The liver is the single major organ that can regenerate itself. While metastasis in the liver (secondary cancer) is very bad, primary cancer of the liver is fairly rare. Unless a focused, local radiation dose is received by the liver, if you get enough exposure to damage the liver you have received far worse damage to your intestinal tract, your bone marrow, and/or brain.
WRT radiation, the liver is only minimally affected in comparison to other body tissues/organs.
Steve (soon to be a Certified Nuclear Medicine Tech, one more semester of study and then 7 months "internship") Johnson