Metastatic Cancer (Stage 4 Cancer)

How cancer spreads

Cancer cells can break away from the primary tumor and travel:

• through the bloodstream to distant organs
• through the lymphatic system to lymph nodes and beyond
• directly across body cavities, such as the lining of the abdomen or chest

Most cells that escape die, but some survive and grow into new tumors (metastases). Metastases may be found at the same time as the primary cancer or appear years after treatment.

Where common cancers spread

Symptoms by site

Some people have no symptoms, and metastases are found on scans.

• Bone metastases: bone pain, fractures with little trauma, high calcium, and spinal cord compression
• Liver metastases: pain under the right ribs, swollen belly, yellow skin, loss of appetite
• Lung metastases: cough, shortness of breath, fluid around the lungs (malignant pleural effusion)
• Brain metastases: headaches, seizures, weakness, confusion, vision or speech changes
• Lymph nodes: painless swelling
• Peritoneum: bloating, fluid in the belly (ascites), bowel obstruction

General symptoms include fatigue, weight loss and loss of appetite (cachexia).

Diagnosis and staging

• imaging: CT scans, MRI, PET-CT and bone scans to find where cancer has spread
• biopsy of a metastasis to confirm it and test its features, which can differ from the original tumor
• biomarker and genetic testing of the tumor (for example HER2, hormone receptors, EGFR, ALK, BRAF, KRAS, MSI, PD-L1) to guide targeted therapy and immunotherapy
• blood tests, including tumor markers for some cancers, and liver, kidney and bone chemistry

In the TNM staging system, the "M1" category means distant metastasis, which usually defines stage 4.

Treatment

Treatment is based on the type of cancer, its biology, where it has spread, previous treatments and your goals and health.

Whole-body (systemic) treatments

• hormone therapy for hormone-sensitive breast and prostate cancers
• chemotherapy
• targeted therapy against specific mutations or proteins
• immunotherapy (checkpoint inhibitors), which has transformed outcomes in melanoma, lung, kidney and other cancers
• antibody-drug conjugates that deliver chemotherapy directly to cancer cells

Local treatments

• radiation therapy for painful bone metastases, brain metastases and bleeding
• stereotactic radiation or surgery to remove a small number of metastases (oligometastatic disease), which can lead to long-term control in selected cancers such as colorectal cancer with liver metastases
• ablation of liver or lung metastases

Supportive and palliative care

Palliative care focuses on symptom relief and quality of life and can be given alongside active cancer treatment from diagnosis onward. It includes pain control, managing breathlessness, nausea and fatigue, emotional and spiritual support, and planning for the future. Bone-strengthening medicines reduce fractures from bone metastases.

Outlook

Outlook varies enormously:

• Some metastatic cancers, such as testicular cancer and some lymphomas, can be cured.
• Others, such as hormone-positive breast cancer and some prostate cancers, may be controlled for many years.
• Cancers with targetable mutations or good responses to immunotherapy can have long-term control.
• Some, such as metastatic pancreatic cancer, remain difficult to treat.

Your oncology team can give the most accurate picture for your situation.

Living with metastatic cancer

• ask about treatment goals, expected benefits and side effects of each option
• ask about clinical trials
• involve a palliative care team early
• make an advance care plan and name a health care proxy
• seek emotional support for yourself and family. Caregiver stress is common
• hospice care is available when the focus shifts fully to comfort

Frequently asked questions

What does metastatic cancer mean?

Metastatic cancer is cancer that has spread from its original site to distant parts of the body, such as the bones, liver, lungs or brain. It is usually called stage 4. The cancer keeps the name of its origin, for example metastatic breast cancer in the liver.

Can metastatic cancer be cured?

Usually not, though there are exceptions such as testicular cancer and some lymphomas, and some people with a small number of metastases can be cured with surgery or radiation. For most, treatment aims to control the cancer and maintain quality of life for as long as possible.

What is the life expectancy with stage 4 cancer?

It varies widely by cancer type, where it has spread, tumor biology and response to treatment. Some people live for months, while many with breast, prostate, kidney cancer or melanoma treated with modern therapies live for years. Your oncologist can give personal estimates.

What are the symptoms of metastatic cancer?

Symptoms depend on where cancer has spread: bone pain and fractures, cough and breathlessness, belly swelling and jaundice, headaches and seizures. General symptoms include fatigue, weight loss and poor appetite. Some people have no symptoms.

Is palliative care the same as hospice?

No. Palliative care focuses on relieving symptoms and stress and can be given at any stage, alongside treatments aimed at controlling cancer. Hospice is a type of palliative care for people who are expected to live months rather than years and have chosen to focus fully on comfort.