Metastases: what they are, how they are diagnosed and how they manifest

The word "metastases" sounds heavy in a report or in a conversation with a doctor, and it almost always raises many questions. Below is a calm explanation: what it is, how it forms, how it is diagnosed and what signs it causes.

What metastases are and how they form

Metastases are secondary foci of tumor growth. They appear when cells of a malignant tumor leave the place where it originated and form new tumors in other tissues. The formation of metastases is the main criterion of a tumor's malignancy.

The cell's journey consists of stages: it grows into neighboring tissues, passes through the wall of the nearest lymph node or vessel, is carried with the flow of lymph and blood, stops in a small vessel far from the primary node, exits into the surrounding tissue and grows until a small tumor forms. To grow, it needs new vessels.

Often cells die along the way, and only some survive; sometimes they remain inactive in a distant organ for years. A tumor can spread through lymphatic and blood vessels, through contact with the surface of an organ and through natural channels.

Are metastases cancer or not: the link to the primary tumor

A metastasis is not a new independent disease. Under a microscope its cells look like the cells of the primary tumor, not like the cells of the organ where the focus is found; by this sign doctors understand that the process came from another place.

A metastatic tumor has the same name as the primary one: breast cancer that has spread to the lung is called metastatic breast cancer, not lung cancer. If the source cannot be found, it is called cancer of unknown primary.

Most often metastases are found in the bones, liver and lungs, and in breast cancer also in the brain.

How metastases are diagnosed: imaging and tests

The diagnosis of metastases is based on examination of tissue: the nature of a focus is established by studying cells under a microscope. This may require a biopsy — the collection and examination of tissue, cells or fluid. The doctor asks about the medical history and orders blood tests and imaging, such as computed tomography. There is no single test that "shows metastases."

Whether a focus found on an image is a metastasis is determined by examining cells under a microscope (biopsy), not by a single picture.

Symptoms of metastases in different organs

A metastatic tumor does not always make itself known. When signs appear, they depend on the size and location of the secondary foci.

• in the bones — pain and fractures;
• in the brain — headache, seizures, dizziness;
• in the lungs — shortness of breath;
• in the liver — jaundice or abdominal enlargement.

Common signs that prompt a visit to a doctor: blood in urine or stool, bleeding and bruising without a cause, a wound that does not heal for a long time. Cancer often does not cause pain, so there is no need to wait for it: if a symptom does not go away within a few weeks, that is a reason to see a doctor.

Metastases and cancer stages

For many types of cancer, metastatic cancer is called stage 4 cancer. The details depend on the type of cancer and are determined by the doctor.

The size of the primary node alone does not indicate the tumor's ability to spread: it happens that a barely noticeable node produces extensive metastases, while a basal cell carcinoma growing with destruction of surrounding tissues produces no metastases at all.

Metastases alone are not a reason to call an ambulance; 103/112 — if seizures or severe shortness of breath occur.

This material is for reference and does not replace a doctor's consultation: only a specialist can discuss your specific situation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer