What NETS show on Gallium scan?

Posted by mgreene @mgreene, Thu, Jan 23 11:53am

This is year 20 since the diagnosis of my first rectal carcinoid. It was not large enough to cause the carcinoid syndrome, evidently. In 2010 I had a recurrence in the area and had surgery to remove it. Again it was under the usual size where the tumor metastasizes to cause the syndrome. Within the last three years a treatment and research department has opened at one of the major hospitals in Dallas. I have not had an oncologist, ever, because I have never had any symptoms. I have consulted twice with an out-of-state specialist. I sought an appt in 2018 at the new neuroendocrine department at Baylor, hoping to learn what tests or scans could provide surveillance for me. I was rebuffed because I did not have any symptoms. I have an appt Feb 13 with a different doctor there. That doctor also questioned my need for an appointment but finally agreed to see me.

I have had a colonoscopy or flex sig annually for 20 years to watch for recurrence. Does anyone know if the Gallium68 is a good test for identifying rectal carcinoid? The Chromograinen test is not, the specialist told me (10 years ago). I suppose the specialist I see next month will know that, but I am anxious. I do not understand why it has been so difficult to get a doctor to have machines and technology look for evidence of the cancer *before* it grows enough to cause the syndrome.

Hello @mgreene,

I can understand your concern and wanting to know more about the Gallium68 scan. I also have some of the same concerns. My history with NETs is quite similar to yours except for the location. I have had three surgeries (2003, 2005 and again in 2016) but they have been all in the upper digestive tract. They have also been small and removed early on and I have had no carcinoid syndrome either. It is perplexing to me that I can have so many surgeries without appearing to have metastasis but I'm grateful for the relatively good outcome of the surgeries so far. From what I understand carcinoid syndrome is a terrible disorder to have to deal with!

I do know that certain types of NETs show up on the Gallium but I'm not sure I fully understand which type. It would be a good question to run by an oncologist. (I do not have an oncologist either but a GI doctor who specializes in NETs).

Here is a link to an article on types of surveillance for NETs. I personally found the article to be a bit complicated and I don't think it answers your question specifically, however, here is the link, https://www.carcinoid.org/for-doctors/diagnosis-and-surveillance/.

Here is another article that was written by a Mayo radiologist about the Gallium scan and the type of receptors that will appear with this scan, https://connect.mayoclinic.org/discussion/68ga-dotatate-positron-emission-tomography-pet-now-at-mayo-clinic/

Perhaps other members will be able to answer this question. I'm going to tag @tomewilson and @andre1221. Perhaps they can shed some light on their experiences and knowledge.

Liked by tsabe2

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Thank you, Teresa. Putting up roadblocks when I am trying to do anything I can to catch this cancer early causes me great stress and anxiety.

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@mgreene

Thank you, Teresa. Putting up roadblocks when I am trying to do anything I can to catch this cancer early causes me great stress and anxiety.

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I understand, @mgreene.

For most of us, cancer does result in anxiety, no doubt about that. It is probably best to get the best medical advice that you can and then try and relax about the future. This is easier said than done (I know that from experience). May I recommend a couple of Connect discussions on this topic? Here are the links to those discussions,
https://connect.mayoclinic.org/discussion/facing-cancer-recurrence-ptsd-acknowledging-mental-health/
https://connect.mayoclinic.org/discussion/the-roller-coaster-ride-of-cancer/
https://connect.mayoclinic.org/discussion/emotional-health-after-cancer/
I encourage you to read these discussions and think about the way a cancer diagnosis can affect us beyond physical health and well-being.

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Thank you, Teresa. And I am sorry you have been through three episodes and serious concerns linger.

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@amandafl and @andre1221, this might be a great topic for a guest speaker at an upcoming support group meeting – surveillance, catching NETs early, effective testing, etc.

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@colleenyoung

@amandafl and @andre1221, this might be a great topic for a guest speaker at an upcoming support group meeting – surveillance, catching NETs early, effective testing, etc.

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That’s a great idea for a topic!

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Hello @mgreene and others in this group who are interested in information about the different tests that are used for surveillance for NETs. A member recently inquired about two different tests: the 68Ga-DOTATATE and the 18F-FDG PET/CT. Here is some information that I was able to acquire on this topic.

There are certainly clinical studies about it such as this one: – Comparison of the Impact of 68Ga-DOTATATE and 18F-FDG PET/CT on Clinical Management in Patients with Neuroendocrine Tumors. https://www.ncbi.nlm.nih.gov/pubmed/27516446

While not a comparison, I found this article from the Neuroendocrine Tumor Research Foundation to be helpful in describing the different NET imaging tests, written for patients: – Imaging Tests for Neuroendocrine Tumors https://netrf.org/for-patients/nets-info/diagnostic-tests-for-neuroendocrine-cancer/imaging/

I also had the opportunity to ask a Mayo Clinic radiologist and she said that Gallium 68 (Ga-68) Dotatate PET is an excellent imaging for NET tumors. However, for some people, it does not work well. PET with Ga-68 Dotatate depends on the presence or abundance of a form of receptor on cancer cells, known as somatostatin receptor type 2. Some NET tumors may not have enough of these receptors and then the tumor would not be seen by the Ga-68 Dotatate PET. If a patient's tumor does not have somatostatin receptor type 2 or not enough of them, then the FDG-PET scan (fluorodeoxyglucose-positron emission tomography scan) would be recommended.

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