FDG PET scan vs. 68Ga DOTATATE PET scan for neuroendocrine cancer

Hello @trixie1313

Your question is a good one and caused me to search for answers. Finding plain language information comparing relatively new diagnostic tools can be challenging. 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.

I hope this information helps guide the discussion with your oncologist, Trixie. Have they talked about receptors with you? With this information, what questions would you ask your team to help feel confident that they and you are making the best choices?

@hopeful33250
Thank you, Teresa. When I first asked my oncologist about doing the Dotatate, she pretty much said about the same thing plus she said if anything was found on the FDG PET, we would switch to the Dotatate. I think her reasoning was that since the only NET tumor so far has been in the breast, we would follow this way. I appreciate your researching this for me and feel much more reassured about the whole process.

I'm glad to hear that this information was reassuring to you, @trixie1313!

Are you scheduled for a new scan in the near future? Will you keep in touch and provide updates?

@hopeful33250 Yes, they schedule me every 6 months for the FDG PET scan and I'll be having one more 6-month mammogram and then mammograms yearly (we went with partial mastectomies). So both are due in July...fingers crossed!

I have a PNET which showed up on a GA68 DOTATATE PET. I now have a breast tumor and it did not light up on the GA 68 DOTATATE PET scan. The biopsy of the breast tumor said it was neuroendocrine focal. Could it be a NET?

Hi @vtn,

As I'm not a medical professional, I can't answer that question. It is a good question, however, to address to your oncology team. Let me know if you get an answer to that question.

How are you feeling?

@vtn
Not sure -- when they do the tumor removal and perform pathology, they will know for certain as they use a certain dye on staining for the pathology slides. I am now at yearly PET scans now as nothing further has shown in the breasts, although I have some oddities in my lungs...always an adventure.

I have some small nodules in my lungs but my NET doctor said everyone has them who have grown up in our area.

I have been getting both kinds of scans. If your initial Dodecane doesn't show much the best process is to get regular scan that may be read by the same experts. I therefore go out of town for imaging (not Dodecate) and the scans are read by a tumor review board. If/when they see changes they request the Dodecate. These are at a premium because the GA68 is available in only limited quantities.

All scans can be compromised by certain foods and because they only represent a layer at a time. However, experts can read all kinds of things into the scans invisible to folks like me.