The spread of cancer, metastasis, is the cause of 9 out of 10 cancer deaths. Unfortunately, there are currently no drugs that are effective in preventing metastasis. For many years, it was believed that cancer spread from the initial tumor only when the cancer cells had developed many new mutations that allowed them to leave and survive. We are learning that it is more complicated than that.
Many cancers seem to spread around the body early in the development of the disease. The cells that leave don't always grow in this new location right away. Sometimes the cells lay quiet (dormant) for years before becoming activated and forming new tumors. Researchers working on this believe that preventing this awakening could be an important new target for treatments. It is important to know why the cells are inactive and what causes them to wake up. Several drugs and drug combinations are currently being studied to see if they can prevent the cancer cells from 'waking up' and growing. The cancer would not be gone, but it would be held at bay - keeping the sleeper cells asleep.