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National Cancer Institute Fact Sheet
  • Reviewed: 05/23/2011

Metastatic Cancer

Key Points

  • Metastatic cancer is cancer that has spread from the place where it first started to another place in the body.
  • Metastatic cancer has the same name and same type of cancer cells as the original cancer.
  • The most common sites of cancer metastasis are the lungs, bones, and liver.
  • Treatment for metastatic cancer usually depends on the type of cancer and the size, location, and number of metastatic tumors.

  1. What is metastatic cancer?

    Metastatic cancer is cancer that has spread from the place where it first started to another place in the body. A tumor formed by metastatic cancer cells is called a metastatic tumor or a metastasis. The process by which cancer cells spread to other parts of the body is also called metastasis.

    Metastatic cancer has the same name and the same type of cancer cells as the original, or primary, cancer. For example, breast cancer that spreads to the lungs and forms a metastatic tumor is metastatic breast cancer, not lung cancer.

    Under a microscope, metastatic cancer cells generally look the same as cells of the original cancer. Moreover, metastatic cancer cells and cells of the original cancer usually have some molecular features in common, such as the expression of certain proteins or the presence of specific chromosome changes.

    Although some types of metastatic cancer can be cured with current treatments, most cannot. Nevertheless, treatments are available for all patients with metastatic cancer. In general, the primary goal of these treatments is to control the growth of the cancer or to relieve symptoms caused by it. In some cases, metastatic cancer treatments may help prolong life. However, most people who die of cancer die of metastatic disease.

  2. Can any type of cancer form a metastatic tumor?

    Virtually all cancers, including cancers of the blood and the lymphatic system (leukemia, multiple myeloma, and lymphoma), can form metastatic tumors. Although rare, the metastasis of blood and lymphatic system cancers to the lungs, heart, central nervous system, and other tissues has been reported.

  3. Where does cancer spread?

    The most common sites of cancer metastasis are the lungs, bones, and liver. Although most cancers have the ability to spread to many different parts of the body, they usually spread to one site more often than others. The following table shows, in descending order from left to right, the three most common sites of metastasis, excluding lymph nodes, for several types of cancer:

    Cancer typeMain sites of metastasis
    BreastLungs, liver, bones
    ColonLiver, peritoneum, lungs
    KidneyLungs, liver, bones
    LungsAdrenal gland, liver, lungs

    Melanoma

    Lungs, skin/muscle, liver

    OvaryPeritoneum, liver, lungs
    PancreasLiver, lungs, peritoneum
    ProstateBones, lungs, liver
    RectumLiver, lungs, adrenal gland
    StomachLiver, peritoneum, lungs
    ThyroidLungs, liver, bones
    UterusLiver, lungs, peritoneum

  4. How does cancer spread?

    Cancer cell metastasis usually involves the following steps:

    • Local invasion: Cancer cells invade nearby normal tissue.
    • Intravasation: Cancer cells invade and move through the walls of nearby lymph vessels or blood vessels.
    • Circulation: Cancer cells move through the lymphatic system and the bloodstream to other parts of the body.

    Metastatic cancer cells invade lymph vessels and blood vessels near a tumor and migrate to other parts of the body.

    • Arrest and extravasation: Cancer cells arrest, or stop moving, in small blood vessels called capillaries at a distant location. They then invade the walls of the capillaries and migrate into the surrounding tissue.
    • Proliferation: Cancer cells multiply at the distant location to form small tumors known as micrometastases.
    • Angiogenesis: Micrometastases stimulate the growth of new blood vessels to obtain a blood supply. A blood supply is needed to obtain the oxygen and nutrients necessary for continued tumor growth.

    Because cancers of the lymphatic system or the blood system are already present inside lymph vessels, lymph nodes, or blood vessels, not all of these steps are needed for their metastasis. Also, the lymphatic system drains into the blood system at two locations in the neck.

    The ability of a cancer cell to metastasize successfully depends on its individual properties; the properties of the noncancerous cells, including immune system cells, present at the original location; and the properties of the cells it encounters in the lymphatic system or the bloodstream and at the final destination in another part of the body. Not all cancer cells, by themselves, have the ability to metastasize. In addition, the noncancerous cells at the original location may be able to block cancer cell metastasis. Furthermore, successfully reaching another location in the body does not guarantee that a metastatic tumor will form. Metastatic cancer cells can lie dormant (not grow) at a distant site for many years before they begin to grow again, if at all.

