When cancer cells break away from the site where they first formed, they can spread (metastasize) to other parts of the body. When this happens, the cancer is considered to be metastatic, or Stage IV cancer. Cancer that has metastasized to a distant area is more difficult to treat than cancer that has not spread.
Metastasis means that cancer cells have traveled through the blood or lymph system to reach a new location. The new location is often a different organ or tissue from the original site. The cancer cells in the new tumor are usually the same type as the original cancer cells. For example, if breast cancer spreads to the lungs, it is considered metastatic lung cancer and is treated according to the type of breast cancer that started in the patient.
Cancer cells that travel through the blood or lymph system usually grow into surrounding tissues or organs. Then they can form a new tumor, which doctors call a secondary tumor. When a doctor examines the cells in the secondary tumor, they can tell if it is the same type as the cells in the original primary tumor.
Sometimes, the new cancer cells do not form a tumor. They may just spread to other parts of the body, like the bones, brain or liver. If the cancer spreads to the brain, it is usually referred to as a metastatic brain tumor. If it spreads to the liver, it is called a metastatic liver tumor.
Scientists don’t know exactly what causes cancer to spread to other parts of the body. However, they do know that some cancers spread more easily than others. They also know that certain genes are associated with metastasis.
If a patient has metastatic cancer, they will probably need to receive chemotherapy, radiation therapy or surgery. They will also need to be watched closely to make sure the cancer does not return.
The most common site for metastasis is the lungs, but cancer can also spread to other places in the body. If cancer spreads to the lungs, a person may experience symptoms such as coughing up blood, chest pain and difficulty breathing. Cancer that has spread to the lungs is considered stage IV cancer.
The most common sites for metastasis are the lungs, brain, bones and liver. Doctors can find out if a patient has metastases by doing an X-ray, CT scan or MRI. They can also use a blood test to check for metastatic cancer in the lymph nodes. If cancer has spread to the lymph nodes, it is called nodal involvement or nodal disease. In some cases, the doctor can remove the cancer metastases by performing a surgical procedure called a metastasectomy. However, in most patients, the removal of metastatic cancer will not improve their survival. The reason is that the cancer will most likely recur. This is why it is important to receive treatment as soon as possible after a diagnosis of cancer.
