Imaging
CT, PET, MRI, or bone scans may show where cancer is in the body and help your team follow changes over time.
UNDERSTANDING YOUR DIAGNOSIS
Start with the facts.
Move forward with your voice.
A metastatic breast cancer diagnosis can bring a lot of new words, tests, and decisions. You do not have to learn everything at once.
This guide explains the basics so you can better understand your results and take part in conversations about your care.
01
WHAT METASTATIC MEANS
It started in the breast.
It has spread somewhere else.
Metastatic breast cancer—also called stage 4 breast cancer—means breast cancer cells have traveled to another part of the body.
Common places include the bones, liver, lungs, or brain. Even when breast cancer is found in a bone or another organ, it is still breast cancer. It is named for where it started, not where it spread.
HOW YOUR CARE TEAM LEARNS MORE
Your diagnosis is built from several pieces.
No single test tells the whole story. Your team brings results together to understand where the cancer is, what it is like, and which treatments may help.
Biopsy
A small tissue sample can confirm that a spot is breast cancer and provide cells for important lab tests.
Pathology
A pathology report describes the cancer cells, including hormone receptors and HER2 status.
Blood tests
Blood work can check your overall health and how organs are working. Some blood tests may also look for tumor changes.
YOUR BREAST CANCER SUBTYPE
Why those plus and minus signs matter.
A subtype describes features found on or inside the cancer cells. Your subtype helps your care team narrow down which treatments are more likely to work.
HORMONE RECEPTOR–POSITIVE
The cancer uses hormones as fuel.
The cells have estrogen receptors (ER+) or progesterone receptors (PR+), or both. Hormone therapy can block that fuel. It is often paired with a targeted medicine.
This may open the door to:Hormone therapyCDK4/6 inhibitorsOther targeted treatments
HER2-POSITIVE
The cells make extra HER2 protein.
HER2 helps cells grow. When cancer cells make too much of it, HER2-targeted treatments can block that signal. A cancer can be both HR+ and HER2+.
This may open the door to:HER2-targeted medicinesAntibody-drug conjugatesChemotherapy combinations
TRIPLE-NEGATIVE
The three main markers are negative.
The cells do not have ER or PR and do not make high levels of HER2. Hormone and HER2 medicines are not a match, but other options are available.
This may open the door to:ChemotherapyImmunotherapy for some tumorsAntibody-drug conjugates
Your subtype can change.
Results from the metastatic tumor may differ from the first breast tumor. Ask whether a new biopsy or repeat biomarker testing could help guide your current care.
BIOMARKER TESTING
Tests can reveal more treatment possibilities.
A biomarker is a sign found in cancer cells, genes, or blood. It can help predict whether a certain treatment may work. Some tests look at one marker. Others look at many genes at once.
Hormone receptors
Show whether estrogen or progesterone may be helping the cancer grow.
HER2 protein or gene
Shows whether HER2-targeted treatments may be an option. Reports may also describe HER2-low or HER2-ultralow disease.
Inherited and tumor gene changes
Some BRCA changes may make PARP inhibitor medicines an option. A blood or saliva test can check for inherited changes.
Changes that may appear over time
These changes can help guide certain targeted treatments for HR-positive, HER2-negative mBC.
Immune-system marker
For some people with triple-negative mBC, this test can help show whether immunotherapy may be useful.
Two kinds of genetic testing
Inherited testing looks for a gene change you were born with. Tumor testing looks for changes inside the cancer. They answer different questions, and your team may recommend one or both.
WHAT GUIDES YOUR CARE
Your test results matter.
So do your priorities.
Your care plan may be shaped by your subtype, biomarker results, where the cancer has spread, treatments you have already received, other health conditions, side effects, and what matters most in your daily life.
Treatment for mBC often focuses on controlling the cancer, easing symptoms, helping you live longer, and protecting your quality of life. Plans may change as the cancer changes or as new options become available.
QUESTIONS FOR YOUR NEXT VISIT
You have a right to understand your care.
Take a screenshot, print this list, or ask someone you trust to take notes.
- 01What is my current breast cancer subtype?
- 02Were ER, PR, and HER2 tested on the metastatic tumor?
- 03Could another biopsy or a liquid biopsy help?
- 04Which biomarker or genetic tests have I had—and what did they show?
- 05How do these results affect my treatment options?
- 06What is the goal of the treatment you recommend?
- 07How will we know whether the treatment is working?
- 08Are there clinical trials that match my subtype or biomarkers?
This page uses patient information from the National Cancer Institute and American Cancer Society. It is for education and does not replace advice from your oncology team.