Biomarkers and more complex integration of panels in so-called molecular or genomic classifiers have reached the level of clinical implication after careful standardization (LDT) and clinical validation. Whether these molecular classifiers are actually used and alter treatment decisions is studied in this manuscript.

A genomic classifier (GC) with prognostic indication, Decipher (Genomic Health), aids in the decision for adjuvant radiotherapy (ART). In this study, the authors show that whereas the decision would have been “observation” in 39% of pre-genomic testing cases, the recommendation changed. The authors conclude that the use of GC substantially altered treatment decision-making, with a number needed to test of only 3.