Elevated CA 15-3, Stage 3, without metastases

ghf2025

Hello everyone,

July 2024 – Diagnosis: breast cancer ER+ / HER2 negative, with lymph node involvement, no metastases, stage IIIA. I had a CT, MRI, and PET-CT before starting chemotherapy.

August 2024 – I started chemotherapy, but before that I measured CA 15-3, which was elevated at 74 U/ml. It increased up to 92 halfway through the treatment, but returned to normal limits after I finished chemotherapy (24 U/ml).

After chemo, I had surgery, and before starting radiotherapy I checked it again – it was 21 U/ml. The next measurement was done 6 weeks after radiotherapy, before starting the first cycle of Ribociclib, and CA 15-3 had risen slightly to 24 U/ml.

I started Ribociclib preventively, because I have a high risk of recurrence. I tested the marker again after the first cycle of Ribociclib, when it had increased to 29, and again after the second cycle of Ribociclib, when it rose to 34.6 U/ml.

These increases make me quite anxious.

Are there other people in stage III who have experienced a rise in tumor marker after starting Ribociclib (Kisquali) or Abemaciclib (Verzenio), without this being associated with the appearance of metastases?

Wishing you all good health!

obsolete

Bumping for those with same…

Hello, sorry for your experiences. Naturally, not meeting expectations can and will cause anxiety. Read below. Wishing you peace and comfort. Hugs!

"WHAT LEVEL OF CA 15-3 INDICATES CANCER?

A single elevated reading is not definitive for diagnosis; it is interpreted alongside other clinical information, imaging studies, and patient history.

"Gynecological conditions can also contribute to elevated CA 15-3 levels. These include ovarian cysts, endometriosis and pelvic inflammatory disease."

"The “normal” reference range for CA 15-3 levels is generally less than 30 Units per milliliter (U/mL). Note that this upper limit can vary slightly between different laboratories and the specific testing kits they use. Results from different labs should not be directly compared."

"An elevated CA 15-3 level does not automatically signify the presence of cancer. Many non-cancerous conditions can also lead to increased CA 15-3 levels."

https://biologyinsights.com/what-level-of-ca-15-3-indicates-cancer/

CA15-3 (CANCER ANTIGEN 15-3)

"CA 15-3 is elevated in about 30% of women with localised breast cancer and in about 75%... that has metastasised."

"25% to 30% of individuals with advanced breast cancer have tumours that do not produce CA 15-3."

"Levels of CA 15-3 are not usually taken immediately after breast cancer treatment begins because there have been instances of temporary increases in CA 15-3 that do not match with the patient’s progress."

https://www.pathologytestsexplained.org.au/ptests-pro.php?q=CA15-3+%28Cancer+antigen+15-3%29

pghmomma412

I am going though this now and would love hear any updates.

I was diagnosed 7/2024 with Stage 3A, ER/PR+Her2- bc. My CA 15.3 was 7 after surgery and before chemo. Finished chemo in Feb 2025, finished radiation 6/25 and starting Kisquali in July. My CA 15-3 was 9 after cycle 1 and now my CA 15.3 is at 15 after cycle 4.

ghf2025

Dear Pghmomma412,

Here is my update.

My CA15-3 marker increased to 38.5 U/ml and stayed around this values when I had 400 mg Ribociclib dose.

I tested an intake of 200 mg Ribociclib for 2 cicles and the CA15-3 marker dropped to 30.5 U/ml.
When I went back on the 400 mg Ribociclib daily dose the marker increased again to 38.7 U/ml.

I had 10 Ribociclib circles so far.

The CT Scan is clear.

I hope this increase above normal for CA 15-3 marker is just a reaction to Ribociclib treatment.

How is your treatment going? I hope to hear good news from you.

And I hope to hear about some others experience with this marker.

moderators

Hi @ghf2025! Thank you so much for coming back and sharing this update. We really appreciate you taking the time to do that. It’s helpful to see how things have evolved for you, especially alongside a clear CT scan.

We hope you’re continuing to do well, and we also hope others with similar experiences around CA 15-3 and Ribociclib will see your post and join the conversation.

Best wishes,
From the Mods

cipgirl89

I am experiecing something similar to you, @ghf2025 . Right after chemo, dxm, radiation, my CA 15-3 was 18 this January. I started my first round of Kisqali in March (high risk) and it went up to 19, then 23 in April. Then 26 in August ( a few weeks post breast reconstruction) and 28 in September (a few days ago). My CEA has stayed / gone down. I had a scan in July to see and it was clear. No one really mentioned the medicine being a culprit…they say "maybe, but we don't really know". Any others have similar situations?

moderators

Welcome, @cipgirl89 . We can understand why seeing CA 15-3 gradually rise would get your attention, especially after everything you’ve already been through.

One thing that can make tumor markers so frustrating is that it’s really about the trend over time and the bigger picture, rather than any one number. Your oncology team is in the best position to interpret that alongside your scans and everything else they know about you.

Breastcancer.org has more information about tumor markers and biomarker testing that may be helpful.

Hopefully others taking Kisqali will jump in and share what their own CA 15-3 numbers have done. And if you’d ever like to talk with others going through treatment in real time, you’re very welcome to join one of our free Virtual Support Groups on Zoom.

Please keep us posted on how you’re doing. ❤️

ghf2025

I don’t know if anyone else has done this experiment, but the CA 15-3 marker scared me so much that I started checking it weekly. I wanted to see whether it was influenced by Ribociclib treatment.

I found that on day 14 of treatment, it goes down to around 32 U/mL, while on day 28, it goes back up to around 38 U/mL. This has happened consistently over the last 8 cycles.

When I had a bad cold or flu, for example, it usually went higher, up to 41 U/mL. But during the next Ribociclib cycle, it returned to the same pattern: on day 14, it went down to 32–33 U/mL, and on day 28, it went back up to 37–38 U/mL.

Also, when I tested a dose of 200 mg of Ribociclib for 2 cycles, the CA 15-3 marker dropped even further, to 29.5–30.5 U/mL on day 14.

Has anyone else noticed a similar correlation?

cipgirl89

my ca 15-3 unfortunately hasn't gone down, nor did we test frequently enough to know if my off-cycle periods impacted. but I did notice that during a 4 month period where i had multiple pause due to ANC and surgery, my number only went up by 3 points. I'm spiraling as you could imagine.