How Cancer Spreads

Cancer is a dangerous disease regardless ofcells must attach themselves into a new tissue to
where it is located in the body. It is even moreform a secondary tumor.
dangerous than normal when it is located in anThe official term for the spread of cancer is
area that has a high number of blood vessels ormetastasis. When the cells spread to a different
other conveyors of bodily fluids. Tumors in thesepart of the body, the new tumor is a metastatic
areas are more dangerous because there is atumor. The cells are from the original tumor so
higher chance that the cells from the originalthe new tumor is made up of the same type of
tumor will break off and re-establish themselvescells as the original tumor. For example, if cells
elsewhere.from a breast cancer tumor spread to the lungs,
Contrary to what many think, the majority ofthe new tumor is made up of cancerous breast
deaths from cancer are not actually caused bycells, not lung cells. The cells will look the same as
the original tumor. Death from cancer is mostcells from the original tumor under a microscope.
frequently caused by secondary tumors that areIt is possible for cells from one cancer site to
formed when the original tumor goes from beingspread to almost any part of the body. If the
benign (not harmful) to malignant (harmful).cells go from the original site to a lymph node
Secondary tumors are formed when cells fromnear the primary or original tumor, the cancer is
the original, primary tumor split away, are carriedcalled "lymph node involvement" or "regional
to other parts of the body (metastasis), and thendisease." If the cells spread far away to the
re-establish themselves in the tissues and start toopposite end of the body, this is "metastatic
grow. Metastasis is a very complex process thatdisease" or "distant disease."
requires a variety of events to be successful. TheWhen cancer spreads from a solid tumor, it most
first thing that must happen is that the cells mustcommonly goes to the lungs, bones, liver, and
detach themselves from the primary tumor.brain. While these are the most common locations
Next, the cell must be picked up by thefor spreading, no area of the body is really safe.
bloodstream or the lymphatic system. Finally, the