Hi Aspirant,

Definition- The spread of cancer cells from the place where they first formed to another part of the body.

Metastasis is a complex process that involves the spread of a tumor or cancer to distant parts of the body

In metastasis ,cancer cells break away from the original(primary) tumor,travel through the blood or lymph system,and form a new tumor in other organs or tissues of the body.The new , metastatic tumor is the same type of cancer as the primary tumor.

For Ex- if breast cancer spreads to the lung,the cancer cells in the lung are breast cancer cells,not lung cancer cells.

many cancer deaths are caused when cancer moves from the original tumor and spreads to other tissues and organs.This is called metastatic cancer.

Steps of metastasis

1)separation from the primary tumor

2)invasion through tissues around the initial lesion and penetration of their         basement membranes

3)entry into blood vessels and survival within blood spread via blood vessels is called hematogenous  spread

4)entry into lymphatics or peritoneal cavity

5)reaching the distant organ

6)formation of a new lesion along with new blood vessels feeding the tumor formation of new blood vessels is termed angiogenesis.

There are 4 routes of spread of cancer

1)spread via lymphatic channels

2)spread via blood vessels

3)spread via body cavities

4)transplantation of cancer.

Hope this helps you!

GOOD LUCK!!