  5. Does metastatic cancer have symptoms?

    Some people with metastatic tumors do not have symptoms. Their metastases are found by x-rays or other tests.

    When symptoms of metastatic cancer occur, the type and frequency of the symptoms will depend on the size and location of the metastasis. For example, cancer that spreads to the bones is likely to cause pain and can lead to bone fractures. Cancer that spreads to the brain can cause a variety of symptoms, including headaches, seizures, and unsteadiness. Shortness of breath may be a sign of lung metastasis. Abdominal swelling or jaundice (yellowing of the skin) can indicate that cancer has spread to the liver.

    Sometimes a person’s original cancer is discovered only after a metastatic tumor causes symptoms. For example, a man whose prostate cancer has spread to the bones in his pelvis may have lower back pain (caused by the cancer in his bones) before he experiences any symptoms from the original tumor in his prostate.

  6. Can someone have a metastatic tumor without having a primary cancer?

    No. A metastatic tumor is always caused by cancer cells from another part of the body.

    In most cases, when a metastatic tumor is found first, the primary cancer can also be found. The search for the primary cancer may involve lab tests, x-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, positron emission tomography (PET) scans, and other procedures.

    However, in some patients, a metastatic tumor is diagnosed but the primary tumor cannot be found, despite extensive tests, because it either is too small or has completely regressed. The pathologist knows that the diagnosed tumor is a metastasis because the cells do not look like those of the organ or tissue in which the tumor was found. Doctors refer to the primary cancer as unknown or occult (hidden), and the patient is said to have cancer of unknown primary origin (CUP).

    Because diagnostic techniques are constantly improving, the number of cases of CUP is going down. More information about this can be found in the CUP PDQ® summary 1, which is part of NCI’s comprehensive cancer information database.

  7. If a person who was previously treated for cancer gets diagnosed with cancer a second time, is the new cancer a new primary cancer or metastatic cancer?

    The cancer may be a new primary cancer, but, in most cases, it is metastatic cancer.

  8. What treatments are used for metastatic cancer?

    Metastatic cancer may be treated with systemic therapy (chemotherapy, biological therapy, targeted therapy, hormonal therapy), local therapy (surgery, radiation therapy), or a combination of these treatments. The choice of treatment generally depends on the type of primary cancer; the size, location, and number of metastatic tumors; the patient’s age and general health; and the types of treatment the patient has had in the past. In patients with CUP, it is possible to treat the disease even though the primary cancer has not been found.

  9. Are new treatments for metastatic cancer being developed?

    Yes, researchers are studying new ways to kill or stop the growth of primary cancer cells and metastatic cancer cells, including new ways to boost the strength of immune responses against tumors. In addition, researchers are trying to find ways to disrupt individual steps in the metastatic process.

    Before any new treatment can be made widely available to patients, it must be studied in clinical trials (research studies) and found to be safe and effective in treating disease. NCI and many other organizations sponsor clinical trials that take place at hospitals, universities, medical schools, and cancer centers around the country. Clinical trials are a critical step in improving cancer care. The results of previous clinical trials have led to progress not only in the treatment of cancer but also in the detection, diagnosis, and prevention of the disease. Patients interested in taking part in a clinical trial should talk with their doctor.

Selected References
  1. Patel JK, Didolkar MS, Pickren JW, Moore RH. Metastatic pattern of malignant melanoma: a study of 216 autopsy cases. American Journal of Surgery 1978; 135(6):807–810. [PubMed Abstract] 2
  2. Disibio G, French SW. Metastatic patterns of cancer: results from a large autopsy study. Archives of Pathology & Laboratory Medicine 2008; 132(6):931–939. [PubMed Abstract] 3
  3. Talmadge JE, Fidler IJ. AACR centennial series: the biology of cancer metastasis: historical perspective. Cancer Research 2010; 70(14):5649–5669. [PubMed Abstract] 4
  4. Coghlin C, Murray GI. Current and emerging concepts in tumour metastasis. Journal of Pathology 2010; 222(1):1–15. [PubMed Abstract] 5
  5. Viadana E, Bross ID, Pickren JW. An autopsy study of the metastatic patterns of human leukemias. Oncology 1978; 35(2):87–96. [PubMed Abstract] 6
  6. Otto CM. Cardiac masses and potential cardiac “source of embolus.” In: Textbook of Clinical Echocardiography. 4th ed. Philadelphia: Elsevier, Inc., 2009.
  7. Schluterman KO, Fassas AB, Van Hemert RL, Harik SI. Multiple myeloma invasion of the central nervous system. Archives of Neurology 2004; 61(9):1423–1429. [PubMed Abstract] 7
  8. Grier J, Batchelor T. Metastatic neurologic complications of non-Hodgkin’s lymphoma. Current Oncology Reports 2005; 7(1):55–60. [PubMed Abstract] 8
  9. Aragon-Ching JB, Zujewski J. CNS metastasis: an old problem in a new guise. Clinical Cancer Research 2007; 13(6):1644–1647. [PubMed Abstract] 9
Related Resources


