Mammaprint Helps with Treatment Decisions
Some of you are likely familiar with the Oncotype DX test, a gene-testing profile that examines 21 genes of a breast tumor to suggest whether chemotherapy will be needed/useful. Results come back that a woman is in a low, medium, or high recurrence risk group. This information, along with the pathology report and AdjuvantOnline, helps that woman and her oncologist make the decision re chemo. There are some limitations to the value of the Oncotype--most specifically that it is only for women who are ER positive, and less validated in cases of one or two positive nodes and her2 positive disease. The Mammoprint is a newer test that examines 70 genes, but has the disadvantage of requiring fresh tissue.
When my second breast cancer was discovered in 2005, the Oncotype DX was very helpful. Since my lymph nodes had been removed the first time, in 1993, it was impossible to know whether there had been/would have been spread to the axillary nodes. There were a few other rather odd factors, so this then very new test was valuable. The imperfect result, for me, was that my number came back in the "intermediate risk" range--making it less than a fully clean decision. If the results are low or high risk, it is more obvious what is the right thing to do. For several reasons, including the absence of information about lymph nodes, I did have chemotherapy, and have never regretted that choice. (although I most certainly wondered about it during those months) It is often excrutiatingly hard for women to make the chemo decision, and any additional facts and data can help.
There is a newly released study about the value of this newer test, and I am guessing that it will become more and more widely available and used. Here is an excerpt from a Medscape article and a link to read more:
Confirmed: MammaPrint Predicts Treatment in Breast Cancer
The first prospective trial of the 70-gene-signature MammaPrint (Agendia) breast cancer test shows that it can help determine which breast cancer patients can forgo adjuvant systemic treatment. The results of the Microarray Prognostics in Breast Cancer (RASTER) study were published online January 31 in the International Journal of Cancer.
Of the women deemed to be low risk by the MammaPrint test, 85% chose not to undergo adjuvant chemotherapy, and 97% were disease-free after 5 years. Of the women deemed to be high risk, 91% underwent chemotherapy were disease-free at 5 years.
It might be prudent to incorporate MammaPrint results with the traditional clinical parameters, but only in patients older than 45 years for whom the value of adjuvant chemotherapy is unclear, said lead author Sabine C. Linn, MD, PhD, from the Department of Medical Oncology at the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital in Amsterdam.
The RASTER study is the first to prospectively evaluate the performance of MammaPrint. Decisions about adjuvant therapy were made on the basis of the 2004 Dutch Institute of Healthcare Improvement (CBO) guidelines, MammaPrint results, and preferences of clinicians and their patients.
Five-year distant-recurrence-free-interval probabilities estimated with MammaPrint and another clinical common tool, Adjuvant! Online (AOL) — used to assess the risk of developing recurrent disease and/or dying within 10 years — were compared.
5/23/13 I received this email today:
I handle public relations for Agendia, the company that developed the MammaPrint test. A few days ago, I came across your Feb. 2013 blog post on the recently published RASTER study. Thank you for highlighting this study!
I'm writing to ask if you could correct a factual error in your blog post concerning how the test is performed.
In your post, you noted that the MammaPrint test could only be run on fresh tissue. You may have picked up this misinformation from the original MedScape post. This was an error that MedScape subsequently corrected. Since early 2012, the test has been able to be performed on fixed tissue. As you might imagine, that advance has made a significant impact on the adoption and proliferation of the test.
Thank you, Hester, for considering this request, and for covering the first prospective breast cancer genomics study with clinical outcomes.
Dowling & Dennis Public Relations