The Oncotype DX® breast cancer test may change treatment decisions for more than a third of women with early, estrogen receptor-positive breast cancer. These results were presented at the 2010 San Antonio Breast Cancer Symposium.
The Oncotype DX breast cancer test measures the expression of 21 genes in a sample of tumor tissue. The test generates a Recurrence Score® that provides information about the likelihood of cancer recurrence and the likelihood of chemotherapy benefit in women with early-stage, estrogen receptor-positive breast cancer.
Previous studies have indicated that use of the Oncotype DX breast cancer test can influence breast cancer treatment decisions. Test results may, for example, change the treatment recommendation from chemotherapy plus hormonal therapy to hormonal therapy alone (or vice versa).
To provide additional information about the impact of Oncotype DX on breast cancer treatment decisions, researchers combined information from seven studies that enrolled a total of 912 patients.
- Physicians who used Oncotype DX changed their treatment decisions for over one-third of patients.
- Overall, there was a 28% reduction in use of chemotherapy as a result of the test.
- 4% of women had chemotherapy added to hormonal therapy as a result of the test. These women were initially considered low risk but were reclassified as high risk based on their Recurrence Score.
These results provide additional evidence that Oncotype DX can play an important role in treatment decisions for early breast cancer.
In another study presented at the San Antonio Breast Cancer Symposium, researchers evaluated a combination of the Oncotype DX Recurrence Score and factors such as tumor size and tumor grade. The combined score did not predict chemotherapy benefit as well as the Recurrence Score alone.
 Hornberger J, Chien R. Meta-analysis of the decision impact of the 21-gene breast cancer Recurrence Score in clinical practice. Presented at the 33rd annual San Antonio Breast Cancer Symposium, December 8-12, 2010. Abstract P2-09-06.
 Tang G, Costantino JP, Crager M, Shak S, Wolmark N. Comparing the prediction of chemotherapy benefit in patients with node-negative, ER-positive breast cancer using the Recurrence Score and a new measure that integrates clinical and pathologic factors with the Recurrence Score. Presented at the 33rd annual San Antonio Breast Cancer Symposium, December 8-12, 2010. Abstract S4-9.