Glossary Terms

abdominal (ab-DAH-mih-nul)
Having to do with the abdomen, which is the part of the body between the chest and the hips that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.
adrenal gland (uh-DREE-nul...)
A small gland that makes steroid hormones, adrenaline, and noradrenaline. These hormones help control heart rate, blood pressure, and other important body functions. There are two adrenal glands, one on top of each kidney. Also called suprarenal gland.
angiogenesis (AN-jee-oh-JEH-neh-sis)
Blood vessel formation. Tumor angiogenesis is the growth of new blood vessels that tumors need to grow. This is caused by the release of chemicals by the tumor.
biological therapy (BY-oh-LAH-jih-kul THAYR-uh-pee)
Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in biological therapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological response modifier therapy, biotherapy, BRM therapy, and immunotherapy.
breast (brest)
Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.
cancer of unknown primary origin (KAN-ser ... UN-none PRY-mayr-ee OR-ih-jin)
A case in which cancer cells are found in the body, but the place where the cells first started growing (the origin or primary site) cannot be determined. Also called carcinoma of unknown primary and CUP.
capillary (KA-pih-layr-ee)
The smallest type of blood vessel. A capillary connects an arteriole (small artery) to a venule (small vein) to form a network of blood vessels in almost all parts of the body. The wall of a capillary is thin and leaky, and capillaries are involved in the exchange of fluids and gases between tissues and the blood.
central nervous system (SEN-trul NER-vus SIS-tem)
The brain and spinal cord. Also called CNS.
chemotherapy (KEE-moh-THAYR-uh-pee)
Treatment with drugs that kill cancer cells.
chromosome (KROH-muh-some)
Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes.
clinical trial (KLIH-nih-kul TRY-ul)
A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.
colon (KOH-lun)
The longest part of the large intestine, which is a tube-like organ connected to the small intestine at one end and the anus at the other. The colon removes water and some nutrients and electrolytes from partially digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus.
CT scan (… skan)
A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.
diagnosis (DY-ug-NOH-sis)
The process of identifying a disease, such as cancer, from its signs and symptoms.
diagnostic technique (DY-ug-NAH-stik tek-NEEK)
A type of method or test used to help diagnose a disease or condition. Imaging tests and tests to measure blood pressure, pulse, and temperature are examples of diagnostic techniques.
extravasation (ek-STRA-vuh-SAY-shun)
The leakage of blood, lymph, or other fluid, such as an anticancer drug, from a blood vessel or tube into the tissue around it. It is also used to describe the movement of cells out of a blood vessel into tissue during inflammation or metastasis (the spread of cancer).
hormonal therapy (hor-MOH-nul THAYR-uh-pee)
Treatment that adds, blocks, or removes hormones. For certain conditions (such as diabetes or menopause), hormones are given to adjust low hormone levels. To slow or stop the growth of certain cancers (such as prostate and breast cancer), synthetic hormones or other drugs may be given to block the body’s natural hormones. Sometimes surgery is needed to remove the gland that makes a certain hormone. Also called endocrine therapy, hormone therapy, and hormone treatment.
immune response (ih-MYOON reh-SPONTS)
The activity of the immune system against foreign substances (antigens).
immune system (ih-MYOON SIS-tem)
The complex group of organs and cells that defends the body against infections and other diseases.
intravasation (in-TRA-vuh-SAY-shun)
The movement of a cell or a foreign substance through the wall of a blood or lymph vessel into the vessel itself. In cancer, this is how cancer cells pass through a vessel wall and enter the blood or lymph systems. It is one way that cancer spreads in the body.
jaundice (JAWN-dis)
A condition in which the skin and the whites of the eyes become yellow, urine darkens, and the color of stool becomes lighter than normal. Jaundice occurs when the liver is not working properly or when a bile duct is blocked.
kidney (KID-nee)
One of a pair of organs in the abdomen. Kidneys remove waste from the blood (as urine), produce erythropoietin (a substance that stimulates red blood cell production), and play a role in blood pressure regulation.
