70-gene test may help guide treatment for some women with early breast cancer

Results of a 70-gene signature assay (70-GS) can influence recommendations about adjuvant treatment for patients with early breast cancer classified as intermediate risk by a 21-gene assay (21-GA), researchers say.

“The use of genomic assays in early stage ER-positive, HER2-negative breast cancer has become a standard practice for determining who should get adjuvant chemotherapy,” Dr. Hatem Soliman of Moffitt Cancer Center in Tampa, Florida, told Reuters Health.

“There are still some situations where the initial genomic test doesn't provide a clear answer. In these cases, the provider and patient may require additional information - almost like a second opinion - to guide them,” he said by email.

“However,” he added, “this is costly and should be done only in cases where the clinicopathologic information and initial genomic test are equivocal.”

Experts in cancer genetics weighed in on the findings in emails to Reuters Health.

Dr. Sofia Merajver, IHPI member and Scientific Director of the Breast Cancer Program and Director of the Breast and Ovarian Cancer Risk Evaluation Program at the UM Comprehensive Cancer Center in Ann Arbor said, “It is unknown whether survival would be improved by the change in therapy for those patients, and that is the gold standard.”

“Plus, the total expression of proteins is not sufficient to define the signaling processes inside cells, nor is a single static measure robust enough to predict long-term survival or time to recurrence, the outcome variables patients are truly interested in,” she observed.

“In essence, this paper just proves what doctors and patients are willing to do. The hope is that the value of adjusting the therapy was not overstated during this research, since so much (outcomes) data still needs to be collected.”