When breast cancer spreads beyond the breast and nearby lymph nodes, it’s referred to as metastatic breast cancer or stage 4 breast cancer. This advanced form can affect distant organs, most commonly the bones, lungs, liver, and brain. Understanding where it spreads, the symptoms to watch for, and ways to reduce risk can help patients and caregivers respond effectively.
According to the National Cancer Institute, bones, lungs, liver, and brain are the primary sites of metastasis. A 2020 study of over 400,000 breast cancer patients found that among those with metastatic disease, 54% developed bone metastasis, 14% had lung involvement, 10% had liver metastasis, and 1.6% experienced brain metastasis. Nearly 20% of cases involved multiple organs.
Here’s a closer look at the most common metastatic sites and their associated symptoms.
Bone Metastasis
Bones are the most frequent site for breast cancer spread. Commonly affected areas include the spine, pelvis, and thigh bones. Symptoms may include:
- Persistent or severe bone pain
- Increased risk of fractures
- Spinal cord compression
Early signs can be subtle, and bone pain might initially feel like arthritis or a muscle strain. Unlike typical aches, pain from bone metastasis persists even with rest. If you experience unusual or ongoing bone pain, consulting a doctor promptly is crucial.
Lung Metastasis
Cancer can spread to the lungs silently, sometimes discovered only during routine imaging. Symptoms may include:
- Chest pain or tightness
- Shortness of breath
- Coughing up blood
- Loss of appetite
These signs can mimic respiratory infections or preexisting lung conditions, but symptoms of lung metastasis usually persist beyond the typical duration of an infection. Learn more about lung metastasis at American Cancer Society.
Liver Metastasis
Metastasis to the liver may go unnoticed initially. Routine blood tests might reveal elevated liver enzymes, prompting further investigation. Possible symptoms include:
- Yellowing of the skin or eyes (jaundice)
- Upper right abdominal pain
- Abdominal bloating
- Itchy skin
- Swelling in the legs
- Loss of appetite
Early detection through blood work and imaging can be critical in managing liver metastasis effectively.
Brain Metastasis
Breast cancer is more likely to spread to the brain in aggressive subtypes, such as triple-negative or HER2-positive cancers. Symptoms may include:
- Persistent headaches
- Nausea or vomiting
- Seizures
- Weakness or numbness in limbs
- Memory or personality changes
- Vision, hearing, or swallowing difficulties
For more detailed information on brain metastasis, see the National Cancer Institute’s guide.
Other Possible Metastasis Sites
Although less common, breast cancer can spread to:
- Female reproductive organs (ovaries, cervix, endometrium)
- Digestive tract (esophagus, stomach, colon)
- Pancreas, kidneys, thyroid, and eyes
Diagnosing Metastatic Breast Cancer
A combination of tests is used to confirm metastatic breast cancer:
- Blood Tests: Evaluate liver function, blood cell counts, and cancer markers.
- Imaging Tests: X-rays, CT scans, MRIs, PET scans, ultrasounds, and bone scans help detect cancer spread.
- Tissue Biopsy: Confirms the presence of metastatic cells from suspicious areas.
The diagnostic approach may vary depending on the affected organ. For example, a bone scan is ideal for detecting bone metastasis, while a brain MRI is used for suspected brain involvement.
Reducing the Risk of Metastatic Breast Cancer
While it’s impossible to fully prevent cancer recurrence or metastasis, certain lifestyle habits may reduce risk:
- Maintain a healthy weight: Obesity is linked to higher recurrence rates after chemotherapy (study).
- Stay physically active: Exercise supports overall health and may enhance immune function.
- Eat a balanced diet: Focus on fruits, vegetables, whole grains, legumes, poultry, and fish. Limit red and processed meats, ultra-processed foods, and added sugars.
- Limit alcohol: Moderate consumption is defined as one drink per day for women and two drinks for men (source).
Takeaway
Metastatic breast cancer occurs when cancer spreads beyond the breast to distant organs like bones, lungs, liver, and brain. Symptoms vary based on the affected area, and early diagnosis relies on blood tests, imaging, and biopsies. Lifestyle choices such as maintaining a healthy weight, staying active, eating a nutritious diet, and limiting alcohol may help lower the risk of metastasis.
