Cancer cells have the tendency to spread to other part of the body from the site of their origin. This mechanism of the cancerous cell is known as metastasis. Cancer spreads to other parts of body through various means which involves many steps.
So, what are those steps?
Local invasion:
This is the simplest step of spreading. Cancerous cell just invade the nearby organ through the normal tissues.
Intravasation:
Cancerous cells move through the walls of lymph and blood vessels.
Circulation:
This is when these cells flow through the lymphatic system or the bloodstream to other parts or organ of the body.
Arrest and extravasations:
In this type of spread, the cancerous cells arrest themselves inside a blood capillary after moving from the site of origin. They then try to spread to other blood capillary or lymph nodes of the neighboring organs by invading the cell walls.
Proliferation:
The cancer cells multiply at a location far from the cancer site and then turn into a mass of tumorous cell which is called micro metastases.
Cancer spreads
to other part of the body by its ability to metastasize and this ability depends on their properties, such as:
Types of cells they are encountering while spreading or inside the bloodstream and lymphatic system.
The kind of immune cells they cross.
The final destination i.e. the organ or the part of body they are invading.
Not all cancerous cells have the ability to metastasize. It might happen that the noncancerous cells (immune cells) at the location might block the cancerous cell to metastasis. One more important thing to note here is, it’s not necessary that if the cancer cells have invaded a new organ it will form a tumor. They may lie in dormant state for many years and then starts to multiply again.