What Is Oncotype DX?

Updated: Sep 24

By Abigail Johnston


When I was initially diagnosed with breast cancer in 2017, we thought I was Stage II. In light of that information, which we now know was erroneous, I chose to do a lumpectomy and once the tumors were removed, my doctor recommended that we have them tested to see if chemotherapy was right for me. My mother, at that time, was a 14 year breast cancer survivor and so this was news to all of us. As soon as my doctor suggested it, I did some research.


I discovered that the Oncotype Dx test providers a breast reoccurrence score. They explain it this way on their website:


“The Oncotype DX Breast Recurrence Score test provides a genomic-based, comprehensive, individualized risk assessment for early-stage invasive breast cancer in adjuvant and neoadjuvant settings. “



This score is recognized now as the standard of care by American Society of Clinical Oncology (ASCO®), the National Comprehensive Cancer Network (NCCN®), the St. Gallen Consensus panel, the National Institute for Health Care Excellence (NICE), the European Society for Medical Oncology (ESMO) and the German Association of Gynecological Oncology (AGO). That’s a lot of really smart and really dedicated people determining that this is a good test.


What is the TAILORX study?

Further, the testing was validated by the TAILORx study. The Oncotype dx website describes the study in this way:


“The landmark TAILORx trial enrolled 10,273 patients from over 1,000 sites who were candidates for adjuvant chemotherapy as per NCCN Guidelines and monitored their 9-year outcomes. The trial investigated the clinical utility of Oncotype DX Breast Recurrence Score test to confidently predict the patient population who will substantially benefit from chemotherapy. Patients with Recurrence Score (RS) results 0-25 showed excellent outcomes when treated with endocrine therapy alone, while patients with RS results 26-100 are known to have significant chemotherapy benefit.2 TAILORx also showed that standard clinical risk features alone are not sufficient to determine chemotherapy benefit - often leading to overtreatment or undertreatment of patients. Only the Oncotype DX Breast Recurrence Score test provides clarity for adjuvant treatment decisions.”


My then medical oncologist explained it this way – he said, “we have 20 years of tumors stored in a warehouse and we’ve studied their characteristics to create a database. This database then tells us the details of each person’s disease progression by looking at the genomics of each cell.” Basically, the history and experiences of more than twenty (20) years of the treatment of breast cancer gives us some indications of how cancer even now might behave and if chemo is indicated. The TAILORx trial was still going on at that time (in 2017) and the scores were validated even more after I underwent the testing.


Patients who are diagnosed with early stage, ER+, Her2- breast cancer, whether node positive or negative, are eligible for this test. I checked all the boxes for this test and off my tumor went after they’d cut it out of me to be tested.


Oncotype vs Mammoprint

One difference between the oncotype dx testing and Mammaprint (their competitor) is that while Mammaprint gives yes or no answer to the likelihood of chemo helping, the Onctoype dx test provides a numerical value that is either in the definitely no help range, the gray area range, or the definitely yes chemo would help range. My then medical oncologist preferred the more detailed information of the Oncotype dx test because it allowed him to apply his experience and clinical judgment to the result.


Oncoptype of 27

My result was 27, on the high end of the gray area. When we sat down with my then medical oncologist to discuss the next steps, he shared with us that in his experience, anyone with a score over 25 could benefit from chemo. His personal experience has been validated by the TAILORx trial. He left the decision to do or not to do chemo up to us, but the report we received showed us the difference in the danger of recurrence if I didn’t get chemo and if I did. The difference was over 10 percentage points and my husband and I decided that it would be best to proceed with chemo even though we’d been hoping to avoid it.


And thank God we did.


Starting Chemotherapy

It was at my first chemo appointment that someone in my medical oncologist’s office, by mistake, checked the box for my tumor markers to be tested. Since the tumor markers came back extremely high, I underwent more testing and we discovered that I’d actually been Stage IV from the beginning and the pain/limp I had in my right leg was a 5cm tumor that was threatening to shatter my right femur.


My then medical oncologist and my current medical oncologist have not been able to explain why the oncotype dx score wasn’t in the definitely would benefit from chemo range since the cancer had already spread through my blood to take up residence in my bones. That stumped the various tumor boards too.

The bottom line is that no test is 100% accurate and specific to each individual person. Yet, the additional information provided by the tests we have available assist the doctors in making the best possible recommendations for the patient to then decide what is best for him/her. Knowledge truly is power and the more information, the more knowledge, the better each team can determine the best treatment for the individual patient.


Check out the podcast with Abigail on Breast Cancer Conversations

More articles by Abigail:

Understanding Piqray

Germline Mutations and the ATM Gene

About the Author:

In 2017, at the ripe old age of 38, while living in Orlando, Florida, I was diagnosed with Stage IV Metastatic Breast Cancer after feeling a lump in my left breast while tandem nursing my boys, who are now 7 and 5. The summer of 2017 was a rollercoaster of emotions as I faced four body and life-changing surgeries amidst chemo and radiation.  Once the whirlwind had settled a bit and I’d completed transitioning my clients and staff at my law firm to another law firm, my husband, two boys and I moved to Miami to live with my family.  Looking back, I’m astonished at how much has changed, how much we have overcome as a family, and how everyone has adjusted.  While I don’t actively practice law, I use my education and training in a variety of ways for the breast cancer community, advocating for patients and thrivers.  I have started my own non-profit, Connect IV Legal Services, where I recruit lawyers to do pro bono work for Stage IV patients. I’m also active in many local and national organizations, volunteering and adding my voice to educate and persuade others to connect with and help my community.  You can connect with me by checking out my blog, www.NoHalfMeasures.blog, or following me on Twitter, Instagram, Facebook, LinkedIn, or YouTube! - Abigail Johnston

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