How does cancer spread?

In many ways: Cancers can spread in many ways- it spreads to distant organs through the blood vessels or through lymph nodes or along nerves. It can also spread locally by directly growing into surrounding organs.

Cancer Spread: Cancer can spread directly by growing into adjacent tissues, or by penetrating blood and lymph vessels and traveling to regional lymph nodes and via the bloodstream to distant organs. Even if it does, in many cases, in addition to surgical treatment, there are chemo therapeutic, radiation, biological (immune) therapies, and targeted drug therapies available for many cancers.

See below: Cancer can spread by invading nearby tissues, by invading lymphatics and thus gaining entry into blood and by invading veins and spreading through the blood stream. See this site for more info. http://www.cancer.gov/cancertopics/factsheet/sites-types/metastatic.