Signatera Test. Is it truly helpful and worthwhile?

I have been taking the Signatera test for a number of years. It is but one test or tool in the toolbox that doctors and me use to assess either one of my 2 Stage 4 cancers. A single test and a single blood tumor test neither my doctors nor me rely on, get upset about, etc. We look for trends, rate of increase, and other confirming indicators.
Specifically, I did it for a removed ovarian brain tumor that was sent to Signatera in Feb 2024. I registered 0.47 - so not negative. But low. We watched it climb slowly to 7.88, and combined with my other tools of assessment, put a plan of action in place. But then it dropped to 7.0. Not doing anything special but retested and yes jumped to 10.51 in Dec 2025. Combined with PET, tumor markers, etc pivoted to weekly chemo in early Dec. My early March 2026 test showed my number dropping to 0.19. Now just a few more chemo treatments, PET looks better, CA125 way down. So my various tools once again confirmed each other. I meet with my oncology team next week but I suspect he won’t expect me to get to 0. Chemo will stop, we will keep me on some maintenance drugs, and I get to go back to monitoring and living my life. I understand my small “c” cancers are chronic conditions so tools for monitoring are very important to me, and their trends over time become equally important. Good luck!!

@peggydobbs it's definately confusing, all the different tests! I would only say, the most important thing is to find a qualified oncologist that you truly trust. It's fine to get opinions here, but we're not medical professionals. Some doctors refuse to order either the Signatera or the Oncotype test due to the fact that neither is 100% reliable.

@sosophia245

Agree.

I would say Signatera test is a valuable tool. I was diagnosed with stage 2c high grade serous endometrial cancer with abnormal p53 in April 2025. Following surgery, I started chemo which I could not tolerate due to it causing severe neuropathy, heart issues, and high blood pressure. My oncologist hematologist recommended the test. I just had a low positive result after 2 negative test results and am scheduled for a PET scan.
I feel the tests are extremely important and can help guide treatment choices for patients like me that cannot tolerate chemo. They also can help determine if treatment is working. There are some oncologists that are not on board with the tumor-specific testing yet. They seem to be more concerned that there is not enough research behind it. However, there is new evidence coming out that validates the accuracy and value of this type of testing as it tailors treatment to the patient. Unfortunately, Cancer treatment “cookie-cutter” approaches (6 rounds of chemo, etc) for every patient needs to be revisited. Each one of us is different and our treatment plan should be focused on what works for each patient. My opinion, of course.

YES! A LOT OF A LITTLE INFO ADDS TO PEACE OF MIND. 8/2022 STAGE 2 BREAST AND A WORLD WIND OF TREATMENTS, SURGERY, AND LIVING THE "HAPPY NEW ME AND LEARNING TO ADDRESS SIDE EFFECTS.
MY SIGNATERA LABS ARE ALIGNED WITH MY 6-MONTH CITY OF HOPE CHECK-UPS. ALTHOUGH THERE IS NOTHING 100%, IT HELPS TO TAKE ADVANTAGE OF TEST THAT CAN POSSIBLE DETECT CHANGES. THE GOOD NEWS, RECENTLY NATERA APPROVED MY MISC LABS TO BE TAKEN AT SITE. REASON, I HAVE SMALL ROLLING VEINS, USUALLY A CHILD BUTTERFLY PIC WORKS. AS A HEALTHY YOUNG WOMAN IN 20'S DONATED BLOOD TO RED CROSS. AFTER 3 DRAW AND 2 NURSES PUMPING THEY SAID, THIS IS HARD FOR BODY, NO NEED TO DONATE AND IF LABS ARE NEEDED LET THEM KNOW, HARD PIC,ETC.
WITH RADIATION AND CALCIFICATION, I AM OFFICIALLY A HARD PIC. I GO TO NATERA LABS VS WITH PRAYER TRAVELING NURSE HAS EZ POKE. CORPORATE IN RIVERSIDE, CA APPROVED PATIENTS TO BRING THEIR OTHER LABS IN. HOPEFULLY, THIS WILL FOLLOW SUIT NATIONALLY.

PLEASE DO LABS, YOU WILL RECEIVE REPORT ON SIGNATURA CHART, YOUR DR,ETC.
ALIGNING LABS WITH CHECK UPS AND SEMI ANNUAL PCP CHECK UPS WITH THEIR LABS, IT SOFTENS THE HOKI POKI POKS AND GOD WILLING A CHERRY ON TOP WHEN ALL LAB TESTS ARE IN OUR HEALING FAVOR. PLZ DO LABS.

