The Prosigna Breast Cancer Prognostic Gene Signature Assay (formerly called the PAM50 test), made by NanoString, is a genomic test that analyzes the activity of certain genes in early-stage, hormone-receptor-positive breast cancer.
Research suggests the test may eventually be widely used to help make treatment decisions based on the risk of distant recurrence (cancer coming back in a part of the body away from the breast) for postmenopausal women within 10 years of diagnosis of early-stage, hormone-receptor positive disease with up to three positive lymph nodes after 5 years of hormonal therapy treatment.
The Prosigna test was approved by the U.S. Food and Drug Administration in September 2013. The test received the CE mark, which is Europe’s approval, in 2012.
Knowing if a woman has a high or low risk of distant recurrence more than 5 years after diagnosis may be able to help doctors figure out whether 5 years or 10 years of hormonal therapy is better for her situation. Research has shown that taking tamoxifen for 10 years instead of 5 years can better lower the risk of recurrence and improve overall survival for many women. But if doctors knew that a woman had a low risk of distant recurrence, they might be able spare her the extra 5 years of hormonal therapy treatment.
What are genomic tests?
Genomic tests analyze a sample of a cancer tumor to see how active certain genes are. The activity level of these genes affects the behavior of the cancer, including how likely it is to grow and spread. Genomic tests are used to help make decisions about whether more treatments after surgery would be beneficial.
While their names sound similar, genomic testing and genetic testing are very different.
Genetic testing is done on a sample of your blood, saliva, or other tissue and can tell if you have an abnormal change (also called a mutation) in a gene that is linked to a higher risk of breast cancer. See the Genetic Testing pages for more information.
Who’s eligible for the Prosigna assay?
The Prosigna assay can only be used on breast cancers diagnosed in postmenopausal women that are:
- stage I or stage II and lymph node-negative
- stage II with one to three positive nodes
- have been treated with surgery and hormonal therapy
The Prosigna assay is performed on preserved tissue that was removed during the original biopsy or surgery.
How does the Prosigna assay work?
The Prosigna assay looks at the activity of 58 genes (called the PAM50 gene signature) to estimate the risk of distant recurrence of hormone-receptor-positive breast cancer from 5 to 10 years after diagnosis after 5 years of hormonal therapy treatment in postmenopausal women. Based on these activity levels, Prosigna assay results are reported as a risk of recurrence (ROR) score from 0 to 100 in two ways:
- node-negative cancers are classified as low (0-40), intermediate (41-60), or high (61-100) risk
- node-positive cancers are classified as low (0-40) or high (41-100) risk
If you decide to have the Prosigna assay, you and your doctor will consider a number of factors when deciding whether to continue hormonal therapy for 5 more years, including:
- your age
- the size of the cancer
- cancer grade
- whether cancer cells were found in nearby lymph nodes
- any treatment side effects
Insurance coverage for the Prosigna assay
Some insurance companies will pay for the total cost of the Prosigna assay, while others may pay a portion of the cost.
If you and your doctor are considering the Prosigna assay, talk to your insurance company to find out if it’s covered.
NanoString, the company that makes the Prosigna assay, offers the Prosigna Patient Support Program to help with insurance and payment issues. If you don’t have insurance or your insurance company doesn’t cover the Prosigna assay, NanoString may be able to help.
Other genomic tests
There are other genomics tests used to analyze breast cancer tumors. To learn more, click on the links below.
- The Breast Cancer Index test is used to predict the risk of node-negative, hormone-receptor-positive breast cancer coming back 5 to 10 years after diagnosis.
- The EndoPredict test is used to predict the risk of distant recurrence of early-stage, hormone-receptor-positive, HER2-negative breast cancer that is either node-negative or has up to three positive lymph nodes.
- The MammaPrint test is used to predict the risk of recurrence within 10 years after diagnosis of stage I or stage II breast cancer that is hormone-receptor-positive or hormone-receptor-negative.
- The Mammostrat test is used to predict the risk of recurrence of early-stage, hormone-receptor-positive breast cancer.
- The Oncotype DX test is used to predict the risk of recurrence of early-stage, hormone-receptor-positive breast cancer, as well as how likely it is that a woman diagnosed with this type of cancer will benefit from chemotherapy after surgery. The Oncotype DX DCIS test is used to predict the risk of recurrence of DCIS and/or the risk of a new invasive cancer developing in the same breast, as well as how likely it is that a woman diagnosed with DCIS will benefit from radiation after surgery.