Understanding / Info
Metastasis
The spread of cancer cells from the site of origin to other organs or tissues. Metastases form when cancer cells enter the blood or lymph and settle elsewhere.
What it means
The spread of cancer cells from the site of origin to other organs or tissues. Metastases show that the disease has spread to distant sites and they influence the stage, the prognosis and the type of treatment recommended.
In short
The spread of cancer cells from the site of origin to other organs or tissues. Metastases form when cancer cells enter the blood or lymph and settle elsewhere.
Where you will see it
Mentioned on imaging (CT, MRI, PET-CT, bone scan) and in TNM staging as M1.
What it does not tell you on its own
The presence of metastases does not tell you how many organs are involved, whether the disease is responding to treatment or how fast it is progressing. The response is assessed periodically through imaging.
Questions for your doctor
- Are there metastases in my case?
- Which organs are involved?
- What is the treatment plan?
- Are there local treatment options in addition to the systemic treatment?
Related terms
The terms below often appear alongside this one. Each definition is right here, so you do not have to look elsewhere.
- TNM (staging system)
- The international system for classifying cancer according to three dimensions: T = the size of the primary tumor, N = the involvement of the lymph nodes, M = the presence of metastases. It is the basis for stages I–IV and determines the treatment plan.
- PET-CT (positron emission tomography)
- A combined investigation that joins metabolic information (PET) with anatomical detail (CT). It shows which cells are very active (consuming a lot of glucose) and helps detect the spread of the disease, identify small nodules and assess the response to treatment.
- Lymph node
- A small structure of the lymphatic system, involved in the body's defence. In cancer, the lymph nodes are important for staging, because they can be the route by which the disease begins to spread.
- Prognosis
- An estimate of the likely course of the disease. It depends on the type of cancer, the stage and the response to treatment.
- Stage (I–IV)
- An international classification (the TNM system) that shows how far the cancer has spread: T = the primary tumor, N = lymph nodes involved, M = metastases. Stage I = localised disease, Stage IV = disease that has spread to distant sites. The stage determines the treatment plan.
Other terms in “Basics”
Glossary definitions are written for patients by the OncoDots team and go through internal medical review. They explain terms; they do not establish a diagnosis and do not recommend a treatment.