What is cancer rate of spreading?

Very variable: Some cancers are so slow growing that a person is likely to die with the cancer than from it; some prostate cancers fall in that category. Others are fulminant and can kill between the diagnosis is made and treatment could be started, e.g., pro-myelocytic leukemia.

Why do you ask?: There are hundreds of different relatively common kinds of cancer, and even for individual kinds, the speed at which it spreads is unpredictable. The leukemias are by definition spread through the body by the time of discovery. Basal cell carcinomas, almost never. Glioblastomas are always spread in the brain but don't go beyond. Otherwise, it's almost always percentage odds.