How do most cancer cells spread from their original site?

Cancer cells have developed a mechanism of replicating faster than other normal cells-making cancer cells stronger and faster than other cells in your body.

While they grow quickly, they can't grow by themselves. Just as a plant needs water or a child needs vitamins, cancer cells also need nutrients to grow. The one thing that cancer cells want more than anything else is energy. If the cells don't get it, then they'd actually kill themselves off because they'd outgrow their energy supply.

The most successful cancers (well, successful from the point of view of cancer, meaning the cancers that grow large enough to be detected by your immune system and to be harmful) often find ways to grow supply lines in the form of attracting blood vessels to them.

Once they can establish those supply lines, it's like attaching an oxygen tank to someone under water-it gives them a pathway to breathe and sustain themselves. And in cancer, that's what gives them a lifeline to live and grow-and helps them eventually spread to other areas of your body.

Since they're belligerent cells, cancer cells decide which blood vessels they want to take to other organs. They can surround regular tissue and dominate the organ they've invaded, and as they cluster together, they can form tumors-a clumped mass of cancer cells-to block the normal functioning of that organ.

Cancer cells also don't have the stickiness that other cells have, so they can slip away through their newly created blood vessels and spread to other parts of the body-very often to the liver, lungs, and brain where metasteses frequently occur.

Typically, cancer likes to escape to and grow in areas with lots of blood, which is why it's common for cancer from one area to jump and grow in another organ. And cancer loves traveling through the lymphatic system (the body's waste disposal program) to the closest lymph nodes, which is why doctors always examine these areas carefully.