Metastasis facts for kids

Metastasis is when cancer cells spread from where they first started to other parts of the body. Imagine a tiny seed from a plant floating away and growing into a new plant somewhere else. Cancer cells can do something similar. They travel through your bloodstream or lymphatic system to new places. When they reach a new spot, they can start to grow and form a new tumor. This spreading makes cancer much harder to treat.

What is Metastasis?

Metastasis is the process where cancer moves from its first home to new areas. The original cancer is called the primary tumor. When cancer cells break away from this primary tumor, they can travel through your body. If they settle and grow in a new place, they form a secondary tumor. These new tumors are still the same type of cancer as the original one. For example, if breast cancer spreads to the lungs, it's still breast cancer, not lung cancer.

How Cancer Cells Spread

Cancer cells are very clever at finding ways to travel. Here's how they usually spread:

• Direct Spread: The cancer grows directly into nearby tissues. Imagine a plant's roots growing into the soil around it.
• Through the Bloodstream: Cancer cells can get into your blood vessels. Once in the blood, they can travel to almost any part of your body. This is like taking a highway to a new city.
• Through the Lymphatic System: Your body has a network of vessels called the lymphatic system. This system helps fight infections and carries a fluid called lymph. Cancer cells can enter these vessels and travel to lymph nodes or other organs. Think of this as another road system in your body.

When cancer cells reach a new place, they need to attach themselves and start growing. They might form a new tumor right away, or they might stay quiet for a while before growing.

Why Metastasis Makes Treatment Harder

When cancer spreads, it becomes more serious. Here's why:

• More Places to Treat: Instead of just one tumor, doctors now have to deal with tumors in multiple places.
• Harder to Remove: It's often impossible to remove all the tumors with surgery once cancer has spread widely.
• Different Treatments Needed: The type of treatment might change depending on where the cancer has spread.
• Impact on Body: Tumors in new places can affect how those organs work, causing more health problems.

Doctors work hard to find out if cancer has spread. They use special tests like CT scans, MRIs, and PET scans. Knowing if cancer has spread helps them plan the best way to fight it.

Images for kids

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  A lymph node almost completely taken over by metastatic melanoma. The brown color is from melanin.

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  Pulmonary metastases seen on a Chest X-Ray.

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  Micrograph of thyroid cancer (papillary thyroid carcinoma) in a lymph node of the neck.

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  CT image showing multiple liver metastases.

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  CT image of a lung metastasis.

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  Metastasis confirmed by liver biopsy (tumor—lower two-thirds of image).

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  Metastases from the lungs to the brain.

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  Metastases from the lungs to the pancreas.

See also

In Spanish: Metástasis para niños