Researchers from the University of Rochester, Albany College of Pharmacy and Stanford University have reported that use of the OncotypeDX™ test to guide treatment decisions among women with node-negative, estrogen receptor-positive localized breast cancer results in good outcomes and acceptable cost. The details of this study were published in the March 15, 2007 issue of Cancer.

Although chemotherapy is recommended for many women with early-stage, node-negative breast cancer, the benefit of chemotherapy varies. Identifying in advance those women who are most likely to benefit from chemotherapy may allow for more individualized treatment. This would allow women who are unlikely to benefit from chemotherapy to avoid the toxic effects of treatment.

OncotypeDX™ is a genomic test that may be useful in determining which patients with newly diagnosed, Stage I or II, node-negative, estrogen receptor (ER)-positive localized breast cancer may benefit from adjuvant chemotherapy in addition to hormonal therapy. OncotypeDX™ predicts the risk of a patient experiencing a recurrence 10 years following diagnosis. Oncotype DX™ 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.

To evaluate the potential results and costs of using OncotypeDX™ to guide the treatment of node-negative, ER-positive breast cancer, researchers compared three different treatment approaches: 1) treatment of all women with tamoxifen alone; 2) treatment of all women with tamoxifen and chemotherapy; and 3) use of the OncotypeDX™ Recurrence Score (RS) to guide treatment. Using the RS-guided approach, low-risk women would be treated with tamoxifen alone, and intermediate- and high-risk women would be treated with tamoxifen and chemotherapy.

Compared to treating all women with tamoxifen alone, the RS-guided treatment approach resulted in longer life expectancy but higher (though still acceptable) cost.

Compared to treating all women with tamoxifen and chemotherapy, the RS-guided approach resulted in similar life expectancy and lower cost.

The study suggests that among women with early-stage, ER-positive breast cancer, use of the OncotypeDX™ test to individualize treatment decisions appears to produce good outcomes at an acceptable cost.

Comments: The use of the OncotypeDX™ test in breast cancer management is being further explored by an ongoing clinical trial known as TAILORx. For more information about this clinical trial, visit http://www.cancer.gov/clinicaltrials/digestpage/TAILORx.

Reference: Lyman GH, Cosler LE, Kuderer NM, Hornberger J. Impact of a 21-gene RT-PCR assay on treatment decisions in early-stage breast cancer: An economic analysis based on prognostic and predictive validation studies. Cancer. 2007;109:1011-8.

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