Cancer that spreads from one body part to another is called metastatic cancer. If you are told that you have metastatic cancer, it means that cancer cells from one location have begun to travel through your body to another part of your body, which means that your cancer may be more difficult for doctors to treat.

In recent years, a number of treatments have been developed for people with metastatic cancer. While some of these treatments are able to eliminate the cancer, in most cases the treatments are intended to keep the disease from spreading further. They may also alleviate pain and other symptoms.

“Our entire team is focused on trying to cure Stage IV cancer, while striving for the highest quality of life for our patients,” says Kiran Turaga, MD, MPH, chief of Surgical Oncology for Yale Medicine.

Cancer that is found only in the place where it began and has not invaded nearby tissues or spread to distant parts of the body is called localized cancer. Metastatic cancer—also known as stage IV (or 4) cancer—is the name for cancer that has spread from an initial cancer site to another part of the body and proliferated there. Cancer may grow and spread to a neighboring body part, or it may travel through the bloodstream or the lymphatic system, which is part of the immune system, to a more distant site.

When cancer cells break away from the primary cancer site (the original site where it developed) and enter the bloodstream or lymphatic system, it does not mean that cancer will always develop elsewhere in the body. There may not be enough cancer cells present to develop a stronghold in a new location, or the immune system may destroy foreign cells when they’re present in distant regions.

Metastatic cancer may spread to any body part, but it spreads to these body parts most often:

• Lungs
• Bones
• Liver
• Brain

When a person is diagnosed with metastatic cancer, the cancer cells look and act like the primary cancer, so it is treated that way. If a person has prostate cancer that spreads to the bone, for example, doctors call it metastatic prostate cancer, not bone cancer, and they use treatments that are designed for prostate cancer.

Sometimes, metastatic cancer cells remain dormant for months or years after a person has been treated for their initial cancer. If a person who has previously had cancer develops a new cancer, it may actually be metastatic cancer at a different site. Doctors can tell if it is or not based on an analysis of the cells.

Occasionally, people who did not know that they had cancer are diagnosed with metastatic cancer. Doctors determine that cancer is metastatic if the biopsied cells don’t match the body part where they are removed from. Usually, doctors can find the original cancer site, which allows them to treat the cancer most appropriately; but, on occasion, they can’t determine the initial location. When this happens, it is diagnosed as cancer of unknown primary origin.

Certain metastatic cancers spread from the primary cancer site to only a few sites in the body, rather than spreading extensively to many sites around the body. These cancers are known as oligometastatic cancer (“oligo-” means “few”), and they are typically more treatable than widespread metastatic cancers. With appropriate treatment, some people with oligometastatic cancer can survive long-term, and, in some cases, the cancer can even be eliminated.

Some people with metastatic cancer may not experience any symptoms. Other people may experience symptoms such as:

• Extreme fatigue
• Unintentional weight loss
• Pain in the affected body part
• Masses (tumors) that can be seen or felt

Certain symptoms may arise when cancer spreads to specific body parts:

• Lungs—it may cause difficulty breathing
• Brain—it may cause headaches, seizures, balance issues, or dizziness
• Liver—it may cause abdominal swelling or jaundice (a yellowing of the eyes and/or skin)
• Bones—it may lead to fractures

Metastatic cancer only occurs in a person who has had cancer. People who have had cancer before can develop metastatic cancer months or years after an initial diagnosis.

When a person visits the doctor with pain, unexplained weight loss, or other symptoms, a doctor will ask about their medical history, do a physical exam, and offer tests to determine the cause of the problem.

The doctor will ask about the symptoms, as well as health history, including the type(s) of cancer that the patient has had in the past and the treatments that they received. During a physical exam, the doctor will focus on any symptoms that the person has described. They will then perform a number of tests, depending on the type of cancer that they initially had and the location of the possible current cancer.

A doctor may check for the presence of metastatic cancer with blood tests to look for tumor markers, which are substances in the blood, urine, or body tissues indicating that a specific cancer is present in a different body part. Other tests that check for the presence of cancer cells in fluid from the lungs, spine, or abdominal cavity may be ordered.

