Metastasis (Metastatic Cancer): Definition, Biology & Types

Metastasis (Metastatic Cancer)
Metastatic cancer occurs when cancer cells break off from the original tumor, enter your bloodstream or lymph system and spread to other areas of your body. Most metastatic cancers are manageable, but not curable. Treatment can ease your symptoms, slow cancer growth and improve your quality of life.
Overview
What is metastatic cancer?
Metastatic cancer refers to cancer that has spread beyond the point of origin to other, distant areas of the body. To fully understand metastatic cancer, we’ll first define metastasis:
Metastasis is a word used to describe the spread of cancer. Unlike normal cells, cancer cells have the ability to grow outside of the place in your body where they originated. When this happens, it’s called metastatic cancer, advanced cancer or Stage IV cancer. Nearly all types of cancer have the potential to metastasize, but whether they do depends on a number of factors. Metastatic tumors (metastases) can occur in three ways:
What are the most common sites of metastatic cancer?
The most common sites for cancers to metastasize include the lungs, liver, bones and brain. Other places include the adrenal gland, lymph nodes, skin and other organs.
Sometimes, a metastasis will be found without a known primary cancer (point of origin). In this situation, your healthcare provider will search extensively for the primary cancer source. If none can be found, it’s called cancer of unknown primary (CUPS).
Symptoms and Causes
What are the symptoms of metastatic cancer?
Some people will have minimal or no symptoms of metastatic cancer. If symptoms are present, they’re based on the location of the metastasis.
Bone metastasis
Bone metastasis may or may not cause pain. The first sign of bone metastasis is bone breakage after a minor injury or no injury. Severe back pain accompanied by leg numbness or difficulty with bowel or bladder control must be evaluated immediately.
Brain metastasis
If a tumor has metastasized to the brain, symptoms may include headache, dizziness, visual problems, speech problems, nausea, difficulty walking or confusion.
Liver metastasis
Liver metastasis can cause pain, weight loss, nausea, loss of appetite, abdominal fluid (ascites) or jaundice (yellowing of the skin and the whites of eyes).
What causes metastatic cancer and how does it spread?
Metastatic cancer occurs when cancer cells break off from the original tumor and spread to other parts of the body via bloodstream or lymph vessels.
Diagnosis and Tests
What tests will my healthcare provider use to diagnose metastatic cancer?
There is no standard test to check for metastasis. Your healthcare provider will order tests based on the type of cancer you have and the symptoms you’ve developed.
Blood tests
Routine blood tests can tell your provider if your liver enzymes are elevated. This could indicate liver metastasis. In many cases, however, these blood test results are normal, even in the presence of advanced cancer.
Tumor markers
Some cancers have tumor markers that can be helpful in monitoring cancer after diagnosis. If tumor marker levels increase, it could mean that your cancer is advancing. Some examples are:
There are several tumor markers that are less specific, and therefore, not used as a tool for diagnosing metastasis.
Imaging
There are many tests that “take pictures” of the inside of your body. Appropriate tests depend on the symptoms and the type of cancer. Imaging tests may include:
Ultrasound is one way to evaluate the abdomen and identify any tumors. It can detect fluid in the abdomen and can show the difference between fluid-filled cysts and solid masses.
CT scan (computed tomography) can detect abnormalities in the head, neck, chest, abdomen and pelvis. It can also identify tumors in the lungs, liver or lymph nodes.
A bone scan is done with a radioactive tracer that attaches to damaged bones and shows as a “hot spot” on the scan. It’s most useful for evaluating the whole body for evidence of cancer-related bone damage. If your provider suspects a fracture, they may take additional X-rays to determine the extent of the damage.
PET scan (positron emission tomography) works to identify abnormalities anywhere in the body. It uses a special dye containing radioactive tracers that "light up” problematic areas.
The results of these tests may not provide definitive answers. In some cases, your healthcare provider may also take a biopsy (a small tissue sample) of the suspected metastatic tumor.
Management and Treatment
How is metastatic cancer treated?
