Why I Use a Signatera Test to Watch for My Rare Cancer in My Blood
How a Signatera Test Became Another Layer of My Uterine Leiomyosarcoma Monitoring
After surviving Stage IV uterine leiomyosarcoma, I do not depend on one test alone to tell me what is happening inside my body.
I have medical appointments.
I have imaging.
I have laboratory work.
I pay attention to symptoms.
I take maintenance cancer medications.
I also use a personalized circulating tumor DNA test called a Signatera test.
Signatera does not replace my scans.
It does not replace my oncologists.
It does not promise that cancer is gone.
It gives my medical team and me another piece of information.
For a rare and aggressive cancer that has already appeared in several parts of my body, I value every reliable piece of information we can obtain.
What Is Signatera?
Signatera is a personalized, tumor-informed blood test made by Natera.
The test looks for tiny fragments of tumor DNA in the bloodstream. These fragments are called "circulating tumor DNA", often shortened to "ctDNA"
To create the personalized test, tumor tissue and a normal sample are analyzed. A unique set of tumor-related DNA changes is selected to create an assay designed specifically for that patient.
Later blood samples are tested for DNA fragments matching that personalized tumor profile.
I think of it as giving the laboratory a description of what my cancer’s DNA looks like.
The later blood tests ask:
“Do we see matching pieces of that tumor DNA in this blood sample?”
One More Piece of the Cancer Puzzle
I do not see Signatera as a test that gives my doctors every answer. I see it as one more piece of the cancer puzzle.
My doctors also use scans, physical examinations, symptoms, bloodwork, pathology, tumor testing, medication response, and my full medical history. Signatera adds another type of information by looking for DNA fragments that match my tumor.
No single piece should make every decision by itself. When the pieces are considered together, they can help my doctors stay informed and make more personalized decisions based on my cancer, my treatment, and what is happening in my body over time.
Signatera Is Not a General Cancer Blood Test
Signatera is not a routine blood count.
It does not look for every possible cancer in every person.
It is not a universal screening test for people who have never had cancer.
It is personalized using information from a known tumor.
That is why the word **tumor-informed** matters.
The laboratory is not searching blindly for every cancer signal.
It is looking for selected DNA changes identified from the individual patient’s tumor.
It Is Different From Germline Genetic Testing
I have had more than one type of testing during my cancer journey.
Germline genetic testing usually uses blood or saliva to look for inherited genetic changes that may have been passed through a family.
Tumor biomarker or molecular testing examines genes, proteins, receptors, and other features inside the cancer.
Signatera uses information from the tumor to create a personalized blood-monitoring assay.
These tests answer different questions.
Germline Testing Asks:
“Did I inherit a cancer-related genetic change that may also matter to my family?”
Tumor Testing Asks:
“What biological features or DNA changes are present in my cancer?”
Signatera Monitoring Asks:
“Can we detect DNA matching my known tumor in this blood sample?”
Calling them all “genetic tests” can create confusion.
What Is Circulating Tumor DNA?
Cells release small pieces of DNA into the bloodstream as they break down.
Most of the cell-free DNA in blood comes from normal cells.
Tumors may also release DNA fragments.
The portion coming from cancer is called circulating tumor DNA.
The amount may be extremely small.
It can change according to factors such as:
The type of cancer
Tumor size
Tumor location
Amount of active disease
Treatment response
Timing of the blood draw
How much DNA the tumor sheds
Other biological factors
Not every cancer sheds the same amount of detectable DNA into the blood.
A test can miss cancer when the amount is below its detection level.
What Is Molecular Residual Disease?
The initials "MRD" may stand for molecular residual disease in this type of testing.
It refers to evidence of cancer detected at a molecular level when the amount may be too small to see through ordinary imaging.
A positive ctDNA test may indicate that tumor-related DNA is present.
A negative result means that the personalized tumor DNA was not detected in that sample.
A negative result does not guarantee that no cancer exists anywhere in the body.
