "This puts 21 genes together and comes up with a score," she said. The score -- low, intermediate, high -- predicts the risk of recurrence over 10 years if a woman used tamoxifen alone.
When the researchers performed the test on 367 specimens, they found a low score identified those women who may not need the chemo, despite the fact that they have cancer that spread to lymph nodes.
"This is a positive study, there's no question," said Dr. Joanne Mortimer
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