[Impact of the 21-gene assay in decision-making during multidisciplinary breast meeting: A French experience]

The 21-gene assay (Oncotype DX(®)) test is used to estimate the risk of recurrence and to predict the benefit of adjuvant chemotherapy at an early stage of endocrine responsive breast cancers, without HER2 overexpression or amplification. This test corresponds to a recurrence score (RS), classifying patients into three groups (low, intermediate or high risk). The objective of this two-center prospective study is to define the impact of Oncotype DX(®) in clinical practice.

Between August 2013 and May 2015, an Oncotype DX(®) test was decided in multidisciplinary meeting, to certain patients with an indication of adjuvant chemotherapy for HR+ and HER2 negative cancers. The therapeutic changes after knowledge of RS were collected. An estimate of the economic impact was performed and a correlation between the RS and usual breast cancer prognostic markers was investigated.

Thirty-nine patients had a test, twenty-six (66.7%) of them have finally been no indication retaining chemotherapy. The economy obtained through the use of the test was estimated around 173,000euros. It has not been demonstrated correlation between the RS, the usual decisional and prognostic factors for breast cancer or with adjuvant! Online.

The RS has an additional decision value compared to other common decision criteria. Use of Oncotype DX(®) reduced in our experience the indications of adjuvant chemotherapy. The medical and economic impact could be significant.