Metastatic Breast Cancer Signs and Symptoms

Breast cancer is the second most common cancer among cisgender women in the US, according to the American Cancer Society (ACS). In general, it's treatable if detected early. But sometimes, breast cancer can spread to other parts of your body through your blood and lymphatic system and become too severe to cure (though treatment options exist). This is known as metastatic breast cancer, or stage 4 breast cancer, and it's the most advanced stage of the disease.

The most common places for breast cancer to spread, according to the ACS, are your:

• Bones
• Liver
• Lungs
• Brain

Experts aren't entirely sure why or how breast cancer spreads in this way, per the National Cancer Institute (NCI).

Metastatic breast cancer symptoms can vary significantly depending on where the cancer has spread and how far it has progressed. Below is an overview of metastatic breast cancer symptoms you may feel all over or in body parts where cancer has spread.

General Symptoms

Here are some of the more common generalized symptoms of metastatic breast cancer. A healthcare provider can help you determine if these may instead be signs of earlier-stage breast cancer or another health condition.

Fatigue

Most people with cancer experience fatigue. It can also be a sign a person's cancer has metastasized. The ACS defines fatigue as "an extreme feeling of tiredness or lack of energy, often described as being exhausted." This symptom can significantly interfere with your life, making you too tired to complete everyday activities such as eating or walking to the bathroom.

Lack of Appetite

Anorexia (which in this case means lack of appetite) is another common symptom of metastatic cancer. You may lose your appetite because certain tumors affect your hormones. Cancer symptoms like nausea and vomiting, pain, and depression may also cause a loss of appetite, according to the ACS.

If you're undergoing treatment for breast cancer you may experience a lack of appetite because of surgery or medications. Anorexia doesn't always mean your cancer has spread, per the ACS.

Extreme Weight Loss

Extreme weight loss happens because cancer starves healthy cells of nutrients. When cancer has metastasized, you can start losing weight without trying. Lack of appetite can also lead to this symptom.

Unintentionally losing more than three pounds a week is an important reason to contact a healthcare provider, as it may be a sign of a serious condition like dehydration (losing too much fluid), according to the ACS. If your cancer has metastasized, you may also experience dry skin, dizziness, thirst, or weakness.

Symptoms in Other Body Parts

Most metastatic breast cancer symptoms depend on where your cancer has spread. Someone with cancerous lesions in their bones will have a different set of symptoms than someone whose cancer has spread to their brain or liver. You may have metastatic breast cancer in multiple organs.

Here's an overview of symptoms based on the most common sites of metastatic breast cancer.

In the Bones

Up to 75% of metastatic breast cancers occur in the bone, according to a February 2020 paper published in the journal Seminars in Cancer Biology. Bone metastasis symptoms include:

• New and sudden bone pain (typically the first symptom)
• Bone pain that feels worse at night and better when you move, according to the ACS
• Pain that comes and goes at first but eventually persists
• Swelling
• Fractures or breakages that occur more easily

Bone metastasis is also the most common cause of a serious complication called hypercalcemia in people with breast cancer, according to a March 2016 paper published in the Canadian Medical Association Journal (CMAJ). This means there's too much calcium in the blood.

About 30–40% of people with breast cancer experience hypercalcemia. This condition may come without symptoms. Per MedlinePlus, it may also present with:

• Fatigue
• Frequent urination
• Muscle weakness or twitching
• Digestive symptoms

Hypercalcemia is associated with a poorer future outcome despite advancements in treatment, according to May 2019 data from the Journal of Clinical Oncology.

In the Liver

Metastatic breast cancer spreads to the liver in about 50–70% of cases, according to a March 2021 paper published in the journal Clinical & Experimental Metastasis. Liver metastasis is trickier to identify because it can occur without symptoms or the symptoms can be similar to other stomach and gastrointestinal issues. By the time a person presents with symptoms, their cancer has already progressed significantly.

Some signs that breast cancer has spread to the liver may include, per the BCRF:

• Abdominal pain
• Nausea
• Vomiting
• Bloating
• Swelling in the legs
• Jaundice (when the skin and whites of the eyes turn yellow)
• Itchy skin
• Rash

In the Lungs

As with the liver, people often don't experience symptoms of metastatic breast cancer in the lungs until the disease has progressed significantly. Lung metastasis symptoms are similar to those of an upper respiratory infection or a cold. If you have a history of breast cancer and experience the respiratory signs for more than a week, talk to your healthcare provider.

Signs breast cancer has spread to the lungs include, per an April 2018 paper published in the journal Cancer Biology & Therapy:

• Persistent coughing, sometimes with blood
• Pain
• Build-up of fluid in the lungs (pleural effusion) that can cause chest pain, shortness of breath, fever, and hiccups, per MedlinePlus

In the Brain

Brain metastasis may occur in about 15–30% of metastatic breast cancer cases, per the February 2020 paper. Symptoms can include, per the ACS:

• Headaches
• Nausea
• Vomiting
• Dizziness
• Trouble standing or walking
• In rare cases, seizures

Having some or all of these signs doesn't necessarily mean you have metastatic breast cancer, even if you have a history of breast cancer. Talk to your healthcare provider as soon as you start experiencing symptoms. They can order diagnostic procedures such as imaging tests or biopsies (examination of cells or tissues removed from the body) to figure out the cause.