Cancerous cells are of two types called benign and malignant. The benign cells are considered as non-cancerous cells and they do not spread to other parts of the body. These would look like cysts and can be removed through surgery. The malignant tumors are those that spread to the adjacent organs of the body. If left untreated they would spread to the other tissues and damage them too. In some cases the cancerous cells would enter the blood stream. Once it goes into the blood stream, it will spread easily even to the organs that are remote.
The metastasis is used to indicate the spreading of the cancerous cells. Even thought cancer spreads to the other organs the originating organ is referred to the cancer mostly. For example a cervical cancer is called so even if it spreads to the lungs. Different types of treatment are available for treating different cancers.