Liver metastases

Liver metastases are cancer that started somewhere else in the body and later spread to the liver. Metastasis is the process by which cancer cells spread to other parts of the body. Here's the interesting part: those cells don't turn into liver cells. They still look like the cells of the original cancer. Think of someone who moves to a new city and keeps the accent from back home. That's why the disease keeps the name of where it started: breast cancer that has reached the liver is still breast cancer.

So why the liver? The answer lies in how blood gets there. The liver has a dual blood supply, meaning it receives blood through the hepatic artery (hepatic means "having to do with the liver") and also through the portal vein. The portal vein collects the blood leaving the pancreas, the spleen, and almost all of the digestive tract, the long tube that food travels through. Picture a station where the roads from nearly the entire digestive system all come together: whatever travels in that blood passes through the liver. That's why, when cancer starts in the digestive system, the liver is an especially likely place for it to spread.

Of all the cancers that reach the liver, the most common is colorectal cancer, meaning cancer of the colon and rectum. Next come pancreatic cancer and breast cancer.