The Most Common Sites of Breast Cancer Metastasis, Plus How Breast Cancer Spreads

Metastasis means spread. Breast cancer most often spreads to the bones, lungs, liver, and brain. Here’s how to navigate metastatic breast cancer with your needs in mind.

Breast cancer occurs when healthy breast cells change — or mutate — and grow. Metastatic breast cancer is also known as stage IV or advanced breast cancer.

Specifically, it means the cancer spreads to other body parts further from the breast. It’s still breast cancer because diagnosis depends on the place where the cancer formed first.

Treatment and outlook can vary, but understanding the most common sites of metastatic breast cancer can help you flag symptoms with your healthcare team.

Read on to learn the common sites for metastatic breast cancer, how metastasis happens, and ways to take care of yourself.

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Where does breast cancer spread to?

While it can be a complex disease, the goal of the cancerous cells is relatively simple: Multiply and spread from your breast area to other body parts. The National Cancer Institute reports that the most common sites to which breast cancer spreads are the:

• bones
• brain
• liver
• lungs

Additionally, early stage breast cancers may include spread from the breast to nearby lymph nodes. 

Lymph nodes

The lymph nodes are small immune system glands shaped like beans found all over the body, explains breast surgeon Michelle Shen, MD. They help protect the body from disease.

The most common cancer sites for lymph nodes are the following:

• axillary region (armpit)
• supraclavicular/infraclavicular region (around the collar bone)
• internal mammary lymph node (along the sternum or breast bone)
• cervical region (lower neck)

Cancer cells can spread to the lymph nodes as early as stage I breast cancer. Stage III breast cancers can involve the spread to 10 or more axillary lymph nodes, according to The American Cancer Society.

Bone

The bones are considered the most common site for breast cancer spread.

A 2022 study suggested that the majority of metastatic breast cancers — between 60% and 80% — occur in the bone. 

According to Roshani Patel, MD, the most common bones affected by breast cancer spread are the:

• skull
• ribs
• spine
• hip
• large bones, like arm and leg bones

Common symptoms include fractures from tumors and pain in areas like the legs and spine.

The American Cancer Society notes that doctors might diagnose bone metastasis through:

• X-rays
• positron emission tomography (PET scans)
• medical resonance imaging (MRI)
• bone scans

Lung

Research from 2018 suggests that about 60% of people with metastatic breast cancer experience it in their lungs or bones at some point.

A 2017 study found that about 31% of metastatic breast cancers occur in the lungs, while 34% spread to multiple body parts. The most common combination was the lungs and bones.

The proximity of the lungs to the breast makes these organs a common place for spread. Symptoms of spread to the lungs include:

• shortness of breath
• wheezing
• pain
• chest tightness
• coughing up blood

Pleural effusions, or “water on the lungs,” can occur when fluid builds up, potentially making breathing difficult. Doctors can drain it and perform pleurodesis, a procedure to adhere the lung to the chest wall, to try to prevent fluid buildup from happening again.

Liver

In the 2017 study mentioned above, 26% of participants experienced metastatic breast cancer in the liver, an organ responsible for helping with:

• digestion
• detoxification
• metabolism
• vitamin storage
• immunity
• blood clotting

Signs and symptoms of spread to the liver include:

• elevated liver enzymes on blood work
• fatigue
• weight loss
• jaundice
• itchy skin
• bloating
• abdominal pain

Brain

Statistics on the percentage of breast cancers that spread to the brain vary.

The 2017 study above suggested that fewer people experience spread to the brain (8.8%) than other common metastatic breast cancer sites. However, a 2023 study indicated that up to 30% of metastatic breast cancers spread to the brain. 

Research suggests the type of cancer a person has can also play a role.

For instance, a 2022 review suggested only 5% of people with cancer had spread to their brain at the time of diagnosis. However, people with triple-negative breast cancer had a higher risk, as indicated by a 2021 review.

Spread to the brain may have signs like:

• headache
• dizziness
• memory loss
• mood/behavioral changes
• balance problems
• weakness
• paralysis on one side of the body
• seizures

Less common sites of breast cancer spread

Less frequently, breast cancer can spread to other parts of the body. Metastatic breast cancer can occur in the following ways:

• bone marrow
• peritoneum, or inside wall of the abdomen
• other breast
• ovaries
• adrenal glands
• pancreas
• skin and soft tissue
• peritoneal cavity, the space in the abdomen containing the intestines, stomach, and liver

How breast cancer spreads

“Breast cancer spreads through the blood, via lymphatic vessels,” Patel said. “These lead to lymph nodes that filter the fluid and normally fight infection.”

Breast cancer then spreads directly to the next organ. For example, an advanced breast cancer may grow into the muscle and lung.

The National Cancer Institute outlines the process as follows:

1. The cancer grows into or invades neighboring tissue that does not have cancer cells.
2. The cancer travels through lymph nodes or blood vessel walls.
3. The cancer heads through the lymphatic system and bloodstream to other body parts, like the bones.
4. The cancer stops in blood vessels at the new, distant spot, enters blood vessel walls, and moves in the tissues around this body part.
5. The cancer grows into a small tumor.
6. New blood vessels grow and develop a blood supply that feeds the tumor so it can keep growing.

Why does metastatic breast cancer occur in some organs more than others?

According to Jonathan Blitzer, MD, a board certified hematologist and medical oncologist, researchers are still trying to determine why breast cancer spreads to specific body parts. However, he notes that the brain, lungs, and liver are rich in blood circulation. The bones aren’t.

