Posted on March 8th, 2009 by
Use of Oncotype DX® contributes information about treatment of hormone-positive breast cancer with up to three positive lymph nodes in addition to that already available on Adjuvant! Online. These results were recently published in the Journal of Clinical Oncology.
The majority of breast cancers are hormone receptor-positive. These cancers are stimulated to grow by the circulating female hormones estrogen and/or progesterone. Treatment of hormone receptor-positive breast cancer often involves hormonal therapies that suppress or block the action of estrogen. These therapies include tamoxifen [Nolvadex®] as well as agents known as aromatase inhibitors. Tamoxifen acts by blocking estrogen receptors, whereas aromatase inhibitors suppress the production of estrogen in postmenopausal women.
In order to determine whether hormonal therapy is likely to benefit a particular breast cancer patient, it is necessary to accurately assess the hormone receptor status of the cancer. Currently, the standard test for hormone receptor status uses a procedure known as immunohistochemistry (IHC). It’s possible, however, that newer types of tests may provide comparable information about hormone receptor status along with other useful treatment planning information.
Oncotype DX is a genomic test that that has been validated for use in women with newly diagnosed, Stage I or II, node-negative, estrogen receptor (ER)-positive breast cancer. Studies have also suggested that the test may be useful for women with node-positive breast cancer. The test predicts risk of cancer recurrence as well as likely benefit from adjuvant chemotherapy. It evaluates the activity of 21 genes from a sample of the patient’s cancer to determine the patient’s Recurrence Score (RS). The RS ranges from 0 to 100, with a higher score indicating a greater risk of recurrence.
Researchers recently evaluated the effectiveness of Oncotype DX in helping to determine optimal treatment for patients with hormone-positive breast cancer. This study included 465 patients from a previous trial conducted by the Eastern Cooperative Oncology Group (ECOG) who had cancer that had spread to as many as three axillary lymph nodes. All patients had received standard hormone therapy and chemotherapy. Researchers compared recurrence risks among these women as determined through the Oncotype DX RS, clinical and pathologic features (as determined through physical examinations), scans, and laboratory analyses. As well, the combination of clinical and pathological features was considered plus an algorithm similar to that utilized by Adjuvant! Online, an online tool used by healthcare providers to evaluate clinical variables to help physicians and patients assess the risks and benefit of additional therapy after surgery.
Accuracy of predicted outcomes at five years for patients was compared.
The researchers concluded: “These results, combined with ASCO and NCCN treatment guidelines recommending the use of Oncotype DX, clearly demonstrate that the test provides critical information for breast cancer treatment planning that is not apparent by examination of clinical variables either alone or when combined using Adjuvant! Online.”
Patients diagnosed with early, hormone-positive breast cancer may wish to speak with their physician regarding their individual risks and benefits of testing with Oncotype DX.
Reference: Goldstein L, Gray R, Badve S, et al. Prognostic utility of the 21-gene assay in hormone receptor–positive operable breast cancer compared with classical clinicopathologic features. Journal of Clinical Oncology. 2008;26: 4063-4071.
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