In a discovery that opens up the possibility of stopping the spread of cancer before it has a chance to take hold elsewhere in the body, researchers have developed a means of tracking cancer cells as they spread past the original tumor.

Robarts Research Centre in London, Ontario researchers have announced a new technology that allowed them, for the first time, to follow single breast cancer cells as they migrated from the body to the brain. According to statistics, 22 to 30 per cent of women with breast cancer will suffer from cancer that spreads to the brain.

Interestingly, the new technology also allows them to watch which cancer cells that have spread into the brain develop into a tumor, and which ones remain dormant, or die off. Not all cancer cells become a cancerous tumor.

Of the new technology, Dr. Paula Foster says, "It will give us the ability to test what genes are important, what drugs actually work, how the drugs work. Then you can take that information to patients and hopefully treat this disease a little better."

This is the biggest fear of cancer survivors -- that the cancer will come back, that it will have spread.