Cancer may be present but not shedding enough ctDNA to be detected.
The disease may be too small.
The location may release little DNA.
The sample may have been collected during a period when the amount was below the test’s limit.
That is why Signatera should be interpreted with the entire medical picture.
My Test Was Created From My Tumor
Tissue from my cancer was analyzed.
The company used tumor information to create a personalized assay based on my cancer’s selected DNA markers.
Now, when I have the Signatera blood test, the system looks for those tumor-specific signals.
It is not checking whether I am still ER positive, PR positive, or ALK positive every few months.
Those tumor biomarkers helped guide my treatments, but Signatera monitoring is a different process.
The blood test looks for selected tumor DNA fragments matching the personalized profile developed from my tissue.
Why This Matters to Me After Morcellation
My original uterine mass was morcellated because it was believed to be a fibroid.
Later, I was diagnosed with Stage IV uterine leiomyosarcoma.
My cancer has appeared in my abdomen, back, and spine.
Morcellation may mechanically disperse cancer-containing tissue within the abdomen and pelvis when an unsuspected malignancy is cut apart. Uterine leiomyosarcoma can also spread through the bloodstream as part of its natural behavior.
Because my cancer story involves both potential tissue dispersal and distant spread, monitoring feels especially important to me.
I cannot look inside every part of my body.
Scans provide images of particular areas at particular times.
A tumor-informed blood test gives us a different type of information.
Signatera Does Not Show Where Cancer Is
A positive Signatera result does not tell doctors exactly where cancer is located.
It does not produce an image.
It does not show the size of a tumor.
It does not tell whether a suspicious area is in the lung, liver, bone, abdomen, or somewhere else.
Imaging and other medical evaluation are still needed.
Signatera may provide a signal that matching tumor DNA was detected.
The medical team then decides what that result means in the context of:
Previous results
Scans
Symptoms
Treatment
Timing
Other laboratory findings
The patient’s history
One Result Is Not the Whole Story
A single result can be important.
A pattern over time may provide more context.
The care team may look at whether ctDNA:
Remains undetected
Appears after previously being undetected
Decreases during treatment
Increases during treatment
Changes alongside imaging
Changes before or after surgery
Remains present despite treatment
Trends do not make treatment decisions automatically.
They may help the medical team decide what questions to ask next.
Natera describes serial testing as a method that may help clinicians monitor changes in ctDNA over time during treatment or surveillance.
A Falling Number Does Not Guarantee a Cure
When ctDNA decreases, it may suggest that the amount of detectable tumor DNA has fallen.
That can be encouraging.
It does not prove that every cancer cell has been destroyed.
A treatment may reduce disease without eliminating it.
A tumor may later develop resistance.
Another part of the cancer may behave differently.
The result needs to be considered with scans and clinical findings.
A Rising Number Needs Medical Interpretation
An increasing ctDNA result may raise concern that the amount of tumor DNA is increasing.
It does not explain by itself:
Where the cancer is
How large it is
Whether a scan will already show it
Which treatment should be used
Whether the result could be affected by technical or biological factors
A rising result is not something a patient should interpret alone.
It is information to discuss with the oncology team.
The doctors may decide to:
Repeat the test
Review the full trend
Order imaging
Reevaluate treatment
Investigate symptoms
Continue observing
Seek additional expert input
The next step depends on the complete situation.
Signatera Does Not Replace Imaging
PET, CT, MRI, X-ray, and other imaging methods allow doctors to see structures inside the body.
Signatera looks for tumor-related DNA fragments.
These tests do different jobs.
A scan may detect a physical abnormality without detectable ctDNA.
A ctDNA test may detect a molecular signal before a mass is visible on a particular scan.
Neither tool is perfect.
Using more than one type of monitoring may provide a more complete picture in selected patients.
The proper combination and schedule should be determined by the treating team.
It Does Not Replace Symptoms Either
Patients should not ignore symptoms because a recent Signatera result was negative.
