What is Colorectal Cancer?

A type of cancer called adenocarcinoma accounts for more than 95 percent of cancers in the colon and rectum – this is usually what is meant by the term "colorectal cancer" – but other, more rare types of cancer also can be found in the colon and rectum.

Colorectal Colon Cancer

Types of Colorectal Cancers

The vast majority of colorectal cancers are adenocarcinomas, which are tumors that start in the lining of internal organs in cells with glandular (secretion) properties. In colorectal cancer, early tumors start as small adenomatous polyps that continue to into malignant tumors.

Carcinoids are tumors that start in special hormone-producing cells in the intestine. Often, they cause no symptoms at first, but eventually they may cause facial flushing and diarrhea. Surgery is the usual treatment but injections can also be used to treat symptoms.