Oncotype DX® Score: What Does It Mean?

The genes from your breast cancer can tell us whether or not you will benefit from chemotherapy. That is essentially what breast cancer genetic assays like the Oncotype DX® test are all about.

The Chemotherapy Decision

For a lot of women, the question of whether or not they will need chemotherapy looms large after a diagnosis of breast cancer. Months of treatment, nausea, hair loss, fatigue…not something to wish for unless you really need it. But now examining genetic assays of the tumor can guide oncologists in selecting just those patients who are truly going to reduce their risk of recurrence with chemotherapy and excluding those in whom treatment with chemotherapy would be too much treatment.

If you have been diagnosed with early stage invasive breast cancer in the past decade or so, you are probably familiar with some of the genetic assays that are available, and in the US, the Oncotype DX® test is the most commonly used. The Oncotype DX® test was really useful if you had a low score (didn’t need chemotherapy) or if you had a high score (would benefit from chemotherapy), but there was this big grey zone of an intermediate score.  With an intermediate score there was no clear guidance, and oncologists and patients struggled with whether or not to add chemotherapy to the treatment of that breast cancer. 

Does Your Score Put You on the Fence?

Wouldn’t it be nice to know what to do with an intermediate score? That’s exactly why the TAILORx trial was done.  In this trial women with hormone positive, HER2 negative, axillary node negative invasive breast cancer and an Oncotype DX® score of 11 to 25 were randomized to chemotherapy and hormone therapy or hormone therapy alone. This means that if you had an intermediate score, you were randomly assigned (similar to the flip of a coin) to receive chemotherapy or not.

What investigators learned is that there was a significant group of women in that intermediate range that did not need chemotherapy. Here are the big findings:

• For women older than age 50 and a recurrence score of 0-25, there is no benefit to chemotherapy over just hormone therapy alone.

• For all women with a recurrence score of 26-100, there was a benefit to adding chemotherapy to hormone therapy.

• For women 50 years old and younger and a recurrence score of 16-25, there was some benefit to adding chemotherapy.

That’s a lot of women who now won’t need to get chemotherapy or struggle with that decision.

If you have early stage invasive breast cancer, it is likely that you will have a genetic assay done. The information from that assay can help your oncologist determine whether or not you need chemotherapy. With the results of the TAILORx trial, oncologists can now define a much larger group of women who do not need chemotherapy.