The following imaging tests may also help identify metastatic cancer:

• X-ray
• Ultrasound
• Computed tomography (CT) scan
• Magnetic resonance imaging (MRI)
• Positron emission tomography (PET) scan

When imaging tests indicate the presence of an abnormality, doctors will biopsy the site. If test results show that cancer is present and the cells are similar to the original body part and not the location of the current tumor, it is identified as metastatic cancer.

Biomarker testing (also known as tumor genetic testing, molecular testing, genomic testing, or tumor subtyping) is typically done on each tumor. These tests provide doctors with important information about each tumor that helps them determine a patient’s prognosis and guides treatment decisions.

Sometimes, doctors use imaging tests to screen patients who may be at risk of cancer recurrence. This allows them to catch possible metastatic cancer early, when it may be easier to treat.

A variety of therapies can be used to treat metastatic cancer. Doctors will prepare a personalized treatment plan for each patient based on a number of factors, including the type of primary cancer, the number and location of sites to which the cancer has metastasized, the size of the mass or masses, how fast the cancer has spread, the individual’s overall health and treatment history. In some cases, treatment aims to cure metastatic cancer, though it is often not possible to cure or eradicate the cancer. It may be possible, however, to control the cancer’s growth or relieve the symptoms it causes.

Possible treatments include:

• Chemotherapy, a type of medicine designed to kill cancer cells. It may be combined with surgery or radiation therapy.
• Radiation therapy, which destroys cancer cells by targeting them with high-energy beams
  • Stereotactic body radiation therapy (SBRT), a type of radiation therapy that precisely delivers high doses of radiation to tumors. Because SBRT targets tumors, healthy tissues are exposed to less radiation. SBRT for metastatic cancer often involves only a few treatment sessions.
• Surgery to physically remove cancerous areas
• Hormone therapy, which interferes with the body’s production of hormones, if the cancer is a type that thrives in the presence of certain hormones
• Targeted therapy, a type of precision medicine that “targets” the way that cancer cells grow and spread while sparing healthy surrounding tissue
• Immunotherapy, which uses specific drugs to bolster the patient’s immune system to fight cancer
• Radiofrequency ablation, which kills cancer cells with high-energy radio waves
• Cryoablation, which destroys cancer cells by freezing them
• Hyperthermic intraperitoneal chemotherapy (HIPEC), a surgical procedure for treating primary and metastatic cancers in the peritoneum, a membrane that lines of the abdominal cavity. Surgeons first remove all visible tumors from the abdominal cavity, then pump heated chemotherapy into the abdomen, where it bathes the inner abdominal lining and abdominal organs, killing any cancer cells that remain.
  
  For patients with cancers that have spread to the peritoneum that cannot be surgically removed, iterative HIPEC may be an option. In iterative HIPEC, chemotherapy is repetitively delivered to the abdominal cavity via small incisions. Some patients may be able to go home the same day as the procedure, while others stay in the hospital for a short period.

Other types of medication that may relieve pain and other symptoms may be used.

Different types of metastatic cancer affect people differently. In general, people with metastatic cancer have lower survival rates than those with other localized or regional cancers. Some cancers, such as oligometastatic cancers, can be well-controlled with treatment, and people may be able to live for many years while managing their condition. In some cases, the cancer can even be eliminated.

Sometimes, however, there are no treatments that will help keep the cancer under control. In addition to other treatments, palliative care, which aims to optimize quality of life in part by managing symptoms and side effects, is often recommended for people with metastatic cancer. When metastatic cancer can no longer be controlled with treatment, it may be time to think about and discuss comfort measures (to minimize pain and distress) and what end-of-life care will look like in the weeks or months that remain.

“Our program at Yale is among the very few in the country that seamlessly integrates research, clinical excellence, and kindness to provide the most compassionate and effective care for patients with metastases,” says Dr. Turaga. “Each of us comes to work with a single-minded purpose of curing cancer and alleviating the suffering that it causes for patients, their friends, and families.”