Multigene Test Predicts Who Could Avoid Chemotherapy Despite Positive Lymph Nodes...

Multigene Test Predicts Who Could Avoid Chemotherapy Despite Positive Lymph
Nodes in Early Breast Cancer

SAN ANTONIO, Texas, Dec. 13 /PRNewswire/ -- Kathy S. Albain, MD, of Loyola
University Chicago, presented new data showing for the first time the
predictive value of the 21-gene Recurrence Score (RS) assay in patients with
node-positive breast cancer. The Breast Cancer Intergroup of North America
trial conducted by the Southwest Oncology Group (SWOG 8814) originally showed
that patients treated with 6 cycles of chemotherapy with cyclophosphamide,
doxorubicin, and 5-fluorouracil followed by 5 years of tamoxifen (CAF-T) had
superior disease-free survival (DFS) and overall survival (OS) compared with
patients treated with tamoxifen alone. This RS assay was performed on the
breast cancer tumor specimens collected on this trial, and measured the same
groups of genes already in use to predict outcomes and chemotherapy benefit in
lymph node-negative disease. Up until this study, standard practice was to
give chemotherapy to women with positive nodes. This study sought to determine
if the RS assay would be useful to predict who might avoid chemotherapy.
Dr Albain's group first showed that the RS is prognostic for 10-year DFS
and OS in patients treated with tamoxifen alone. They then compared DFS in
patients treated with tamoxifen versus patients treated with CAF-T across RSs.
They found that there was a large and significant benefit in DFS over 10 years
from adding CAF in patients with a high RS. In contrast, there was no benefit
in patients with a low RS. Interaction between CAF benefit and the linear RS
was significant overall and in the first 5 years. There was a strong carryover
benefit of CAF in high RSs out to 10 years, but no effect whatsoever in low
RSs long term. This interaction of RS with treatment effect was true in
greater than or equal to 4 positive nodes and 1 to 3 positive nodes.
In summary, this work demonstrates that: (1) a very strong benefit from
chemotherapy with CAF is predicted when the RS is high, and that (2) a low RS
may define a group of women with positive nodes who do not appear to benefit
from anthracycline-based chemotherapy.
Dr Albain concluded, "These data collectively challenge chemotherapy
mandates for patients with node-positive, ER-positive disease: not all benefit
from chemotherapy, whereas others derive greater benefit than previously
predicted. SWOG 8814 joins a suite of studies that provide a consistent
message regarding the value of the RS for individualized adjuvant therapy, and
for the first time shows its value in a population of women with node-positive
breast cancer who were treated with a tamoxifen-alone control. These findings
should be discussed with women diagnosed with early breast cancer who fit the
criteria for this study."
SOURCE San Antonio Breast Cancer Symposium

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