Researchers affiliated with the Intergroup Trial E2197 have reported that Oncotype DX™ identifies women with hormone positive, HER2-negative breast cancer with 0-3 positive axillary nodes who are at a 3-4 fold increase in the risk of relapse despite standard chemotherapy and hormonal therapy. These results were presented at the 2007 annual meeting of the American Society of Clinical Oncology (ASCO) in June.

Women with node-positive, hormone receptor-positive, HER2-negative breast cancer often receive adjuvant treatment with chemotherapy and hormonal therapy. Nevertheless, some women eventually experience a recurrence of their cancer. If it were possible to predict which women are most likely to experience a cancer recurrence following standard therapy, these women could be targeted for studies of alternative treatment strategies.

Oncotype DX has been found to be a useful test in predicting the outcome of node-negative breast cancer. This test evaluates the activity of 21 genes from a sample of the patient’s cancer to determine the patient’s Recurrence Score. The Recurrence Score ranges from 0 to 100, with a higher score indicating a greater risk of recurrence.

The study presented at ASCO involved 465 women who had received chemotherapy and hormonal therapy for hormone receptor-positive early breast cancer. Of these women, 262 were node-negative and 203 had between one and three involved axillary lymph nodes.

• The Oncotype DX Recurrence Score was a significant predictor of recurrence risk in both node-negative and node-positive women.

• Women with a low Recurrence Score had excellent outcomes after standard therapy.

• Women with an intermediate or high Recurrence Score had a two- to threefold increase in recurrence risk compared to women with a low Recurrence Score.

Comments: This study suggests that among women with early-stage, hormone receptor-positive breast cancer, Oncotype DX predicts recurrence risk in both node-negative and node-positive women. A second study is underway to explore whether Oncotype DX predicts the magnitude of chemotherapy benefit in women with node-positive breast cancer.

Reference: Goldstein LJ, Gray R, Childs BH et al. Prognostic Utility of the 21-Gene Assay in Hormone Receptor (HR) Positive Operable Breast Cancer and 0-3 Positive Axillary Nodes Treated with Adjuvant Chemohormonal Therapy (CHT): An Analysis of Intergroup Trial E2197. Proceedings of the the American Society of Clinical Oncology Conference. Chicago/ IL.  2007. Abstract # 526.

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