The bones are “constantly subjected to local concentrations of growth factors,” Blitzer says. “Those growth factors may be sort of come-ons inviting the cancer cells to settle down.”

What is oligometastatic breast cancer?

Oligometastatic breast cancer occurs when someone has a few metastases that are usually small. For instance, breast cancer that has spread to one spot on the rib is oligometastatic.

Treating oligometastatic breast cancer is an emerging research area.

One 2021 review indicated growing support for using Stereotactic ablative radiotherapy (SABR), also known as stereotactic body radiotherapy (SBRT).

These treatments involve using high dose radiation therapies to destroy the tumor over multiple sessions. High dose radiation is targeted and limits exposure to other organs.

However, a 2022 review indicated there wasn’t definitive proof and called for more research.

Metastatic breast cancer treatment and outlook

Patel says treatments depend on:

• extent of disease
• location of spread
• type of cancer

Shen says that standard treatments for metastatic breast cancer include:

• radiation (lymph nodes, bone, brain)
• chemotherapy (lymph nodes, liver)
• hormonal/endocrine therapy (lymph nodes, liver)

Surgery may be used, but it is very rare.

“If a person is hormone sensitive, hormone blockers plus another targeted treatment will be offered that can be taken by mouth,” Patel says. “For triple negative cancer, sometimes single-agent chemotherapy may be offered depending on the extent.”

Patel adds that people with HER2-positive breast cancer might opt for targeted treatments to block specific cancer cell growth. Per the American Cancer Society, these therapies might include:

• Trastuzumab (Herceptin)
• Pertuzumab (Perjeta)
• Trastuzumab, pertuzumab, and hyaluronidase injection (Phesgo)

The outlook can vary based on where breast cancer spreads and how well the treatment works on a specific person.

A 2019 study of common sites for cancer spread indicated the 5-year survival rates for the people studied were:

• bone: 39.8%
• lung: 10.94%
• liver: 7.34%
• brain: 1.51%

Living with metastatic breast cancer

Metastatic breast cancer can take a physical and mental toll. It can be uncomfortable, decrease your sexual desire, and come with a host of questions about handling ongoing treatment — or stopping it, including end-of-life care.

The solutions and ways to manage metastatic breast cancer are not one-size-fits-all, but it helps to know your options and resources.

Lifestyle

Lifestyle habits won’t cure cancer. However, they might help you feel physically and mentally better. Shen recommends some habits to try including:

• exercise
• eating nourishing foods
• getting together with people who uplift you

Patel suggests limiting alcohol and smoking.

Sexuality

You may feel affected by bodily changes and side effects, including:

• decreased sex drive
• vaginal dryness
• fatigue
• body image issues

“People often do not feel comfortable talking to their providers about sexuality,” Patel says.

However, resources are available, like referrals to therapists for body image issues. Flagging your concerns with your care team helps them assist you.

Comfort

“Work with a rehabilitation specialist and ask for palliative care,” Patel says.” Palliative care is not end-of-life care but helps to improve quality of life with any stage of cancer.”

Palliative care might include:

• therapy to support emotional well-being
• nutritional counseling
• movement, like yoga or low impact exercises
• medication to improve treatment side effects
• mindfulness and meditation guidance and techniques
• spiritual guidance

End of life

Conversations about end-of-life care are helpful regardless of health status. 

“Nobody likes to think about it or plan for it because they feel like by planning for it, they’re hastening it,” Blitzer said. “That’s not the case. By planning for it, you’re taking a lot of weight off your family and your physicians to figure out what you would want when you can no longer explain it or make rash decisions in a crisis.”

Shen also recommends having conversations with family, friends, and your healthcare team about the progression of cancer and whether it’s responding to treatment. This can foster a shared decision making process based on what will make you most comfortable.

These conversations might include:

• ceasing treatment to attempt to eliminate tumors
• medications to relieve symptoms
• whether you’d like hospice care
• spiritual guidance
• therapy for emotional well-being
• healthcare proxy, or someone you choose to make healthcare decisions
• financial proxy, or someone you choose to make financial decisions
• ensuring the last will is updated

Frequently asked questions

Read on for answers to common questions about breast cancer metastasis.

What are the most common sites of breast metastasis?

Breast cancer most commonly spreads to the bones, lungs, liver, and brain. Breast cancer can also spread to the lymph nodes without being considered metastatic breast cancer. Spread to nearby lymph nodes can occur as early as stage one.

What’s the life expectancy for metastatic breast cancer?

It depends on the type of cancer, where it spreads, and how the treatment works for a specific person.

The 5-year survival rate for distant breast cancer was 31% between 2013 and 2019, according to American Cancer Society data. These are estimates, and people with triple-negative breast cancer have different rates.

What’s the best treatment for metastatic breast cancer?

It depends on where the cancer has spread, whether it’s positive for hormone receptors like HER-2, a person’s age, and how a treatment works for that individual. However, doctors may recommend radiation, chemotherapy, surgery, and hormonal therapies.

Importantly, breast cancer is not just physical — emotional and mental side effects are also common, and therapists, mindfulness techniques, and lifestyle habits can help. 

Takeaway

Metastatic breast cancer is also known as stage IV breast cancer. It occurs when cancer spreads to distant parts of the body.

Breast cancer most commonly spreads to the bones, lungs, liver, and brain and can spread to a combination of these body parts. Additionally, cancer can spread to the lymph nodes even in earlier stages.

Work with your healthcare team to chart the best path forward for you.