leukemia (loo-KEE-mee-uh)
Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.
local therapy (LOH-kul THAYR-uh-pee)
Treatment that affects cells in the tumor and the area close to it.
lung (lung)
One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.
lymph node (limf node)
A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.
lymph vessel (limf ...)
A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.
lymphatic system (lim-FA-tik SIS-tem)
The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.
lymphoma (lim-FOH-muh)
Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.
melanoma (MEH-luh-NOH-muh)
A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.
micrometastasis (MY-kroh-meh-TAS-tuh-sis)
Small numbers of cancer cells that have spread from the primary tumor to other parts of the body and are too few to be picked up in a screening or diagnostic test.
MRI
A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.
multiple myeloma (MUL-tih-pul MY-eh-LOH-muh)
A type of cancer that begins in plasma cells (white blood cells that produce antibodies). Also called Kahler disease, myelomatosis, and plasma cell myeloma.
ovary (OH-vuh-ree)
One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.
pancreas (PAN-kree-us)
A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.
pathologist (puh-THAH-loh-jist)
A doctor who identifies diseases by studying cells and tissues under a microscope.
pelvis (PEL-vus)
The lower part of the abdomen, located between the hip bones.
peritoneum (PAYR-ih-toh-NEE-um)
The tissue that lines the abdominal wall and covers most of the organs in the abdomen.
PET scan (… skan)
A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called positron emission tomography scan.
prostate (PROS-tayt)
A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.
protein (PROH-teen)
A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.
radiation therapy (RAY-dee-AY-shun THAYR-uh-pee)
The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.
rectum (REK-tum)
The last several inches of the large intestine closest to the anus.
regression (reh-GREH-shun)
A decrease in the size of a tumor or in the extent of cancer in the body.
seizure (SEE-zher)
Sudden, uncontrolled body movements and changes in behavior that occur because of abnormal electrical activity in the brain. Symptoms include loss of awareness, changes in emotion, loss of muscle control, and shaking. Seizures may be caused by drugs, high fevers, head injuries, and certain diseases, such as epilepsy.
stomach (STUH-muk)
An organ that is part of the digestive system. The stomach helps digest food by mixing it with digestive juices and churning it into a thin liquid.
surgery (SER-juh-ree)
A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.
systemic therapy (sis-TEH-mik THAYR-uh-pee)
Treatment using substances that travel through the bloodstream, reaching and affecting cells all over the body.
targeted therapy (TAR-geh-ted THAYR-uh-pee)
A type of treatment that uses drugs or other substances, such as monoclonal antibodies, to identify and attack specific cancer cells. Targeted therapy may have fewer side effects than other types of cancer treatments.
thyroid (THY-royd)
A gland located beneath the larynx (voice box) that makes thyroid hormone and calcitonin. The thyroid helps regulate growth and metabolism. Also called thyroid gland.
tissue (TIH-shoo)
A group or layer of cells that work together to perform a specific function.
uterus (YOO-teh-rus)
The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a fetus develops. Also called womb.
x-ray (EX-ray)
A type of radiation used in the diagnosis and treatment of cancer and other diseases. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.

Table of Links

1http://www.cancer.gov/cancertopics/pdq/treatment/unknownprimary/Patient
2http://www.ncbi.nlm.nih.gov/pubmed/665907
3http://www.ncbi.nlm.nih.gov/pubmed/18517275
4http://www.ncbi.nlm.nih.gov/pubmed/20610625
5http://www.ncbi.nlm.nih.gov/pubmed/20681009
6http://www.ncbi.nlm.nih.gov/pubmed/274679
7http://www.ncbi.nlm.nih.gov/pubmed/15364689
8http://www.ncbi.nlm.nih.gov/pubmed/15610687
9http://www.ncbi.nlm.nih.gov/pubmed/17363516
10http://www.cancer.gov/cancertopics/factsheet/Information/clinical-trials
11http://www.cancer.gov/cancertopics/coping/advancedcancer
12http://www.cancer.gov/clinicaltrials/learningabout/treatment-trial-guide
13http://www.cancer.gov/cancertopics/wyntk/cancer
14http://www.cancer.gov/cancertopics/coping/when-cancer-returns