Understanding CTC (circulating tumor cells) results

SyrMom · July 2012

I wonder what your exeriences have been with this lab result and what your understanding of it is. I've been reading and asking questions regarding this, but would like more input.

To put it in a nutshell, my limited understanding is the goal is to have a 0 score. For metastatic disease a score of <5 indicates the treatment is working. A score of anything above 0 indicates shorter survival rates, however, I don't know if this is true of those with stage IV.

Any input?

nancyh · July 2012

Dear SyrMom,

From my understanding, the CTC test is used in a couple ways. If you are newly diagnosed stage 4, it can be a predictor of overall survival (higher scores being considered worse, sometimes the scores can be quite high, as in the hundreds or maybe even thousands).

The other way it is used, which is the case for me, is as a surrogate tumor marker. My CTC has been slightly elevated (4 initially) when my cancer is really awful and/or progressing, even though my traditional tumor markers have always been normal. My CTC dropped to zero as my treatment started working, then creeped up to 1 when I had my first progression. It is a subtle change, but has been really helpful to provide an indication that a particular treatment might not be working.

My sense is that the CTC is still a relatively new test and the docs don't know exactly what to make of the scores other than "low is good" and "trending higher is bad". As with so many things with this crazy disease, there are no crystal balls for prognosis.

Best wishes to you. Glad you asked the question, I've been getting regular CTCs for years now and feel it is a topic that isn't widely discussed.

Hugs,

NancyH

GatorGal · July 2012

As far as I know, I've never had the CTC test done. Do most onc's order it?

nancyh · July 2012

Glenna,

I don't think it is routinely done and it can be tricky getting insurance to pay for this at nearly $600 a test. My onc has me get it because my other tumor markers have not been helpful, so this at least gives us an idea of when things are getting worse without needing to scan me everytime.

As a total side note, my CA 27/29 was recently a little elevated (first time in nearly 3 years), so we are watching it now to see if that's a possible marker for me. Things can and do change with TMs, which I find interesting.

SyrMom · July 2012

Thanks for the input, this disease certainly is crazy. To think CTC's can go into the hundreds and yet for some other women a 4 is when they were at their worse, makes no sense. My TM's have always been in the normal range too, but have been slowly creeping up over the past 6 mo. That's why the sudden showing of CTC's prompted a change in tx.

Nancyh - how often are your CTC's run?

nancyh · July 2012

For a while, I was getting CTCs monthly. My onc had me "on a short leash" when I was on faslodex and wanted to make sure nothing was progressing and it obviously wasn't practical to scan me that often.

tammie · July 2012

Syr mom way off topic but are you from syr. NY by chance??

SyrMom · July 2012

yes

CoolBreeze · July 2012

You aren't confusing tumor markers with CTC's, are you? I didn't think CTC's were in wide use yet - not quite out of the lab. Tumor markers, of course, many of our oncs use.

Maybe I'm wrong and they are in oncologist's offices now? Last I read they weren't.

AnnE16 · July 2012

Coolbreeze,

My onc has been using CTC's for the past 3 1/2 years. However, I have had 2 doctors tell me in the past 2 weeks that this test isn't necessarily reliable b/c if the test isn't testing what your cancer cells express than you may not be getting an accurate reading. And then a doctor today just told me he had a patient with cancer everywhere and he ran the CTC to test it and it came back zero. So he is definitely not a believer in this test. He said they need to "clean it up" and make it better! Blood work for me always showed normal even the day I was diagnosed with stage 4 so I have to rely more on scans rather than bloodwork.

Katarina · July 2012

My ONC said the same thing --- lots of false positives and positive negatives that are not consistent with the patient's real situation. It's a tricky test and I believe only the Mayo clinic is running trials of it.

Hugs

Kat

Fitztwins · July 2012

When I was first dx we did this test a few times , my number was always 0. My doc and I never found it to be a helpful tool.

raro · July 2012

My "regular" tests (CA 27, etc) have always been completely unreliable. When the CTC test came out, by onc was excited by it and wanted to see if just maybe it might be more reliable. For me, they are a very good indicator of progression. He said that actually anything under 4 is considered negative. I could tell the Faslodex was working because I went from 28 to 14, then halved again to 7. Then I went to 8 the next month...and 41 the month after that. And yes, the CT/bone scans then showed progression. So for me, it has been a great way to find out very quickly if the treatments are starting to fail.