Contact a healthcare professional about significant changes such as:
A new lump
Persistent or worsening pain
Unexplained bone or back pain
Shortness of breath
Neurological changes
Unexplained weight loss
Abdominal swelling
Bleeding
Severe fatigue
Changes in bowel or bladder function
Other persistent changes from normal health
A blood test is one tool.
The body may provide important information too.
It Does Not Replace Pathology
Signatera cannot take the place of examining a suspicious tumor under a microscope.
Pathology identifies what the tissue is.
Tumor molecular testing may further describe the cancer.
Signatera is intended to monitor for DNA matching a tumor that has already been identified and analyzed.
This distinction is especially important when discussing fibroids.
A Signatera test cannot currently be ordered for every patient with a uterine mass and reliably answer:
“Is this fibroid actually uterine leiomyosarcoma?”
The tumor-informed test requires a known tumor profile.
Signatera Is Not Yet a Preoperative Fibroid Test
I want to be very clear about what medicine can and cannot do today.
Signatera is not currently a standard preoperative blood test for distinguishing a benign fibroid from uterine leiomyosarcoma.
A woman cannot assume that a negative Signatera test before fibroid surgery proves the mass is benign.
There may be no established tumor profile from which to build the personalized assay.
Research into liquid biopsies, ctDNA, artificial intelligence, imaging, proteins, RNA, and other biomarkers may eventually improve preoperative diagnosis.
That is a hope for the future.
It is not yet a promise patients can rely on today.
Why I Believe Rare-Cancer Data Matters
Rare cancers have fewer patients.
That means researchers may have:
Smaller studies
Fewer tissue samples
Less long-term data
Fewer clinical trials
Less funding
Less agreement about monitoring
Fewer opportunities to compare patients
When patients participate in ethically designed research, registries, tumor banks, and data programs, researchers may be able to identify patterns that no single doctor or patient could see alone.
More data does not automatically create a cure.
It creates a better chance to ask useful questions.
Sarcoma Research Is Developing
Research has been examining tumor-informed ctDNA monitoring in sarcoma.
A 2025 Stanford-led study reported by Natera included more than two hundred sarcoma patients and more than two thousand samples. Leiomyosarcoma was a major subtype in the study, and the company reported strong test performance in that group. Because this information comes from the test manufacturer’s report and conference research, it should be considered promising evidence rather than proof that the test should be used identically for every leiomyosarcoma patient.
A peer-reviewed 2024 article also described the feasibility of personalized ctDNA monitoring in leiomyosarcoma and other gynecologic cancers while emphasizing the need for more evidence about how results should guide care.
Research is moving forward.
Clinical standards are still developing.
More Testing Does Not Automatically Mean Better Care
I am an advocate for access to testing.
I also believe testing must have a purpose.
Before ordering Signatera, patients and doctors should discuss:
What question are we trying to answer?
How will we interpret a positive result?
How will we interpret a negative result?
Will the result change imaging or treatment?
How often will testing occur?
Is the test covered by insurance?
What will happen if the result conflicts with a scan?
Is there evidence for this cancer type?
Who will explain the trend?
Testing can create anxiety when no one has agreed on what to do with the answer.
A clear plan matters.
I Do Not Want a Number Without a Doctor
Cancer patients can become focused on numbers.
We watch:
Tumor measurements
Blood counts
Liver levels
Kidney levels
Cholesterol
Blood sugar
Bone density
ctDNA results
A number may begin to feel like a verdict.
It is not.
A ctDNA result should be interpreted by professionals who understand the test, the cancer, the treatment, and the patient.
I want access to my results.
I also want medical guidance about what they mean.
The Emotional Side of ctDNA Monitoring
Waiting for a Signatera result can create its own form of scanxiety.
Even though it is a blood test, the result may carry enormous emotional weight.
A patient may think:
What if it turns positive?
What if the number rises?
What if it stays positive?
What if the blood is negative but the scan is suspicious?
What if the test detects something before doctors know where it is?
