The real killer in cancer is its spread within the body: metastasis. A reliable method of eliminating metastasis would go a long way to making cancer just a bad, treatable condition rather than the end of life for a quarter of us. Here is one approach: researchers have "found a way to capture tumor cells in the bloodstream that could dramatically improve earlier cancer diagnosis and prevent deadly metastasis. ... researchers can inject a cocktail of magnetic and gold nanoparticles with a special biological coating into the bloodstream to target circulating tumor cells. A magnet attached to the skin above peripheral blood vessels can then capture the cells. ... By magnetically collecting most of the tumor cells from blood circulating in vessels throughout the whole body, this new method can potentially increase specificity and sensitivity up to 1,000 times compared to existing technology ... Once the tumor cells are targeted and captured by the magnet, they can either be microsurgically removed from vessels for further genetic analysis or can be noninvasively eradicated directly in blood vessels by laser irradiation through the skin that is still safe for normal blood cells."