Breast Cancer Metastasis

Metastatic Breast Cancer (MBC), also known as Stage IV or Stage 4 breast cancer, occurs when breast cancer spreads beyond the breast to other parts of the body. About 6% of women are diagnosed with breast cancer are diagnosed at Stage 4 – or de novo – from their initial diagnosis, according to the National Breast Cancer Foundation.

A Stage 4  diagnosis can happen months or even years after the initial diagnosis and treatment. Common areas where breast cancer metastasizes include the bones, liver, lungs, and brain. Symptoms of MBC vary depending on where the cancer has spread. For example, if it spreads to the bones, you might experience sudden joint pain or bone fractures. If it spreads to the lungs, symptoms might include a persistent cough or difficulty breathing.

While MBC is currently considered incurable by the medical profession of this writing in September of 2025, there are off-label and alternative treatments available to manage symptoms. Medications and other treatments vary depending on where the cancer has spread.

When breast cancer metastasizes, it most commonly spreads to the following sites, in order of likelihood:

• Bones: 60% to 75% of the time
• Lungs: 32% to 37% of the time
• Liver: 32% to 35%  of the  time
• Brain: Less common, but still significant – up to 10% of cases 
• Gastrointestinal Tract: Metastasis to this area occurs in 4% to 8% of cases
• Cutaneous(skin) Breast Cancer: 1-2% of metastasis spread to the skin, most commonly the breast skin

Unfortunately it is difficult in this stage to get a straight answer as to what exactly is going on because of the complexity of staging breast cancer. It can be a simpler process to further define terms: 

What is Locally Advanced Breast Cancer (LABC)?

LABC is breast cancer that has spread beyond the breast tissue but has not yet metastasized to distant organs. It typically involves nearby structures such as the chest wall, skin, or regional lymph nodes. Here are some key characteristics:

1. Tumor Size: The tumor is often large, typically more than 5 centimeters in diameter.
2. Involvement of Nearby Tissues: It may invade the chest wall, skin, or both, causing visible changes like swelling, redness, or ulceration.
3. Lymph Node Involvement: Cancer may spread to multiple lymph nodes in the armpit or near the collarbone.
4. Inflammatory Breast Cancer: This aggressive subtype of LABC causes the breast to appear red, swollen, and warm, often resembling an orange peel.

What is Advanced Breast Cancer?

Advanced breast cancer refers to cancer that has progressed beyond the early stages. It includes:

1. Locally Advanced Breast Cancer: Cancer has spread beyond the breast to nearby tissues, such as the chest wall or skin, but has not reached distant organs.
2. Metastatic Breast Cancer (Stage 4): Cancer has spread to distant parts of the body, such as the bones, liver, lungs, or brain.

What is Metastatic Breast Cancer?

Metastatic breast cancer, also known as Stage IV breast cancer, occurs when cancer cells spread from the breast to other parts of the body, such as the bones, liver, lungs, or brain. This process is called metastasis. Here are some key points:

1. Symptoms: Symptoms vary depending on where the cancer has spread. For example:
   • Bones: Pain, fractures, or swelling.
   • Lungs: Persistent cough, shortness of breath, or chest pain.
   • Liver: Jaundice, abdominal pain, or nausea.
   • Brain: Headaches, vision problems, or seizures.
2. Diagnosis: It is typically diagnosed through imaging tests (like CT scans, MRIs, or PET scans) and biopsies to confirm the spread.
3. Treatment: Metastatic breast cancer is not curable in 2025, however, there are treatments to help control the disease and improve symptoms. Options include Standard of Care therapies like hormone therapy, chemotherapy, targeted therapy, and immunotherapy and Off-Label & Alternative systemic treatments also 
4. Prognosis: Advances in treatment have improved survival rates, allowing some patients to manage the disease as a chronic condition.