How quickly does testicular cancer spread?

Quickly at times: Testicular cancer has a very fast onset. Testicular cancer grows rapidly, with tumors doubling in size in just 10 to 30 days. Testicular cancer can metastasize quickly, meaning that it can spread to other parts of the body. There is a high cure rate if found early (approaching 100%).

Depends on cell type: Most testicular cancers grow fairly fast, and many of them have already spread even when diagosed early and primary tumor is small. Mature teratomas of testis tend to grow slowly and seldom spread. Other end of spectrum is the so called choriocarcinoma which is extremely malignant, & grows & spreads very fast. Both are uncommon. However never delay when a testicular lump is found.