- Breast cancer that's metastasized has spread to the bones, brain, lungs, or other parts of the body.
- Symptoms can depend on where the cancer is in your body, but pain, weakness, and fatigue are common.
- Treatments include hormone and radiation therapy, chemotherapy, and palliative, or supportive, care.
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Metastatic, or stage IV, breast cancer is an advanced stage of breast cancer.
It involves cancer that has spread away from the initial site of the breast to other parts of the body. About 30% of people with breast cancer develop metastatic breast cancer.
While metastatic breast cancer is a serious form of advanced cancer, treatment can still help improve survival odds.
Signs of metastatic breast cancer
General symptoms of metastatic breast cancer can include appetite loss, weight loss, and fatigue.
Other symptoms typically depend on where the cancer has spread, aka metastasized, and how much of it is in your body.
The most common sites of metastasis include the brain, liver, bones, and lungs.
1. Brain
If breast cancer spreads to your brain, you might experience:
- Headache
- Vision changes
- Speech changes
- Memory issues
Some symptoms may come on gradually, but others can be sudden, like changes in mood or personality. Abrupt changes in mood may suggest that breast cancer has spread to the brain.
2. Bones
When breast cancer metastasizes, it most commonly spreads to the bones, which you might experience as new, sudden pain in your bones.
Other potential signs include:
- Broken bones
- Weakness in your arms and legs
- Confusion, nausea and vomiting, and constipation due to excess calcium in your blood
3. Liver
Metastatic breast cancer that spreads to the liver may not always cause symptoms, but you could experience:
- Abdominal discomfort
- Weakness
- Fatigue
- Appetite loss
- Weight loss
4. Lungs
Metastasis to the lungs doesn't usually cause symptoms, though you may often feel short of breath. Other possible symptoms include:
- Chronic cough
- Pain
- Discomfort in the chest area
Getting a diagnosis
Most of the time, a diagnosis of metastatic breast cancer follows a history of breast cancer.
Though in some cases — about 5% to 10% — diagnosis doesn't happen until cancer has spread.
"Typically, that's someone with a more aggressive type of breast cancer, or maybe someone who hasn't had a mammogram for several years and doesn't necessarily do self-exams, so by the time they realize there's something wrong, it's more advanced," says Stravoula A. Otis, MD, an oncologist with Providence St. Joseph Hospital.
She adds that triple-negative breast cancer is one example of an aggressive form that comes on suddenly without prior symptoms and commonly affects younger people without a history of breast cancer.
Doctors who suspect metastatic cancer will start with a scan and confirm the diagnosis with a biopsy, which you should get back within about 7 to 10 days. Though if additional testing is needed, it can take longer.
Doctors can tell if the cancer has spread, or metastasized, by determining whether cells in other organs contain breast cancer cells.
For example, breast cancer that spreads to the lungs will consist of breast cancer cells, not lung cancer cells.
If you have a history of breast cancer and suspect it may have progressed to stage IV, your doctor will perform a new biopsy. "There's always a risk that those cells may change a little bit from the primary breast cancer," says Anna Komorowski, MD, Medical Director of Hematology and Medical Oncology at Northwell Cancer Institute at Phelps Hospital, which could affect treatment decisions.
Options for treatment
Treatment generally depends on the type of breast cancer you have, but many treatment options are oftentimes well-tolerated and can extend a person's life for many years, says Otis.
While treatment can't eliminate cancer, it can significantly boost a person's quality of life. "I have multiple patients with stage IV breast cancer working, traveling, being family members," says Komorowski.
Often, treating metastatic breast cancer is a team effort, involving palliative care professionals, oncologists, and, in some cases, surgeons — all of whom work together to use a combination of treatment options described below.
Hormone therapy
Hormone therapies work by reducing certain hormone levels in your body to keep them from attaching to cancer cells, which can cause the cancer to grow.
This is typically the first-line treatment for a type of cancer called hormone receptor-positive metastatic breast cancer. You'll need to take these medicines (in pill form or via injection) long-term, until the cancer stops responding to them.
Targeted therapy
Targeted therapy drugs are designed to target specific attributes of cancer cells. For example, they may target breast cancer cells' ability to quickly proliferate, helping to slow down cancer growth and spread.
Different targeted therapy drugs may be suitable for treating various types of metastatic breast cancer. For example, a doctor may recommend the drug Ibrance for HER2-negative, hormone-receptor-positive stage IV breast cancer cases.
Chemotherapy
Chemotherapy drugs help destroy cancer cells. In the case of metastatic breast cancer, chemotherapy is typically used alongside targeted therapy drugs for maximum effect.
Chemo drugs are the first treatment of choice for hormone receptor-negative cancers, such as triple-negative breast cancer.
It's important to note that chemotherapy is hard on the body. Possible side effects include hair loss, nausea and vomiting, increased risk of infection, fatigue, and appetite loss.
Surgery
Doctors rarely perform surgery as a first-line treatment for metastatic breast cancer, with the exception of people who receive a stage IV diagnosis when first diagnosed with breast cancer.
If that's the case for you, your treatment team may recommend removing the initial growth.
In other instances, surgery may act as a palliative measure, meaning it may help reduce pain or other symptoms but not completely eliminate them. In other words, it won't cure your cancer, but it may help make you more comfortable.
Radiation therapy
This treatment uses targeted radiation to destroy cancer cells. Radiation therapy may help reduce symptoms and control cancer growth in a specific part of the body.
In some cases, symptoms will worsen before they get better, since radiation can cause swelling and pain before tumors begin to shrink.
Other common side effects include fatigue, skin irritation, and hair loss. Radiation therapy to the brain may also cause long-term symptoms such as memory loss.
Clinical trials
There are also numerous ongoing clinical trials exploring novel treatments for advanced-stage breast cancer. If you have metastatic breast cancer, you're likely a candidate for clinical trials. Your doctor can offer more information on available clinical trials in your area.
Supportive approaches
Having the support of family and other loved ones can significantly boost your overall well-being if you have breast cancer.
Many people living with cancer also find support groups helpful.
Additionally, you may want to consider discussing palliative care options with your treatment team. Palliative care focuses on improving your quality of life and managing symptoms of your disease and the side effects of treatment.
You might also wonder, what happens when treatment no longer seems to help? This timeline is different for everyone, since it can depend on where the cancer has spread.
Your care team can offer more guidance on when it might be time to begin considering your options for hospice care and transition into discussing end-of-life support with your loved ones.
Insider's takeaway
Metastatic breast cancer is an advanced stage of breast cancer where cancer cells have metastasized, or spread from the initial cancer site.
While metastatic breast cancer is a serious diagnosis, treatment can help manage and control symptoms, allowing you to live longer.
"I think we want patients to know that it's ultimately their decision. Our job is to make sure they make an informed decision. And then our job is to support them regardless of the decision they make," says Otis.