The Colon Club

Hi everyone,

Been a long time since I have posted here. I just got my 4.5 years CT Scans bill of clean health (Stage 3C rectal cancer survivor who had adverse cardiac event from 3rd round of chemo and did a clinical trial to avoid reoccurrence)

My oncologist at Cleveland Clinic Florida recommended I get the ctDNA test and I am scheduled to do the bloodwork on March 10th. I have been doing some reading online and searching this forum but having a hard time finding much information on it. My concern is false positives I have read that may occur. I am FINALLY getting to a point where I am starting to believe I made it and it isn't likely to come back this far out. Is there any data on false positive rates etc? Just wanted to see if anyone here has gotten one and if you would recommend it. Thank you!

I’m not an expert. Initially, my doctor told me that the cons are expense, difficulty getting insurance to pay for it and not really knowing what a positive result means as far as treatment options.

My research showed that even if I had a positive result, the information could actually be used to point to what protocol would be most effective against my specific cancer.

So I made up my mind that I would change oncologists until I found one that would fight to get me a ctDNA test. As I was getting up the nerve to tell my doctor that I regretfully needed to fire her, she said, “Remember that test you wanted? I got you into a study so that you can have it every 3 months and not need to pay for it.”

Fortunately my first test came back negative which did so much to relieve my anxiety and actually let me start living the post chemo life that I want to live.

I’m also 3c. CAE is not a good indicator for me at all. I don’t want the stress and radiation from getting a scan every 3 months instead of 6. So for me, the ctDNA test is just what I needed to feel like I’m getting the best surveillance possible. Now, I might feel differently if my results were different, but I’m the kind of person who feels better the more information I have, so maybe not.

I am stage 4. My test was also negative. Not sure what it means for the future. I did have full pathological response to chemo before surgery. Surgery found 0 cancer cells. Now I am finishing my post surgery chemo. My test in Jan was negative.

saltygirl wrote:I am stage 4. My test was also negative. Not sure what it means for the future. I did have full pathological response to chemo before surgery. Surgery found 0 cancer cells. Now I am finishing my post surgery chemo. My test in Jan was negative.

Personally I would take that as great news.

Ok, thank you both for the responses. I am going to move forward with it, apparently my insurance will cover it, so cost isn't a factor. Knowing is better then not knowing. I'm also concerned about the repeated radiation exposure from increased scans, (which my Onc said he would do every three months if positive) I am scheduled to go back to once a year post five year marker.

My onc (who is also a prominent ctDNA researcher) doesn’t recommend it to his general stage IV patients like me yet. His rationale is:

- the commercial test methods available currently aren’t accurate/repeatable enough to be reliable (despite what the companies marketing them might say), therefore
- we can’t rely on the results you get in either direction
- A negative result may give you some comfort, but you would still have to do the same surveillance anyway as we can’t rely on ctDNA alone (not to mention it is too costly and involved at present to do more frequently than CEA/scans anyway)
- A positive result will cause significant anxiety and probably reduce quality of life, but may not actually be a problem as we don’t know exactly what “positive” means (esp in stage IV NED), and
- We would not change treatment protocols (eg start/change chemo) etc on the basis of ctDNA alone anyway - you would always be followed-up with scans to confirm (and if no changes to scans it’s very unlikely treatment would change)
- There is virtually no data available for ctDNA in the stage IV setting, all research to date has been in stage II-III.

So I would say if you are stages I-III then you could definitely consider doing it, but it would be unlikely to change your treatment protocol and you’d probably be best to do it as part of a trial for the best accuracy and data. At stage IV, I can’t see a strong rationale to do it for surveillance outside of a trial (unless perhaps monitoring mutation burden during treatment in the case of things like v600e, etc).

Hi all,

Stage 2a (T3N0M0) with risk factor PNI.

I have a "non-specific" small lesion in liver, I will have TC-SCAN in two months to check evolution.

I am considering having the Signatera done, but i hesitate.

My CEA was very low at DX so I guess it wont be a good indicator.

If the results are negative it will certainly provide relief, but I will have to undergo the same follow up (CT-SCANS, MRIs and Colos...)

If the results are positive it will increase my already high anxiety and my oncologist is saying that he does not see how it impact treatement or follow up. He does not like the idea of making CT scans more frequent (perhaps he could recommend other imaging methods, but that's it). I really like my onc but I might consider getting a second opinion in this case.

Signatera is pricey here in Spain but not quite as much as to make it a strong deterrent.

What do you guys think?

I am on the same boat. I am on my 2nd cycle of Capox out of 4. Signatera contacted me because my previous oncologist had referred me. I spoke with my current oncologist and she would not recommend it. Her rationale is that it is data that you can’t act upon, so, why bother and potentially increase your anxiety level.

On the other hand, I wonder...if the results are good, wouldn’t that give you some peace of mind? And if the results are bad, sure, you wouldn’t change your actual cancer treatment, but wouldn’t you try harder on the nutrition, cancer fighting foods, alternative medicine stuff that you wouldn’t otherwise have been so keen on? I am, of course, worried about false positive/negative, but aside from that, if cost is not a factor, I would go for it...

