Genetic tests gauge breast-cancer recurrence risk

The Breast Cancer Index and the PAM50 and EndoPredict tests were all developed as prognostic assays. They were not designed to, nor have they been demonstrated to, predict patient sensitivity to an endocrine treatment or to help select a class of endocrine agent to use in therapy. Despite these limitations, the data presented on all three tests suggest that they perform well for discriminating recurrence risk among patients with hormone-receptor positive, lymph-node negative breast cancer. So far, there is not good evidence that they can predict outcomes in lymph-node positive patients.

Mitchel L. Zoler/IMNG Medical Media Dr. W. Fraser Symmans

The patients with the greatest potential for stopping treatment after 5 years are those who also have HER2-negative disease and grade 1 or 2 disease, similar to the women enrolled in the ABCSG 8 trial.

Another attractive feature of these tests is that they can be performed by local pathology laboratories, precluding the need to send specimens to distant testing sites. The pathology community has been waiting a long time to more fully participate in the genomic diagnostic/personalized medicine arena.

The next step is to confirm the reproducibility of these tests when used by a variety of labs, essentially guaranteeing quality control. You need a critical mass of labs working together and using these tests to be sure that everyone gets clinically valid and reproducible results. I expect this to happen during the next year.

Dr. W. Fraser Symmans is professor of pathology at the University of Texas M.D. Anderson Cancer Center in Houston. He said that he is a c-founder of, and has equity in, Nuvera Biosciences. He made these comments as an invited discussant for the reports at the meeting and in an interview.