SyrMom · July 2012

I read the same thing regarding progression. I read the CTC can indicate a tx is beginning to fail before it shows up on scans. Wouldn't it be nice if this were true so we were able to have a change in tx to ward off significant progression & perhaps learn what's happening in our bodies with less scans (too much to hope for?). Would be great if this ends up becoming a reliable indicator for the onc's to use.

SyrMom · July 2012

Coolbreeze - CTC stands for circulating tumor cells; TM is for tumor markers. The CTC is a much newer lab and still be understood (from my understanding). I have read a CTC under 5 indicates metastatic disease is responding to tx; over 5, the opposite.

Tina2 · July 2012

My onc ran the CTC test on my blood a year ago when I was first diagnosed at Stage IV. The result was 0. I don't think he's run it since.

SyrMom · July 2012

I've had the CTC run periodically since I was first dx (I believe every 3 mo). It was always 0 until this month! That, coupled with a 3 mo trend upwards in my TM (but considered in the normal range) prompted a change in my tx.

I, too, have been stage IV from the get go. Hard to understand; this disease is so insidious.

CoolBreeze · July 2012

Thanks! Yes, I knew what they were. I just didn't know the CTC was actually in use in oncologists' offices yet. I thought it was still being studied.

SuperFoob · July 2012

I have had 5 CTC blood tests, all requested by my ONC. The blood is put in a special tube (actually two tubes now in case they need more for some reason and it can't be done on a Friday as they need the blood "fresh") and the test is conducted by CellSearch.

My first CTC was drawn after the second or third neoadjuvant chemo infusion. It came back "2".

2nd test was taken at last chemo infusion. Came back "1".

3rd test was done after surgery. Came back "0".

4th test was done with less than one week left in Radiation treatment. Came back "0".

5th test done about third month into taking Letrozole. Came back "0".

I do believe that my ONC uses them to determine if treatment is working. I don't know if he will continue to take them, along with all of the other tumor marker and blood panel checkups.

My insurance (Anthem Blue Cross Blue Shield PPO) has paid for all of them.

Check link for more info:

http://www.questdiagnostics.com/testcenter/testguide.action?fn=TS_CellSearch.htm

SyrMom · July 2012

Thanks so much for the info ... the more education, the better!

holdontohope · July 2012

In May, my CTC result was 348.

SyrMom · September 2012

Well, an update. As I had stated previously, my CTC had gone from always 0 to 4! Although my TM were in the "normal range," they were on an upward trend. Had CT scan in July and yes, there was progression found.

So ... in my case, the rise in CTC and upward trend in TM were a sign the femara was no longer working and I was having progression!!

Heidihill · September 2012

I'm sorry to hear about your progression.

More info here, too. I got the results of my first CTC test a few weeks ago and it was 500. This is supposed to translate to more than 2 million cells in circulation. The pathology stated 60% ER+ and 15% PR+. They did not have enough blood to do the HER2 test. It was from a lab in Germany which uses a different procedure as Cellsearch. My onc did not seem to be concerned but thought it a good idea to switch to Tamoxifen from Femara as I was still ER+ after five years. He probably will want to do another test in a few months. According to the literature of the lab it's the change from one test to another that is relevant for the disease. Dormant tumors may be able to replace cells that die in circulation even after 22 years with no evidence of disease, according to one study I read. I should ask my onc about my tumor markers. All a bit confusing. The CTC tests could be telling different stories at different points of our disease.

SyrMom · September 2012

Heidihill, thanks for the info. It's interesting, to say the least. Some onc's don't run it or pay any attention to the results. However, now that I've had this experience, it sheads a new light for me, I believe.

zarovka · February 2017

Hello. Bumping this thread to see if any of you who originally posted are still using the CTC tests and how they have been used clinically. I just got a Biocept CTC test done. Zero circulating tumor cells. Yay, but I can see from this thread it is complicated to interprete.

Interested in experiences from anyone who uses this test to monitor their cancer.

Mine was not expensive, so that is one thing that has changed. $250 for CTC count plus breast panel, plus one genetic analysis. And insurance is paying. I will probably continue doing it ...

>Z<

Beatmon · February 2017

Zarovka, so glad you were zero. now how often will you ask for this test? I'm so interested in this and going to ask for it.

zarovka · February 2017

I'll probably do it quarterly to get some data on how it corresponds with scans, for me. Like TM's it is probably highly personal how it works and whether it works as a predictor of progression or a measure of drug response. It will be years, I think, before I understand what this test means for me. But I will have this disease for many years, or so they say, so eventually the test may become useful.

>Z<

Understanding CTC (circulating tumor cells) results

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