I am also wondering....Why isn’t this test offered before you undergo preventative chemo? I had a surgery that supposedly took the tumors out, and I am currently undergoing CAPOX “just in case” there are any wandering cancer cells. Well, why is the test being offered while I am in the middle of chemo. If I had taken it before, and there were no lingering cancer cells, it would have saved me from having to do chemo? I am confused as to why the doctors say it is data that can’t be acted upon, when it seems that it could have been acted upon if tested at the right time?

Sunnycd wrote:I am also wondering....Why isn’t this test offered before you undergo preventative chemo? I had a surgery that supposedly took the tumors out, and I am currently undergoing CAPOX “just in case” there are any wandering cancer cells. Well, why is the test being offered while I am in the middle of chemo. If I had taken it before, and there were no lingering cancer cells, it would have saved me from having to do chemo? I am confused as to why the doctors say it is data that can’t be acted upon, when it seems that it could have been acted upon if tested at the right time?

According to a recent February 2021 article , this objective ("adjuvant chemotherapy de-programming for patients with undetectable, post-operative ctDNA") is under serious consideration but insufficient research has been done so far to allow it to become a standard for general use. It is expected that it will evolve eventually as a standard as soon as enough clinical trials have been done to establish its value as a standard.

There are in fact some clinical trials in existence right now for establishing this kind of data, for example, clinical trial NCT04264702 , which started recruiting 1000 Signatera patients in 2020 and which will conclude no sooner than 2022 with some preliminary data testing their objective #3

Objective 3. Evaluate survival in patients treated with adjuvant versus no adjuvant chemotherapy in patients with SIGNATERA™ negative test results [Time Frame: 2 years]
Proportion of patients with a negative SIGNATERA™ ctDNA test post-surgery that are still alive the end of the trial (during surveillance) treated with adjuvant versus no adjuvant chemotherapy

Presumably, the final data showing how many patients were still alive after the normal 5-year period of post-surgery surveillance will not be available until at least year 2025. This is what they mean by, "...Once ctDNA technology evolves to fulfill this promise...". It will not evolve to the required level until at least 5 years of clinical-trial based survival data has been accumulated, hence, not until at least 2025 at the earliest. NCCN will not list this as a viable treatment choice until clinical-trial data like this has been validated. This is why the test is not yet offered as an option in 2021.

...Once ctDNA technology evolves to fulfill this promise, several important objectives will be achieved: First, adjuvant chemotherapy could be withheld in patients with undetectable, post-operative ctDNA, who would ordinarily be considered high risk and receive treatment with adjuvant chemotherapy according to current guidelines...
Reference: https://www.onclive.com/view/ctdna-guided-mrd-assessment-enters-new-horizon-in-colon-cancer

I’ve tried to talk to my oncologist about getting ctDNA testing done but he said it will provide no benefit and they are just looking for $. Results will not change treatment, and will likely just cause more anxiety. Not sure if I agree but if it won’t change treatment, I’m not sure if I want to know. My next CT Scan and colonoscopy is next month and I’m already going through so much anxiety. I feel like every pain/symptom I feel is cancer . If I had a positive ctDNA test, then couldn’t do anything about it until the next scan, then it would just freak me out I think.

Where this is still experimental I wasn't going to put much stock into it with my wife. She is a stage four and had a re-occurrence about 16 months ago. It was removed other than where the tumor was against an artery and they scraped what they could off, she did additional radiation and 6 months of FOLFIRI. She will have been on maintenance chemo for a year in July. Since than 2 PET scans SUV in the tumor area has been below 3 and the second PET result was below 2 I think. She had a clean CT in March but her cea has increased from 1.2 to 1.8 and has been holding at 1.8. Her Onc really like the ctdna test and my wife liked it. The company is paying for it and she is the second stage four in the office to get it. The results came in yesterday as negative with no ctdna found. I took it as great news but not sure it changes anything. Maybe in July and after her next scan maybe we can decide it maintenance chemo is needed.

well i just got it and im a stage IV survivor around 3 years but my cea has been increasing recently so more pet or ct scans sooner like every 2 months he said

I will say that it has helped me. I’m 3c so even with surgery and Chemo, there is still a pretty good chance I could have a recurrence. I get a Pet scan every 6 months and a ctDNA test every 6 months. So far, I’ve had 2 negative tests. I understand that this doesn’t mean the cancer isn’t going to come back or spread, but I’m still glad to know that my chances may be just a little better. And I’m able, mentally to make plans for the future that I wasn’t willing to do before.

If I get a positive in the future, my oncologist will agree to scans every 3 months rather than 6. The ctDNA test was our compromise because she didn’t want me to have the radiation from scans every 3 months, and I didn’t want to go 6 months without new info.

I am happy you got a negative test. And yes i was getting Pet scans i think every 3 or 4 months now I will be getting them every 2 months along rising CEA with some luck they can catch it early and remove it.