What if there is no clear treatment?
The possibility of earlier information can be reassuring.
It can also mean learning that something may be wrong before there is an obvious action to take.
Patients deserve emotional support as well as technical explanations.
A Positive Result Is Not a Personal Failure
A positive ctDNA result does not mean the patient failed.
Like with most tests, there are also possibilities of false positives.
It does not mean she lacked faith.
It does not mean she ate the wrong food.
It does not mean she did not fight hard enough.
It means the test detected DNA matching the tumor profile in that blood sample.
Cancer biology is not a moral judgment.
A Negative Result Is Not Permission to Ignore Follow-Up
A negative result can bring relief.
It should not become a reason to stop attending appointments, taking prescribed medication, reporting symptoms, or completing imaging recommended by the medical team.
Undetected does not mean impossible.
It means the personalized tumor DNA was not detected at that time within the test’s limits.
My Hope for AI and Future Blood Tests
I believe artificial intelligence may eventually help researchers find patterns that would be impossible for one human being to identify.
Imagine combining information from:
Tumor DNA
ctDNA trends
Pathology images
MRI and ultrasound features
Patient age
Menopause status
Symptoms
Tumor growth rate
Protein markers
Treatment response
Long-term outcomes
A carefully designed system might discover combinations that better distinguish a benign fibroid from uterine leiomyosarcoma before surgery.
That possibility gives me hope.
AI alone cannot make weak data strong.
Rare-cancer patients must be included.
Samples must be collected carefully.
Diagnoses must be accurate.
Privacy must be protected.
Researchers must validate their findings in new patients.
A computer pattern is not useful until it has been proven reliable enough to guide real medical decisions.
My Hope Is Earlier Detection
I want a future in which a woman with a uterine mass can have better answers before entering the operating room.
I want doctors to know more accurately:
Whether the mass appears benign
Whether it has concerning molecular features
Whether a gynecologic oncologist should perform the surgery
Whether the uterus should be removed intact
Whether morcellation should be avoided
Whether closer follow-up is needed
Earlier detection may allow more cancers to be treated before they have spread.
That could improve outcomes.
But we should not promise that one future blood test will eliminate every missed diagnosis.
Cancer is biologically complicated.
The goal is better information, not false certainty.
I Believe Genetic and Tumor Testing Should Be More Available
Cost prevents many patients from receiving testing.
Insurance rules vary.
Some people are never told that testing exists.
Others are told their rare cancer does not have enough evidence to justify it.
I believe medically appropriate germline and tumor testing should be broadly accessible, especially when the information may guide treatment or help families understand risk.
I also believe researchers need stronger rare-cancer data systems.
However, “free testing for everyone” requires decisions about:
Who pays
Which tests are clinically useful
How results are explained
How privacy is protected
How data is shared
What happens when uncertain findings appear
Whether the test improves outcomes
My advocacy goal is not testing merely for the sake of creating more reports.
It is useful testing connected to understandable care and responsible research.
Protecting Patient Privacy Matters
A cancer test contains deeply personal medical information.
Research and data sharing must protect the patient.
Patients should understand:
Who receives the data
How it will be stored
Whether it may be used in research
Whether identifying information is removed
Whether the patient can withdraw
Whether results become part of the medical record
Whether family implications exist
What insurance may cover
More data can help rare-cancer research.
Patients should not have to surrender control without informed consent.
My Friends’ Privacy Matters Too
Other patients have helped me understand cancer, treatment, testing, grief, and survival.
Some of those women are no longer alive.
Their stories belong to them and their families.
I can share what I learned without publishing their private test results, mutations, treatment histories, or medical details without permission.
The lesson is larger than any one person:
Serial ctDNA testing may provide another way for doctors to observe molecular changes during treatment.
That principle can be explained without exposing someone else’s medical record.
Questions to Ask About Signatera
Why are you recommending this test for my cancer?
Is there evidence supporting it for my cancer type?
What tumor tissue is required?
