I was like most people when I was diagnosed with cancer in July 2012 – surprised, shocked and a bit of a deer in the headlights. “NOW, what do I do?” I asked myself.

I have a cancer that is difficult to treat: triple negative breast cancer (TNBC), which means my cancer does not grow because of hormones, such as estrogen or progesterone, nor another growth factor called HER2, a genetic mutation linked to the development of breast cancer. Currently, there are targeted treatments for those breast cancers. On top of that, I also have inflammatory breast cancer (IBC), which means my cancer spreads through the lymph system, and does not always present itself as a lump. It is an aggressive cancer, with a high recurrence rate to boot.

Probably the most difficult part was lacking more concrete information about my cancer. I needed knowledge, and little is still understood about TNBC and IBC. There were a number of genetic panels I could have had when I was initially diagnosed, such as the BRCA panel that identifies harmful changes in breast cancer, which for me came back negative. However, there really weren’t any concrete tests to tell me about my tumor that might have initially led me to a targeted treatment.

Without a known targeted treatment, I had to determine which chemotherapy option was “best” for me. Depending on the medical oncologist, treatments vary. Ultimately, making that decision isn’t easy. For IBC, I often tell people it’s like closing your eyes, throwing a dart at a dartboard, and seeing where it lands. Fortunately, I hit that dartboard with my treatment; after six months of chemotherapy, followed by surgery and radiation, all of my testing showed there was no indication of cancer.

In late spring 2014, my oncologist, Dr. Massimo Cristofanilli at Thomas Jefferson University, presented information to me regarding a new test, one even more sensitive than the one he employs to detect circulating tumor cells, which he uses to help predict pathological response to treatment and overall survival. This new test, Guardant360, is a blood-based, liquid biopsy that can detect much lower levels of circulating tumor DNA than a circulating tumor cell (CTC) test. For someone like me with an aggressive cancer, having this new tool seemed like a good idea.

My first Guardant360 test showed a very low level of circulating tumor DNA in my blood with a specific mutation. However, additional physical tests, an ultrasound and a CT scan showed no evidence of recurrence. Dr. C felt monitoring and following up on the Guardant360 test was in order to determine whether the mutation was genetic or somatic.

It wasn’t until November 2014 that a physical sign appeared. I noticed a tiny red spot on my chest in an area that was previously radiated, which I found through monthly photographs I had taken since my initial diagnosis. A skin biopsy and a new CT scan revealed both an IBC and TNBC recurrence, including a new hyperechoic lymph node that was not present the month before in an ultrasound. A follow-up to the Guardant360 test also revealed an anaplastic lymphoma kinase (ALK) mutation.

Armed with specific information regarding my tumor’s DNA, I started on an IBC clinical trial in January 2015 with a study drug called Romidepsin, which is currently used to treat both non-small cell lung cancer and neuroblastomas that have the ALK mutation. Finally, a potentially targeted treatment for my particular cancer, or as I like to think of it, a direct hit to the bullseye on the dartboard. Two subsequent Guardant360 tests (after six and twelve chemotherapy infusions) have shown that the ALK mutation is no longer present in my blood.

The Guardant360 test is a wonderful new tool that I see as a way for clinicians and patients to understand the genetic mutations present in the patients blood. No need for a biopsy – and no anesthesia, needles or surgery, which means no recovery time. It’s just a blood draw of two vials that is more sensitive, which can possibly lead to a targeted treatment when there previously was no option.

Who knows – if this test was around in 2012, I might have been able to find a targeted treatment that would have resolved my cancer with the initial treatment plan. The Guardant360 test has not only helped me make a more informed decision about my recurrence, but it also might be a life-changer in terms of a successful resolution of my cancer.

— Susan Tanner, a sales and marketing manager from Buffalo, has triple negative breast cancer and inflammatory breast cancer. Her doctors have been using Guardant360 since June 2014