Understanding metastatic cancer

A cancerous tumor starts in a specific spot in your body. Metastatic cancer is cancer that has spread from the part of the body where it started (its primary site or origin) to other parts of the body. When cells break away from a cancerous tumor, they can travel to other areas of the body through either the bloodstream or lymphatic channels.

If the cells travel through lymphatic channels, they can become trapped in lymph nodes – particularly those that are nearest the cancer. If the cancer cells travel through the bloodstream, they can go to any part of the body. Most often, the cancer cells break off and travel in the bloodstream. Most of these cells die, but occasionally they survive and settle into a new location, where they begin to grow and form new tumors.

Improving cancer classification can optimize therapy selection and prognosis

Identifying the primary cancer site of a metastatic cancer is important because it helps physicians select the most appropriate treatment for their patients. Metastatic cancers may be treated with chemotherapy, radiation therapy, biological therapy, hormonal therapy, surgery, cryosurgery, or a combination of these modalities.

The potential of cancer recurrence

Even when cancer has spread to a new location, it is still named after the part of the body where it started. For example, if prostate cancer spreads to the bones, it is still called prostate cancer, and if breast cancer spreads to the lungs it is still called breast cancer. When cancer comes back in a patient who appeared to be free of cancer (in remission) after treatment, it is called a recurrence. Cancer may recur as a:

• local recurrence (within or near the same organ from which it developed)
• regional recurrence (in nearby lymph nodes or in the area where lymph nodes had been removed)
• distant recurrence (involving any other part of the body not included in a local or regional recurrence)

Distant recurrence is also called metastatic recurrence. For example, the cancer might recur in distant parts of the body, such as in bones, the liver, or the lungs. This happens because some cancer cells have broken off from the original tumor, traveled elsewhere, and begun growing in these new places. Sometimes metastatic tumors have already begun to grow when the cancer is first diagnosed. In some cases, a metastasis may be discovered before the primary (original) tumor is found.

For more comprehensive information about metastatic cancer, patients should talk with their doctor and healthcare team. Additional information can also be found on the following websites:

American Cancer Society
What Is Metastatic Cancer?

National Cancer Institute
Metastatic Cancer: Questions and Answers

CancerTYPE ID Indications for Use and Limitations
CancerTYPE ID is indicated for use in tumor specimens from patients diagnosed with malignant disease and intended to aid in the classification of the tissue of origin and tumor subtype in conjunction with standard clinical and pathological assessment by a qualified physician. CancerTYPE ID is not intended to predict patient survival benefit, treatment efficacy or to distinguish between benign versus malignant lesions. Tumor types not included in the CancerTYPE ID reference database may exhibit RNA expression patterns that are similar to RNA expression patterns within the reference database.