BACKGROUND:

Oncotype DX is a 21-gene assay that calculates a risk of distant recurrence in women with estrogen-receptor-positive, lymph node-negative breast cancer. The purpose of this study was to determine whether the results of Oncotype DX influence the decision to administer chemotherapy.

METHODS:

A retrospective study was performed on 85 consecutive patients with estrogen-receptor-positive, lymph node-negative breast cancer who had an Oncotype DX recurrence score (RS) obtained. Tumor size, tumor grade, and treatment were then compared within each risk category. Statistical analysis was performed using STATA software.

RESULTS:

Tumors that were high grade and Her-2/neu positive more frequently had a high RS. Treatment was changed as a result of Oncotype DX in 44% of patients.

CONCLUSIONS:

Oncotype DX RS is significantly related to tumor grade and Her2/neu status. In this study, the treatment of 44% of patients was altered as a consequence of Oncotype DX RS.