Prompt follow-up

Breast cancerHER2-positive breast cancer

“HER2-positive” means the cancer has higher than normal levels of the HER2 protein (or extra copies of the related gene) by the tests your lab uses. Several anti-HER2 treatments are a standard part of care in many people when appropriate. Some HER2-positive cancers are also hormone receptor–positive, so endocrine therapy may also be discussed depending on stage and receptor status.

This page is for education only. It does not replace a visit with a qualified clinician. Your care team’s advice for you may differ from what you read here.

Preview — not yet published

This page is in editorial and medical review. Content below is a scaffold — treat it as a preview, not guidance.

Orientation

What to do next

A simple timeline many people find useful — your team’s pace may be faster or slower.

  1. Today

    Confirm you have a clear, final HER2 test result; in borderline cases, some labs recheck with another test.

  2. This week

    If invasive HER2+ disease, your team will connect surgery, systemic therapy, and often radiation, when indicated, in a time sequence that matches your case.

  3. Over the next few weeks

    For early-stage disease, anti-HER2 therapy is often limited to a set duration when used with other treatments; in metastatic settings, the plan is usually ongoing with breaks as needed, depending on your situation.

Decisions ahead

Results that often matter for next steps

  • HER2 status

    Positive (by IHC, FISH, and/or other approved methods in your system)

    HER2 positivity is what makes anti-HER2 drugs relevant when your team recommends them, alongside hormone therapy and/or chemo as appropriate for your subtype.

    Ask: How was HER2 tested, and is the result final?

  • Hormone receptors (ER/PR)

    Positive, negative, or both matter if positive

    Some people have HER2-positive cancers that are also HR-positive. In that situation, endocrine therapy may be part of the plan after or alongside other treatment, depending on stage and your team’s recommendations.

    Ask: Am I also ER/PR-positive, and if so, how do hormone therapy and anti-HER2 fit together?

  • Stage and nodes

    Early vs metastatic setting

    In early disease, the goal is often to treat the breast and any involved nodes, then use systemic therapy to reduce risk of return. In metastatic disease, treatment aims to control disease, manage symptoms, and use trials if appropriate.

    Ask: What stage is my disease, and do you recommend treatment before or after surgery?

Treatment overview

Treatment by situation — not personal advice

Your care team tailors a plan to your specific stage, other health conditions, and preferences.

  • Early invasive HER2+

    Common options
    Surgery, chemotherapy plus anti-HER2 therapy in many (not all) situations, and radiation and/or endocrine therapy as indicated by receptor status and other factors.
    Why this may come up
    Anti-HER2 treatment has changed outcomes for many people with high-risk early HER2+ disease, but the exact plan must match your own staging and team recommendations.
    Questions to ask
    What regimen are you suggesting, and for how long, for the anti-HER2 and chemo parts?

  • Metastatic HER2+

    Common options
    Sequential anti-HER2–based regimens, sometimes with other agents; clinical trials; local treatment in select situations. Goals of care and quality of life are central.
    Why this may come up
    Multiple lines of standard therapy and trials can exist. Your team will also watch for side effects, especially with heart and infusion reactions when relevant.
    Questions to ask
    If one line stops working, what is the usual next line in my situation, and when is a trial reasonable?

Research

Clinical trials and when to ask (HER2+)

Studies in HER2-positive disease have historically moved standard care forward quickly. Trials may be an option in early (often high-risk) settings, at first metastatic line, or after progression, depending on eligibility. Ask your oncologist and trial staff what would change if you enroll, what the consent process includes, and which standard off-study regimens you could access now.

When to seek care

Emergency, prompt, and routine

Call 911 or seek emergency care if

  • Severe allergic reaction to treatment (e.g. throat tightness) — follow your clinic’s instructions and seek emergency help if needed

Call your care team promptly if

  • New or worsening shortness of breath, leg swelling, or weight gain in days during anti-HER2 therapy — could be a heart or fluid problem; call the same day
  • Fever with low counts during treatment — call by your team’s rules

Bring this up at your next visit if

  • Whether cardiac monitoring is needed for your specific anti-HER2 therapy
  • Dose delays or side effects to watch for on your specific regimen

For your next visit

Questions to ask your care team

  • Is my cancer HER2-low or HER2-positive, and by which test? Does that change which drugs are options?

  • For early-stage disease, how long is anti-HER2 treatment planned, and is chemotherapy part of the plan for me?

  • For metastatic disease, what is our first-line plan and the usual next steps if the cancer grows?

  • Is there a clinical trial I should know about for my line of therapy and receptor profile?

Review, sources, and disclaimer

How this page was reviewed

Medical review

Pending medical review. This page will list the reviewing clinician and review date before publication.

Content version 0.1

This page is educational, not medical advice. Talk with your care team about decisions that apply to you. If something feels urgent, contact your doctor — or, for emergencies, call your local emergency number.