Impact of Oncotype DX on chemotherapy assignment: a retrospective single-center study on female breast cancer patients.

Panousis D1, Ntasiou P, Grosomanidis D, Chatzopoulos K, Paraskevakou G, Kontogianni P, Charitidou E, Xepapadakis G.

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Abstract

PURPOSE:

This study was designed to determine the Recurrence Score (RS) distribution and its associated risk assessments based on traditional clinicopathologic characteristics in a single-center breast cancer (BC) deriving cohort in Greece, and to evaluate the impact of the RS results on adjuvant treatment decisions applied in this cohort.

METHODS:

This was a retrospective, single-center study regarding Greek female patients with early-stage breast cancer (ESBC). From 2009 to 2015, 114 cases lacking unanimity in the multidisciplinary breast meeting (MDM) fulfilled the inclusion criteria. The RS of the Oncotype DX (ODX) assay was the main outcome.

RESULTS:

The mean RS in the sample was 16.38 (SD=6.87). RS was positively correlated with Ki-67 (p=0.008). A negative progesterone receptor (PR) was associated with a higher RS (p<0.05). RS was higher for cases of chemotherapy assignment (p<0.001). According to the oncologists' pre-DX assay recommendations, 62.8% of the patients would have been 'wrongly' assigned to chemotherapy, while 14.3% of patients would have not been recommended this treatment even though they should have. The overall chemotherapy recommendation was significantly altered after the ODX RS assay was carried out (p=0.008) and, in the sample, it diminished by 39.5%.

CONCLUSIONS:

The distribution of the ODX RS in the specific cohort of Greek women is similar to that reported in other geographic regions of the world. Knowledge of the RS resulted in a shift in treatment recommendations towards lower-intensity regimens and in a greatly reduced proportion of chemotherapy recommendations.