Why is secondary liver cancer from the colon cancer so hard to treat?

Depends: It very much depends on the cell type of the cancer, the size of the liver tumors, the number of liver tumors, and where the tumors are located in the liver. Sometimes surgery can be used if the tumors are not too big or too numerous, and not located in a vital area of the liver. Tumors that spread may have more aggressive cells and not respond to chemotherapy as well too.

Colon ca mets: To live is hard to treat because many times the metastasis is on multiple lobe of the liver and cannot be surgically removed. Surgeon only do surgery with the intention of cure if they can remove the metastasis completely. If surgery is not possible you should still consider chemotherapy. The quality of life is still pretty good even if not cured.