Cancer is identified by the place in the body where it originated. This means that cancer that started in the colon is identified as colon cancer, even if it has metastasized — spread — to other parts of the body. While it is not uncommon for primary cancer to occur in the liver, colon cancer also quite often will metastasize to the liver, causing cancer to grow there as well. Colon and liver cancer frequently occur together, with the colon cancer being the primary cancer and the liver cancer being the secondary cancer.
When this happens, the cancer in the liver is still considered to be colon cancer, because that’s where it began. This holds true even if the liver is fully involved and requires treatment in addition to any treatment done for the colon cancer. The drugs chosen for colon and liver cancer chemotherapy are based on the fact that the problem is colon cancer on the liver, and as such they may be different from drugs that are used for primary liver cancer.
Primary liver cancer is not related to colon cancer. Although the cause of liver cancer is not always known, it appears to be related to such factors as a fatty liver, diabetes, liver disease, and cirrhosis, among other things. Hepatitis is known to cause liver cancer, over time. Although it is possible for this cancer to spread anywhere in the body, it does not usually metastasize to the colon.
Primary colon cancer can also be caused by many things, although the exact cause is usually not certain. Colon polyps may become cancerous, which is why they are normally removed during a colonoscopy. Risk factors are long-term colon irritation, a family history of colon cancer, diabetes, a sedentary lifestyle, and a low fiber, high fat diet. Whatever the cause, people who develop colon cancer are at risk for developing secondary liver cancer and ending up dealing with both colon and liver cancer.
A person with both colon and liver cancer will receive treatment that targets both areas. Surgery is often required to remove as much of the cancer as possible, and the colon and liver may be operated on at the same time. Chemotherapy will normally target colon cancer, but it is possible that additional drugs will be used that target liver cancer as well. If radiation is required, it will also be used for both cancers, to remove what is there and to prevent further spread of both the colon and liver cancer.