Need Advice: Rising CA 15-3 with Stable PET Scan – Confused and Anxious
Hello everyone,
I’m writing to share my recent health update, and I truly hope someone who has gone through a similar experience can guide me, as I’m currently feeling confused, anxious, and struggling to make a decision.
I have hormone receptor-positive, HER2-negative breast cancer.
After three and a half years, the cancer returned and spread to my bones.
Since August 2024, I’ve been on the combination of Kisqali + Faslodex + Xgeva, and I’ve continued with this treatment until now.
My CA 15-3 tumor marker has been fluctuating. Initially, it slowly decreased from 90 to 74 over the course of about five months.
But in the past four months, it started rising gradually — from 86 and then jumping to 130 in the most recent test done a week ago.
The PET-CT scan so far shows a slow but steady decrease in uptake in the affected areas, and thankfully, no new lesions have appeared.
My doctor is puzzled by this situation and decided to run genetic mutation tests. One of them came back negative, and we’re still waiting for the rest.
He also recommended a 3 Tesla MRI for the part of my spine where the lesion is located, to see if there are any changes.
My challenge is that I have severe claustrophobia, and I can only undergo the MRI under sedation.
I keep wondering:
What if I go through this difficult scan and it shows nothing significant — would it even help?
It won’t give a full picture of the whole body anyway.
What if new spots have appeared in other areas that won’t be covered by this scan?
Will that just lead to another scan, and then another, and so on?
I would deeply appreciate hearing from anyone who has gone through something similar.
Is it possible for tumor markers like CA 15-3 to fluctuate without necessarily meaning disease progression?
This slow response to the treatment is leaving both my doctor and me uncertain and worried.
Thank you all so much ❤️❤️
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I had radiation to my spine in 2019. Ever since then, my CA15-3 has been outside of normal range with every PET Scan showing no evidence of active disease. Although not as high as yours, my 15-3 has gone up into the 50s.
In comparison, when I was first diagnosed with untreated metastatic breast cancer with a palpable breast lump, my CA15-3 was in normal range.
My thinking (unconfirmed) is that the radiation in some way caused this - those markers CAN rise with tumor die-off.
Anyway, since these tests have not shown to be accurate for me, one of my doctors suggested a Signatera test, which searches for tumor DNA in your blood. A positive result could indicate spread before it shows on scans. And a negative result might put your mind at ease.
Maybe you can ask your onc about doing Signatera or a similar circulating tumor cell test? I think Guardant has a CTC test (not the 360 that looks for mutations).
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@olma61
Thank you so much for responding to my questions 💛
My doctor has already ordered several genetic tests, including:
- Guardant360
- AKT
- PIK3CA
- ESR1
- And BRCA1/2
We’re currently waiting for the results.
He also discussed a few possible scenarios for my case and treatment options, depending on what the tests reveal.
Right now, the main challenge is getting through the MRI scan.
The hospital with the 3T MRI doesn’t offer sedation, and the one that does offer sedation only has a 1.5T MRI machine.
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@norah2024 It is difficult to make rational decisions about chemo when data that should help clarify the situation are so confusing! I think tumor marker numbers do fluctuate. After all, they just represent an approximation of the actual size/growth rate of the lesion(s).
My CA 15-3 dropped to 75 this month from around 250 earlier in the spring. In the past, for instance when liver metastasis was brewing, I saw a slow increase in that number for a while before the PET scan showed anything. It’s true that MRI is sensitive but not specific.
That means, while imaging sees lots of things we can’t always tell what they are especially if a reliable tissue sample is not possible. Keep in mind that BC usually goes to bone, liver, lung, and brain. The latter is more common for HER2+. Olma has a good suggestion regarding CTC testing.
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Norah, I read that TMs can be climbing up for 6 months before scans show signs of progression. Its great your MO is getting testing done now, since those take some time to come in, and are needed to help decide on the next protocol. An MRI is more accurate than CT, so may show any incipient mets that may be active..
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@vlnrph
Thank you so much for replying to my post.
I looked into the Signatera test but couldn’t find it here.
I’ll first look into whether the CTC test is available here in Dubai,
or if there are any alternatives to it.
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Thank you so much for your reply.
Actually, my oncologist suggested genetic testing from the very beginning of the recurrence and did send the biopsy tissue. However, the sample wasn’t sufficient, and twice they requested a blood test instead due to inadequate tissue.
This caused the whole process to be delayed for over six months.
Just a week ago, we sent new blood samples to repeat the tests, and now we’re waiting for the results.
As for the MRI, I know it’s accurate, but my fear of enclosed spaces is what’s holding me back. I haven’t yet found a center that offers mild sedation to help me complete the scan comfortably.
During my last visit, the doctor said he’s waiting for both the MRI and genetic test results before deciding on the next phase of treatment.
Adding a new medication to my current regimen feels heavy—emotionally and financially.
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@norah2024 It sounds like your biggest concern at this time is the MRI. If you can't get sedation, might it be possible to take some Valium? I don't know if this would be the thing for you, but you may ask about it and see what your doctors think.
Best wishes for good results.
Hugs, Pam 💗
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@livinglifenow
Thank you for your helpful advice, but even Valium doesn’t give me a sense of comfort during the scan.
Medications like this sometimes make me behave without focus or proper awareness of the situation, and I might move during the scan.
I’ve actually found a hospital where they agreed to give me general anesthesia during the scan, because regular sedation isn’t effective in these cases — especially since the scan can take up to two hours.
I’m currently in the process of arranging the scan, and I truly hope that my fears will ease once I get the results and discuss them with the doctor.
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@norah2024 So glad you found a place to give you what you need! 🤗 That is encouraging. Keep us posted on your scans. We are all praying for great results!
Hugs, Pam 💗
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I’m truly grateful to you and to everyone who took the time to respond and show care.
Whenever I need information or even just a bit of encouragement, I always find myself turning to this platform.
❤️❤️
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