Mary Royal is an expert at separating depression and pain from the joy she wants in her life. 

During the day, she is a forensic interviewer at a child advocacy center, often interviewing children who were abused or otherwise harmed. At home, she is an outwardly happy 54-year-old mother of four in Wichita Falls, Texas, who is part of a close-knit church community.

She’s spent years perfecting this separation and learning about ways to provide purposeful self-care on the days she needs it. Her home is healthy, her friendships are healthy, and she leans on them. 

But after she was diagnosed with breast cancer, went through months of treatment, and tried to separate the pain of cancer from the joy she wanted, many of her tools for healing weren’t working. 

“My job prepared me for learning how to put things in boxes. And how to walk away and not think about it again. I learned a lesson that if you go through a trauma like cancer, it gets very complicated,” she says. 

Much of her struggle today revolves around anxiety that the cancer will come back and take her from her family. It’s taken her nearly 18 months to feel like she can now put one foot down and really figure out what helps and doesn’t. 

She can’t drive by the oncology center. She doesn’t love imaging – still scarred from a false alarm after her treatment. One thing that has helped is a cancer DNA test introduced to her by an oncologist. 

The specific test Mary takes is Personalis’ NeXT Personal Dx, a circulating tumor DNA or ctDNA test. It is a blood draw that looks for trace fragments of tumor DNA. 

Personalis isn’t the first to use blood draws to detect cancer, but it is a pioneer in the field of ultrasensitive tests. The company’s research first made waves in finding lung and breast cancer recurrence months before they ever showed up on scans. 

There is a crucial distinction between the type of blood test you may have had for treatment and the blood test Personalis performs. This test is specifically designed for survivors looking to examine if their specific cancer has returned. 

To do the test, Personalis first takes a sample of your original tumor and does whole-genome sequencing on it to find a unique mutation signature. 

“Then we see if there are any hints of that mutation in the patient’s blood,” says Dr. Richard Chen, president and chief medical officer  at Personalis. 

Personalis has Medicare coverage for monitoring breast cancer recurrence in patients with Stage II and III disease and those with Stage I to III non-small cell lung cancer. It continues pushing for coverage in other types of cancers. 

The company is also pushing oncologists and cancer centers to use it earlier. Dr. Chen believes the test could help doctors hold off on unnecessary secondary treatments. 

“Right now, we still treat on averages. Maybe the average says you should have surgery and then chemo. But what if surgery got rid of cancer, and you can be really confident you are clear? You could spare the patient unnecessary treatment.”

Whether the ctDNA test is right for everyone is really a conversation between you and your doctor. I have not taken the test myself, nor have I read every research report on its efficacy. 

But for Mary, it helped. 

Ironically, Mary initially didn’t want to take the ctDNA test. She thought it would be anxiety provoking. 

I had the same expectation with genetic testing and have spoken with other survivors who said they have the same reaction to any blood test. After being poked and prodded, a lot of us have just had enough.  

But Mary’s doctor kept pushing, saying it’s just about catching anything early. The earlier is always better with cancer. 

“So, eventually, I said I’ll do this. In the beginning, I had so much anxiety about the test. But as tests have come back negative and negative, I’ve felt better,” she says. 

Mary takes the tests every three months and now has taken 13 total. All negative. 

She had a recent scare where she felt a bump on her chest and started panicking. She didn’t feel totally better until the ctDNA test came back. 

“We can celebrate that. You have to celebrate a negative result because there may be a time when it’s bad news,” she says.

Earlier this week, my colleagues at the BBC wrote about the growing research that shows how aspirin is lowering cancer risk for some people.

It’s a big deal for those with Lynch syndrome and others with a higher risk of developing cancer. It’s also another big reason why anyone with cancer in their family should think about getting a genetic test.

While testing can also be anxiety producing, the knowledge of any genetic abnormality can now help doctors improve your odds — at screening, at pre-treatment, and at life.