Elevated CA 15-3, Stage 3, without metastases

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!

Comments

  • obsolete
    obsolete Posts: 428

    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

  • 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
    ghf2025 Posts: 2

    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
    moderators Posts: 10,007

    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