Is enough tissue available?
Does the test require a normal blood or saliva sample?
What exactly will the result report?
What does a positive result mean?
What does a negative result mean?
Will I receive a number or only detected versus not detected?
How often will I be tested?
Will testing continue during treatment?
What happens if the result rises?
What happens if it becomes positive while imaging remains negative?
What happens if imaging is suspicious but Signatera is negative?
Will the result change my treatment?
Is the test covered?
Could I receive a bill?
Who will explain the result?
Questions to Ask About Rare-Cancer Research
Is there a registry for my cancer?
Can my tumor tissue be included in research?
Is there a natural-history study?
Can my deidentified data contribute to a rare-cancer database?
Are there ctDNA studies for uterine leiomyosarcoma?
Is a clinical trial available?
How will my privacy be protected?
Will I receive research results?
Could participation affect my clinical care?
Who is sponsoring the research?
Patients should never be pressured into research participation.
The decision should be informed and voluntary.
What Signatera Can Do
Depending on the cancer and clinical situation, tumor-informed ctDNA testing may help doctors:
Look for molecular residual disease
Follow ctDNA changes over time
Add information during surveillance
Observe molecular response during treatment
Identify a new signal that deserves evaluation
Support research into recurrence and treatment response
The strength of evidence varies by cancer type.
What Signatera Cannot Do
Signatera cannot:
Guarantee that cancer is absent
Identify every cancer
Show exactly where a tumor is located
Replace pathology
Replace all imaging
Replace medical judgment
Promise that a treatment will work
Select a treatment automatically
Diagnose every uterine mass
Currently prove that a fibroid is benign before surgery
Understanding the limits prevents false reassurance and unnecessary panic.
What I Wish Someone Had Told Me
I wish someone had explained circulating tumor DNA in everyday language earlier.
I wish I had understood that tumor DNA can sometimes be detected in blood.
I wish someone had clearly separated inherited genetic testing, tumor molecular testing, and tumor-informed monitoring.
I wish rare-cancer patients were routinely told which research and monitoring options might apply to them.
I wish insurance coverage did not determine who could contribute to better data.
I wish every test came with a written plan explaining what doctors would do with the result.
Most of all, I wish we already had a reliable blood test that could warn a woman before a presumed fibroid was cut apart.
We do not have that test yet.
That is why research matters.
Hope for Today
My Signatera blood test does not give me certainty.
It gives me another way to watch.
My original tumor was analyzed.
A personalized assay was created.
Now blood samples can be checked for selected DNA fragments matching my cancer.
When the result is negative, I am grateful.
I still complete my other follow-up care.
If the result were to become positive or change, I would need my doctors to interpret it alongside scans, symptoms, treatment, and the rest of my health.
I do not see Signatera as a crystal ball.
I see it as another tool.
For someone with a rare cancer, another useful tool can matter.
I hope my results help me.
I also hope the growing body of rare-cancer data eventually helps women who have not yet been diagnosed.
Maybe researchers will discover a combination of ctDNA, imaging, pathology, symptoms, and artificial intelligence that gives doctors a stronger warning before surgery.
Maybe future patients will know more before a uterine mass is removed.
Maybe more women will receive expert surgery before cancer has spread.
Maybe fewer tumors will be cut apart because everyone assumed they were harmless fibroids.
That future is not here yet.
But every well-designed study, every protected sample, every accurately documented result, and every rare-cancer survivor who participates responsibly may help move us closer.
I cannot change what happened to my uterus.
I can help create awareness.
I can support research.
I can ask for testing that makes medical sense.
I can remind doctors and patients that rare cancer deserves data too.
Frequently Asked Questions
What is Signatera?
Signatera is a personalized, tumor-informed blood test that looks for circulating tumor DNA matching selected DNA changes found in a patient’s tumor.
What is ctDNA?
Circulating tumor DNA consists of small DNA fragments released by cancer cells into the bloodstream.
Is Signatera a germline genetic test?
