Gene expression profiling in clinical practice The impact of Oncotype DX and EndoPredict on decision making with increasing oncological work experience

Background:

Estimating distant recurrence risk is still challenging. OncotypeDX as well as EndoPredict are two competing, gene expression-based tests predicting the likelihood of recurrent diseases. We analyzed the difference in oncological decision making with and without the knowledge of gene expression tests as a measure of clinical work experience.

Methods:

This retrospective, monocentric study included 192 patients with G2, HR+, Her2- breast cancer between 2011 and 2015. All 192 patients received an OncotypeDX or EndoPredict analysis. A tumor board (TB) with knowledge of these OncotypeDX or EndoPredict scores served as baseline (Control group). This baseline was compared to the treatment decision (chemotherapy Yes/No) by oncologists with different experience levels who were not provided OncotypeDX or EndoPredict scores.

Results:

Within the EndoPredict group no difference between overall TB decision (chemotherapy Yes) 48.1% vs. 15+ years 39.2%, 5 – 15 years 39.2% and less than 5 years 50.6% group could be shown. Within the OncotypeDX subgroup we found some difference between overall TB decision (chemotherapy Yes) 35.3% and 15+ years 42.5%, 5 – 15 years 50.4% and less than 5 years 55.6% group. Here it seems that inexperience led to a significant increase in chemotherapy recommendation. For the Ki67> 25% subgroup analysis we found tumor board decisions at 50% (chemotherapy Yes) vs. 15+ years 80%, 5 – 15 years 100% and less than 5 years 100%.

Conclusions:

This pilot study yielded interesting results. Although numbers are small, rendering a subgroup analysis mostly descriptive in nature, it seems that the value of gene expression profiling increases with decreasing oncological experience.