What Does Metastatic Cancer Mean?

What Does Metastatic Cancer Mean?

Sourced and Edited For Style and Content
Originally Published By The National Cancer Institute

The main reason that any cancer is so serious is its ability to spread in the body. For example, Pancreatic Cancer cells can spread by moving from the pancreas into nearby normal tissue. Cancer can also spread regionally, to nearby lymph nodes, tissues, or organs. And it can spread to distant parts of the body. When this happens, it is called metastatic cancer. For many types of cancer, it is also called Stage IV (four) cancer. The process by which cancer cells spread to other parts of the body is called metastasis.

When observed under a microscope and tested in other ways, metastatic cancer cells have features like that of the primary cancer and not like the cells in the place where the cancer is found. This is how doctors can tell that it is cancer that has spread from another part of the body.

Metastatic cancer has the same name as the primary cancer. For example, pancreatic cancer that spreads to the liver is called metastatic pancreatic cancer, not liver cancer. It is treated as Stage IV pancreatic cancer, not as liver cancer.

When a new primary cancer occurs in a person with a history of cancer, it is known as a second primary cancer. Second primary cancers are rare. Most of the time, when someone who has had cancer has cancer again, it means the first primary cancer has returned.

Cancer cells spread through the body in a series of steps. These steps include:

  1. Growing into, or invading, nearby normal tissue
  2. Moving through the walls of nearby lymph nodes or blood vessels
  3. Traveling through the lymphatic system and bloodstream to other parts of the body
  4. Stopping in small blood vessels at a distant location, invading the blood vessel walls, and moving into the surrounding tissue
  5. Growing in this tissue until a tiny tumor forms
  6. Causing new blood vessels to grow, which creates a blood supply that allows the tumor to continue growing

Most of the time, spreading cancer cells die at some point in this process. But, as long as conditions are favorable for the cancer cells at every step, some of them are able to form new tumors in other parts of the body. Metastatic cancer cells can also remain inactive at a distant site for many years before they begin to grow again, if at all.

Video: How Cancer Spreads (Metastasis)

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