Metastasis is treated based on the original site of cancer. For example, if a person has breast cancer and cancer spreads to their liver, it is still treated the same way as breast cancer. This is because the cancer cells themselves haven’t changed — they’re just living in a new place.
In some cases, your provider may treat metastatic tumors in specific ways.
Bone metastasis
If bone tumors aren’t causing pain, your provider may monitor your situation or recommend drug therapy. If there is pain or if the bone tissue is weak, your provider may recommend radiation therapy.
Brain metastasis
Lung metastasis
The treatment of metastatic tumors in the lung depends on the specific situation. In most cases, it will be treated with the same drugs as the primary cancer (where cancer originated). If fluid builds up around the lungs, a procedure called thoracentesis can make breathing easier.
Liver metastasis
There are a number of ways to treat metastatic tumors of the liver. The appropriate treatment depends on the type of primary cancer and the number of metastatic tumors. In many cases, your provider will treat liver metastases the same way they treated the primary tumor. If the disease hasn’t spread too far, then your provider may recommend surgery or radiofrequency ablation (RFA). Organ transplant is generally not an option for metastatic disease.
Prevention
Can I prevent metastatic cancer?
When cancer is detected at an earlier stage, systemic treatments given in addition to surgery (often called adjuvant or neoadjuvant treatment) may be recommended to reduce the likelihood of developing metastasis. These treatments may include chemotherapy, hormonal treatments or immunotherapy. Research is ongoing in these areas and experts are trying to find ways to slow, stop or prevent the spread of cancer cells.
Outlook / Prognosis
What can I expect if I have metastatic cancer?
Your healthcare provider will work closely with you. They’ll monitor your symptoms and find treatments to ease them. You’ll probably have many medical visits and will need to make important decisions regarding your overall health.
Is metastatic cancer curable?
In most cases, metastatic cancer is not curable. However, treatment can slow growth and ease many of the associated symptoms. It’s possible to live for several years with some types of cancer, even after it has metastasized. Some types of metastatic cancer are potentially curable, including melanoma and colon cancer.
What is the metastatic cancer survival rate?
The five-year survival rate of metastatic cancer depends on the type of cancer you have. For example, the five-year survival rate for metastatic lung cancer is 7%. This means that 7% of people diagnosed with metastatic lung cancer are still alive five years later. Meanwhile, the five-year survival rate of metastatic breast cancer is 28% for women and 22% for men.
Living With
How do I take care of myself?
Being diagnosed with metastatic cancer comes with many challenges. These challenges vary from person to person, but you might:
Feel sad, angry or hopeless.
Worry that treatment won’t work and that your cancer will get worse quickly.
Get tired of going to so many appointments and making so many important decisions.
Need help with daily routines.
Feel frustrated about the cost of your treatment.
Talking with a counselor or social worker can help you cope with these complicated emotions. Managing stress is also an important aspect of self-care. Practice meditation, mindfulness or find other ways to reduce stress and anxiety.
When should I see my healthcare provider?
If you have metastatic cancer and you develop new symptoms, call your healthcare provider right away. They can adjust your treatment to meet your specific needs.
What questions should I ask my doctor?
Learning about your condition can empower you to make informed decisions. Some people only want to know the basics, while other people prefer to know every detail about their prognosis. Here are some questions you may want to ask your healthcare provider:
Are there things I can do to improve my prognosis?
What are my treatment options?
Are there clinical trial options that might be appropriate for me?
Will palliative care continue even if I stop cancer treatments?
How often will I need to schedule follow-up appointments?
Do I need to consider hospice care?
Should I choose a person to make medical decisions for me when I’m unable to make them for myself?
What legal documents should I have in place?
What resources are available to help me cope with my prognosis?
A note from Cleveland Clinic
A metastatic cancer diagnosis is one of the scariest things you may ever encounter. If you or a family member has been diagnosed with advanced cancer, you’re probably feeling a lot of complicated emotions. While most metastatic cancers aren’t curable, there are treatments that can ease your symptoms and prolong your life. Ask your healthcare provider for resources and consider joining a local support group. Talking with other people who are going through the same thing can be healing during this emotionally difficult time.