How Cancer Spreads
Metastatic cancer — also called stage IV or advanced cancer — occurs when cancer cells break away from the original (primary) tumor and travel through the bloodstream or lymphatic system to form new tumors in distant organs or tissues.
Common sites where cancer spreads include the lungs, liver, bones, and brain — though every cancer type has its own typical patterns of spread.
Important Things to Know
- Metastatic cancer is named after its origin, not where it spreads. Breast cancer that spreads to the lungs is still called metastatic breast cancer — not lung cancer.
- Treatment targets the original cancer type. Breast cancer cells in the lung are treated with breast cancer drugs, not lung cancer drugs.
- Metastatic cancer is generally not curable, but it is often treatable. Many patients live for years with good quality of life on treatment.
Treatment Goals
The primary goals of treating metastatic cancer are to control tumor growth, extend life, and preserve quality of life. Treatments may include systemic therapies (chemotherapy, immunotherapy, targeted therapy, hormone therapy), radiation for symptom control, and palliative care.
Living With Metastatic Cancer
A metastatic cancer diagnosis is life-changing. It is important to work with a palliative care team alongside your oncologist, connect with patient support communities, and clearly communicate your goals and values with your medical team. Many patients with metastatic cancer continue working, traveling, and spending quality time with loved ones for years after diagnosis.