How and Where Does Metastatic Breast Cancer Spread?

by Judi Ebbert, PhD, MPH, RN Health Writer

What is metastatic breast cancer?

Metastatic breast cancer is breast cancer that has spread beyond the breast and lymph nodes, to other parts of the body. Metastatic breast cancer is also referred to as stage IV or advanced breast cancer. Most diagnoses are made early, before the cancer has spread to the lymph nodes and other parts of the body. But it’s important to keep in mind that an estimated three in four of the women living with metastatic breast cancer were initially diagnosed with stage I-III breast cancer.

Cancer cell amongst healthy cells.

How do breast cancers start?

The human body is made of countless cells that reproduce, by splitting, to replace or repair other cells. New cells usually work like their parent cells. Sometimes, however, a new cell has an error. Not all cells with errors are bad; some are harmless, or benign. Others, however, reproduce rapidly and harm healthy cells. The offensive cells are said to be malignant because they don’t function like healthy parent cells.

Tumor in illustrated breast

How do breast cancers spread?

Cancer cells break away from the primary tumor, entering the bloodstream or the lymphatic system. As large vessels narrow, cancer cells stop traveling and lodge themselves in a new area. Then they begin dividing and moving into surrounding tissue. The cancer cells take over the new area, crowding out healthy cells and forming a new tumor. Cancer cells are insidious because the new tumor can set up its own network of blood vessels to obtain nutrients for growth and further spread.

Concerned patient being reassured by oncologist.

Where does breast cancer usually spread?

Breast cancer can spread, or metastasize, to bones, the brain, the liver, and the lungs. Metastasis to each vital organ has a unique set of symptoms. Breast cancer that has spread to bones can cause pain and fractures. Spread to the brain, it can cause headache, dizziness, and seizures. Spread to the lungs, it can cause shortness of breath. Spread to the liver, it can cause jaundice or yellowing of the skin and swelling of the abdomen.

Illustrated breast with cut away.

Can breast cancer recur at the same site?

Yes, it can recur locally or regionally. Symptoms of a local recurrence are a new lump, a firm area, pulling or swelling at the site, redness, change in the shape of the nipple, and thickening near the scar. Symptoms of regional recurrence, which includes the underarm lymph nodes and upper chest area on the same side as the initial cancer, are a lump, swelling, or numbness of the arm, pain, and problems swallowing. These symptoms warrant prompt reporting to your physician.

Female skeleton illustration.

What happens when breast cancer spreads to bone?

Breast cancer that spreads to bones can destroy normal bone. Symptoms are pain, compromised mobility, fractures, spinal cord compression, and hypercalcemia, or too much calcium in blood. Hypercalcemia can be life threatening and may cause the following symptoms: headache and fatigue; excessive thirst and urination; nausea, vomiting, and constipation; abnormal heart rhythm; muscle cramping and weakness; pain and fractures; and memory loss, depression, and irritability.

Doctor explaining treatment options to patient with tablet.

Are there treatments for bone metastases?

Yes. Multiple interventions are available for comfort and improved quality of life. Treatment decisions are dictated by whether the spread is localized or widespread and whether the type of cancer is fueled by hormones such as estrogen. The oncologist also considers prior treatments and how the patient responded to each therapy. And of course the degree of severity of symptoms as well as the patient’s overall health are important in deciding which treatment option is best.

Digital rendering of human brain.

What happens when breast cancer spreads to the brain?

When breast cancer spreads to the brain, symptoms may include headaches, seizures, nausea and vomiting, disturbances in vision, and changed behavior. Increased risk for metastases to the brain include being a younger patient; having four or more positive lymph nodes; having poorly differentiated (high grade) tumors; having HER2 positive tumors or triple negative tumors; and already having lung or liver metastases.

Woman receiving radiation therapy for brain cancer.

What treatments are available for brain metastases?

The treatment array includes radiation, surgery, and chemotherapy. The size and number of metastases will determine treatment. Chemotherapy is challenging because of the “blood brain barrier,” which protects the brain by blocking entry of bacteria and toxins, but it also prevents entry of most chemotherapies. Clinical researchers are testing promising new drugs and studying ways to penetrate the blood brain barrier.

Torso illustration with liver highlighted.

What happens when breast cancer spreads to the liver?

When metastases spread to the liver they may cause abdominal pain, a feeling of fullness, weight loss, poor appetite, and jaundice, which is a yellowing of the skin. The symptoms result from the fact that the cancer cells interfere with the normal cells’ ability to make the liver work properly. The liver does much more than many realize. The liver makes chemicals for many bodily functions, stores nutrients, and detoxifies substances in the body.

Chemotherapy drug combo

Can liver metastases be treated and if so, how?

One option, if there is disease restricted to the liver, is stereotactic radiation, which goes directly to the cancer cells. Ablation is another option, although rarely used, and it uses coldness, heat, or electrical currents to destroy the tumor. Chemotherapy, is the standard, and most common way that liver metastases are managed.

Oncologist examining lung x-ray

What happens when breast cancer spreads to the lungs?

When breast cancer spreads to the lung, it is usually as nodules or what is called “lymphangitic metastasis,” which are harder to detect. Both can cause shortness of breath. When tumors are on the outside of the lung, the pleural sac can fill with fluid, which is called a pleural effusion. To relieve shortness of breath from a pleural effusion, physicians perform thoracentesis, using local anesthesia before introducing a needle to withdraw fluid.

Doctor holding syringe of hormone therapy injection for lung cancer.

What treatments are given for lung metastases?

Usually, lung metastases are treated systemically, with chemotherapy or hormone therapy. If fluid continues to recollect in the pleural sac, the care team will perform pleurodesis, using talc or an antibiotic to seal the sac to the outside of the lung.

Healthy couple on computer.

What is being done to help people with metastatic breast cancer?

While metastatic breast cancer can’t be cured as of today, survival time has increased dramatically. Finding a cure for metastatic breast cancer is a top priority for many of the nation’s leading clinical researchers. Refer to the Susan G. Komen website to find a local affiliate, obtain educational materials, learn about additional resources, and become informed about clinical trial opportunities.

Judi Ebbert, PhD, MPH, RN
Meet Our Writer
Judi Ebbert, PhD, MPH, RN

Judi Ebbert earned her PhD at the University of South Florida’s College of Public Health. She has worked at three NCI-designated comprehensive cancer centers and is a writer/editor at Moffitt Cancer Center. Judi has great interest in chronic disease prevention and treatment, and is an advocate for equitable access to care and optimal quality of life for all people. She loves swimming, her dogs and cats, great food, art, humor, and cinematic thrillers. She’s on Twitter @judithebbert.