Scientists Begin to Grasp the Stealthy Spread of Cancer - New York Times: "The moment when a cancer begins to spread throughout the body — metastasis — has always been the most dreaded turning point of the disease.


Without metastasis, cancer would barely be a blip on the collective consciousness. Fewer than 10 percent of cancer deaths are caused by the primary tumor; the rest stem from metastasis to vital sites like the lungs, the liver, the bones and the brain."