When you’ve just received a diagnosis of breast cancer, you are faced with many different treatment options. Your mind is in a whirl with fear, confusion, and disbelief. While none of these feelings help decision making, there are some tests that can help: Oncotype DX and Mammaprint. 

These tests are genomic tests that analyze the activity of specific genes in the breast tumor. They can help you determine if your risk of breast cancer coming back is high or low, which can help you in making a decision about whether to have chemotherapy, radiation, or other therapies to reduce risk after surgery. 

There are two main types of tests – Oncotype DX and Mammaprint

Oncotype Dx has two tests for breast cancer – one for Ductal Carcinoma in situ (DCIS) – Oncotype DX DCIS and one for invasive breast cancer – Oncotype DX.  Mammaprint has one test for invasive breast cancer. Let’s look at these in greater detail. 

What are genomic tests? 

Genomic tests look at specific genes in your individual tumor and try to determine what is driving its growth. This is different from genetic tests which look at your inherited risk or predisposition for cancer. Genomic tests provide information that can help tailor your treatment plan to you as an individual. They are a type of personalized medicine. This is really important, because not all breast cancers are the same and, in fact, some breast cancers might have more in common with a prostate cancer than they do with another type of breast cancer. One size treatment definitely does not fit all.  

Oncotype DX DCIS

Image showing the incidence of DCIS from blog on CALMERme.comThis test is only for people diagnosed with DCIS or, as it is often called, “stage zero” breast cancer. In addition to general information such as tumor size, margins, and grade, Oncotype DX DCIS helps determine the likelihood of DCIS recurring or invasive breast cancer occurring within the next 10 years. 

It examines a sample of the tumor tissue that has already been removed during the lumpectomy for DCIS. By looking at the expression of 21 different genes in the tumor, it provides a DCIS score of between 0-100. The lower the score, the lower the risk of recurrence. Two scores are given, one to determine the risk of recurrence of DCIS and another for the risk of occurrence of an invasive breast cancer.

Knowing the DCIS score can help you decide whether to have radiation treatment  following the lumpectomy. If your risk of recurrence is low, then maybe you can spare yourself further treatment and the possible side effects that go with it. 

To be eligible for Oncotype DX DCIS, you need to have recently been diagnosed with DCIS and had lumpectomy surgery. The decision should be made in discussion with your doctor/oncologist.   

In the US, insurance might cover the cost of this test; the testing company will help you determine if this is the case and provide information to your insurers, as necessary. In the UK, these tests can be conducted under the NHS or privately. 

Many oncologists are now familiar with these tests for invasive breast cancer; sadly, the Oncotype DX DCIS test does not appear to be known by all oncologists, so it’s good for you to be proactive and start the discussion. Here is a link to the validation work done on the test that you can forward to your oncologist, and further links are given at the bottom of this post:

Clinical validation of oncotype DX DCIS

I definitely think it is worth having a discussion with your oncologist, sharing the references as necessary, and if you don’t get anywhere with the oncologist, talk to your family doctor or surgeon.  

Oncotype DX and Mammaprint

Both Oncotype DX and Mammaprint are genomic tests suitable for early stage invasive breast cancer. They both predict the benefit of chemotherapy or other types of treatment, as well as the likelihood of 10 year recurrence.

 They are similar tests but have some differences, as outlined below:

Comparison of oncotype DX and mammaprint for invasive breast cancer

Looking at this table can help determine if you are eligible for either of these tests. 

As with Oncotype DX DCIS, some insurance companies in the US will pay for these tests whereas some don’t include them in coverage. Both testing companies offer financial assistance or guidance, so it’s worth calling them to discuss if you are interested and want to check coverage. In the UK, these tests can be conducted under the NHS or privately. 

These tests are important because some of the cancer treatments, like chemotherapy, can have many side effects and are hard to get through. If there is little to no benefit in these treatments for you as an individual, then these genomic tests give you the confidence to not have a treatment that has greater potential for risk than for benefit.

Obviously the decision of further treatment is based on more than just these results. It involves detailed discussion with your oncologist, but also personal consideration of what you want and how you feel. Remember, you can take your time over treatment decisions. You might feel rushed, but take adequate time until you feel comfortable that you are making the right personal decision. These tests can go a long way in giving you confidence in your decision, but it is still a personal choice that needs to be right for you as an individual based on your mind and spirit, as well as your body.

Here are links to each of these three tests for more information

Patient information on Oncotype DX DCIS

Oncologist information on Oncotype DX DCIS

Patient information on Oncotype DX

Oncologist information on Oncotype DX

Patient information on Mammaprint

Oncologist information on Mammaprint

Let me know if you’ve had any of these tests and how they helped you.

We’ll talk about these types of tests for other cancers in the next post. 

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