Signatera Test. Is it truly helpful and worthwhile?

@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.

@pbnew
I had my first Signatera test in Feb this year, 2026. The cost is sliding scale in a sense and the qualification for price reduction is very generous (youvcan have a fairly high income) but it was hard prying the info and the reduction from them. They all eagerly wanted to help but it just took a lot of back and forth and them not knowing their own criteria. So keep at it. They said almost everyone pays $0 however i am paying $249 instead of the full $500 for each test and they recommend having this blood test every three months. It was not covered by Medicare or my insurance. So. My household adjusted income on tax return is about $70k.

My oncologist and a 2nd I went to in an attempt to get the test, both argued against it for the false positives and false negatives. Said it has not been thoroughly tested for the results. The other question both had, was how do you proceed with the results? If the result is false you could either do unnecessary testing or not test when you should.

I lobbied for it very hard!!! This the 2nd opinion. But neither would agree it was worth it.

@arminda Is it metastatic to the lymph nodes only or somewhere else like the bones? Those are both very low positives. Sometimes you can get positive results with cancer cells dying off.

@llthomson
It is ductal and they didn't get all the cancer when they done my mastectomy plus they removed 5 lymph nodes that were also positive for cancer, so now it's metastatic breast cancer. The signatera test was positive

@leolion811 and @arminda

So sorry ladies to read what you are going through. @davidwrenn had at great analysis of these types of test a while back. Both of you are coming at this test from completely different angles. My experience is a different viewpoint.
I have 2 different types of stage 4 cancer - breast since 2019 and the other - ovarian - percolating but only making itself known in late 2023/early 2024 when I got a brain tumor that was then biopsied. The docs have been using this test for several years BUT we have always considered it one tool in our toolbox. And never considered it the only tool.
@arminda The test is first considered on basis of positive & negative for detecting any residual tumor makeup circulating in your blood. A tumor is needed to start the process, not blood nor ascites fluid which when tested can indicate cancer but not to the level of specificity needed. Then circulating is key word. So the test is seeing a little something. Perhaps an early warning. What now becomes important is trend - maybe another test or two to see if the last read was accurate or what kind of growth. We watched my latest go from negative to below 1 to 2, then 4 and now 8. But we used other tools like biopsies, tumor markers, scans, visual, health etc to now address my cancer again. So don’t be alarmed but be observant. Ask questions and just rely on it as 1 of several needed observations to then make some decisions.
@leolion811 Sorry you are dealing with this journey again. Get the frustration. As I mentioned above, the tests are not perfect and just one early warning tool that good docs should follow and patients ask questions/get answers and advocate for themselves. I suspect that perhaps being localized might have impacted your results. The good thing is that you were using other methods to monitor yourself. No one should rely on only one test, bloodwork, scan, doctor opinion, etc in this process of determining whether one even has cancer, what is it and most importantly how much or yes how bad.
I am 6.5 years into my cancer journeys. I just had my 1st of 26th weekly chemo treatments yesterday. But I see my glass half full even as I start my now 4th time of dealing with it. I have an amazing life with speed bumps in it. The reality is everyone has to deal with speed bumps - ours are cancer. I just keep moving forward. Please do the same 🤗