No. Germline testing looks for inherited changes. Signatera uses tumor information to create a personalized blood-monitoring assay.
Does Signatera check ER, PR, and ALK in the blood?
Not in the way tumor receptor and biomarker testing does. It looks for selected DNA changes chosen from the patient’s tumor profile.
What does a negative result mean?
It means the personalized tumor DNA was not detected in that blood sample within the test’s limits. It does not guarantee that cancer is absent.
What does a positive result mean?
It means tumor DNA matching the personalized assay was detected. The oncology team must interpret the result with imaging, symptoms, treatment, and medical history.
Can Signatera show where cancer is?
No. Imaging or other evaluation is needed to locate disease.
Can Signatera replace scans?
No. It provides a different kind of information and generally serves as an additional monitoring tool rather than a replacement for all imaging.
Can Signatera diagnose uterine leiomyosarcoma before fibroid surgery?
It is not currently a standard blood test for determining whether an unbiopsied uterine mass is a fibroid or uterine leiomyosarcoma.
Is ctDNA being studied in leiomyosarcoma?
Yes. Emerging studies have examined tumor-informed ctDNA monitoring in sarcoma and leiomyosarcoma, but evidence and clinical standards are still developing.
Should every cancer patient receive Signatera?
Not necessarily. Use depends on the cancer type, available tumor tissue, evidence, clinical question, doctor’s judgment, access, and coverage.
Support on Your Journey
Waiting for blood-test results can bring the same fear as waiting for a scan.
Surviving Life Lessons Community Groups are being formed so patients and survivors can discuss surveillance, rare cancer, recurrence fears, research, and the emotional strain of living between appointments.
A test result is information.
You still deserve help understanding what to do with it.
Find Your Community
No one should have to face life's challenges alone. At Surviving Life Lessons, we believe in life survivors helping life strugglers. Explore our growing Community Groups to connect with others who understand your journey, share encouragement, and find hope through meaningful conversations. You'll also have the opportunity to introduce yourself and share your own story of overcoming. Your story matters. It may be the encouragement someone else needs to keep moving forward, reminding them that they are not alone and that hope is always possible.
Your Story Matters
We need your nice comments below! Your thoughts, experiences, and lessons learned might be exactly what someone else needs to hear today.
Drop a comment, Say Hello, and join the conversation.
Need More Personalized Support?
Everyone's journey is unique. If you're looking for personalized guidance, encouragement, or one-on-one support, explore our services to find the option that's right for you. We're here to help you take your next step with confidence and hope.
Helpful Resources for Your Journey
Explore our collection of books, journals, coloring books, and printable PDFs designed to encourage, inspire, and support you every step of the way.
References
Natera. “Signatera for Patients.”
Natera. “Signatera for Clinicians.”
Natera. “Signatera Frequently Asked Questions.”
**Natera. “What Is MRD Testing and How Can It Help Monitor Cancer Recurrence?”**
Natera. “Signatera for Gynecologic Cancers.”
Natera. “Largest Sarcoma Study to Date With ctDNA Analysis Demonstrates Excellent Performance for Signatera.”
Siy, Andrea B., et al. “Monitoring Response Using Circulating Tumor DNA in Patients With Advanced Gynecologic Malignancies.”
American Society of Clinical Oncology. “Circulating Tumor DNA Monitoring for Early Detection of Recurrence and Disease Progression in Sarcoma.”
National LeioMyoSarcoma Foundation. “ctDNA Educational Recordings.”
About the Author:
Deborah Ann Martin is the founder of Surviving Life Lessons, a published author, poet, speaker, and trainer with over 20 years of management experience across multiple industries. An MBA graduate, U.S. veteran, single mother, and rare cancer survivor, Deborah brings both professional expertise and lived experience to her writing on resilience, leadership, personal growth, and overcoming adversity. Her mission is to empower others with practical wisdom and real-life insight to navigate life’s challenges with strength and purpose.
.png){kind=small}
Comments