@lifetraveler
I’ve had two Signatera tests both covered by Medicare parts B & G. However, I had to fill out an extensive questionnaire about my cancer details and family history so I think it’s case by case. I’ve been in treatment for recurrent breast cancer for 6 years, I have both the BRCA2 and CHEK2 mutations and a heavy family history of various cancers and early deaths. Both my tests were negative. Yay! Best of luck to all. ❤️

Hi! @peggydobbs :

Yes, what the other medical oncologist told you is true, that it's unclear how to change treatment plans based on the results of the Signatera test. This is because a Negative result suggests a lower likelihood of recurrence and the current ongoing treatments plan is on the right track, but a Positive result indicates the presence of ctDNA, oftenly identifying recurrence before it is visible on imaging. I think if the Signatera test shows a "positive result" with an elevating value of a patient's blood work over time, a competent medical oncologist should start thinking about something different to provide his/her patient with more effective treatments. This tool only indicates that it is time to re-evaluate the current treatment plan, but it won't tell folks how. Perhaps this is one of the reasons that not many medical oncologists favor this tool...

As for the question of whether Medicare covers the tumor markers blood tests, I truly don't know; for my PCP works at the hospital of a research university, she orders the quarterly blood work for me, I then go to the hospital for the blood test accordingly. Luckily for us, the values of my tumor markers have been staying relatively low ever since I started taking Anastrozole (one of the aromatase inhibitor medications treating patients with high ER+, PR+ BC), thus reassuring us the effectiveness of my current treatment. My PCP and I have an agreement though: should those values of tumor markers start trending higher than the normal range someday, we then need to bring it to the attention of my medical oncologist to re-evaluate my treatment plan. I guess we'll cross that bridge when we come to it... I am very grateful for my PCP's research oriented mind.

Sorry for such a lengthy note, my friend:(. Wishing you all a better journey ahead with hope, peace, and love!

To lifetraveler: Many thanks for this information. I'm glad I changed Med Onco as well! BTW, a different Med Onco told me that it's unclear if/how to change treatments plan based on results of Signatera. I think that's because circulating tumor DNA doesn't necessarily mean the existence of a solid tumor. Do you know anything more about this?

Also a question: are the blood tests for tumor markers covered by Medicare? So far, my Med Onco hasn't ordered any.
Many thanks in advance! Peg

Hi! @peggydobbs :

Oncotype DX test is a genomic test for early-stage, ER-positive, HER2-negative breast cancer that analyzes 21 genes in tumor tissue to predict the likelihood of cancer recurrence and the potential benefit of chemotherapy. I am so sorry that your first Oncologist seemed to miss the mark by telling you that it was not done for people over 70 thus delaying the treatment with Kisqali :(. Thank God that you changed your medical oncologist!

As for Signatera blood test for cancer patients, it is a personalized tool (custom-built for each patient by analyzing their specific tumor tissue to identify unique mutations), tumor-informed molecular residual disease (MRD) blood test by Natera (company name) that detects circulating tumor DNA (ctDNA) to track cancer recurrence (if there's any), and evaluate the effectiveness of this patient's ongoing cancer treatments. It is used to detect MRD after surgery for cancer patients with solid tumors, such as: colorectal, breast, lung, and muscle-invasive bladder cancer. This test is ordered by a physician, requiring both a tissue sample (from the patient's tumor) and regular blood draws (typically every 3 months) from the patient with stage II-IV cancers, as well as immunotherapy monitoring.

Sorry for such a lengthy note, hope it helps... I was over 70 when I had my surgery on 12/26/2023, and my surgeon sent my tumor tissue for an oncotype test right after the surgery. I am not qualified for a regular Signatera blood test; however, my PCP agrees with me to set up quarterly blood tests to check my tumor markers, such as: CA 15-3, etc., to make sure that my ongoing treatments plan is on the right track. I am very grateful for my kind-hearted PCP walking extra miles with me to assure me peace of mind!

Wishing you all a better journey ahead!

When I was first diagnosed, I asked for Oncotype test (for breast cancer). Was told test was not done for people over 70. Six months later, I changed medical oncologists, asked again for Oncotype. Result was a score of 29, so was put on Kisqali. I was already taking Exemestane. Medicare paid for the Oncotype.
If someone could comment on which test is best in which situations, I'd be grateful.