The use of the Oncotype DX test reduces the rate of adjuvant chemotherapy recommendations.
Few in-depth analyses have been performed on this decision-making process.We retrospectively
analyzed patient data based on available Oncotype DX test results (RS) irrespective
of nodal status at a single center. We collected recommendations from six oncologists,
first without RS (pre-RS) and then with RS results (post-RS). We investigated changes
in recommendations, agreement between oncologist decisions, and the effect of different
National Comprehensive Cancer Network (NCCN) recommendation categories (for, against,
and considering chemotherapy).Data from 201 patients were included in the analysis.
Recommendation of chemotherapy decreased by an average of 39.5%. Agreement improved
substantially with RS, with a kappa value pre-RS of 0.37 (fair agreement) and post-RS
of 0.75 (substantial agreement). Discordance remained substantial in cases where the
NCCN recommendations considered chemotherapy only (32%). Pre-RS consensus against
chemotherapy predicted low RS results (50 out of 51 patients). Post-RS consensus was
highest in the NCCN chemotherapy recommendation group.The Oncotype DX test substantially
improves decision accuracy in recommending adjuvant chemotherapy. It may be further
improved with a consensus decision. In the case of pre-RS consensus against chemotherapy,
the test can be spared.
