What is the Oncotype DX^® test?

• Overview
• When Should The Oncotype DX Test Be Used?
• How Was The Oncotype DX Test Developed?

Overview

The Oncotype DX test is a diagnostic test that can help women with some types of breast cancer learn more about the biological activity of their specific tumor. Along with other pieces of information, the results from the Oncotype DX test can help women and their doctors make decisions about whether or not to include chemotherapy in their treatment plan. It can also help indicate how likely it is that a woman’s cancer may return in the future (distant recurrence).

The Oncotype DX test looks at a group of 21 genes within a woman’s tumor sample—16 cancer genes and 5 control genes—to see how they are expressed, or how active they are. The results of the test are reported as a quantitative Recurrence Score^® result, which is a score between 0 and 100 that correlates with the likelihood of a woman’s chances of having her cancer return, and the likelihood that she will benefit from adding chemotherapy to her hormonal therapy.

The Oncotype DX test provides information in addition to standard measurements (such as tumor size, tumor grade and lymph node status) that doctors have traditionally used to estimate how likely a woman’s cancer is to return, and to help her make treatment decisions.

The Oncotype DX test is the only test of its kind incorporated in certain circumstances in both the American Society of Clinical Oncology^® (ASCO^®) and the National Comprehensive Cancer Network^® (NCCN^®) treatment guidelines. These guidelines are developed by medical experts to help doctors give their patients the best possible care. The Oncotype DX test has been ordered by over 10,000 doctors in over 55 countries for more than 175,000 patients (as of September 2010). In most cases, insurance covers the cost of the test.

For more information on the ASCO guidelines, click here.

For more information on the NCCN guidelines, click here.

When Should the Oncotype DX Test Be Used?

The Oncotype DX test should be performed after surgery (lumpectomy or mastectomy), but before you and your doctor make a final decision regarding adjuvant treatment (see figure below).

The Oncotype DX test is a non-invasive test that is performed on a small amount of the tissue removed during your original surgery (lumpectomy, mastectomy or core biopsy). This means you should not have to undergo any additional invasive procedures for the test to be performed.

After your surgical procedure, a tissue sample is preserved for further diagnostic testing. If the Oncotype DX test is ordered, the pathologist will send several thin sections of the preserved tumor tissue sample to Genomic Health. The Oncotype DX test results are then integrated with other laboratory test results to help you and your doctor formulate a treatment plan based on the unique characteristics of your tumor.

How Was the Oncotype DX Test Developed?

The Oncotype DX test was developed by a company called Genomic Health. There were 3 main steps in this development process:

1. Studying breast cancer genes. First, studies were performed to identify a large number of genes associated with breast cancer. Genomic Health performed its own studies in this area and also relied on the extensive databases developed as part of the Human Genome Project, as well as other sources in scientific literature. Many of these studies were conducted using research tools called microarrays, which are capable of performing whole-genome analyses of tissue samples and determining whether specific genes are expressed.
2. Clinical trials . Once highly relevant groups of breast cancer genes were selected, Genomic Health performed clinical trials with leading oncology centers to explore the correlation of gene expression (using the identified genes) with likelihood of breast cancer recurrence. Applying their proprietary technology, Genomic Health conducted trials looking at the gene expression profile of each individual tumor. They then compared each genomic profile with the patient's clinical outcome to see whether or not breast cancer recurred, thus determining which specific genes significantly correlated with recurrence.
3. A formula for determining recurrence. Scientists at Genomic Health selected a specific set of genes from these early studies. After analyzing hundreds of samples, the team developed a mathematical calculation that could help determine the likelihood of recurrence with precision. This formula results in one number, the Recurrence Score result, which provides valuable information to the healthcare provider. To verify its accuracy, this calculation was validated in additional clinical studies involving over 650 breast cancer patients. The gene expression analysis technology and the formula are the two key components of the Oncotype DX test.

American Society of Clinical Oncology (ASCO) and ASCO are registered trademarks of ASCO; National Comprehensive Cancer Network (NCCN) and NCCN are registered trademarks of NCCN. ASCO and NCCN do not endorse any product of therapy.