Colon polyps usually cause no symptoms. Without screening and early detection by colonoscopy, polyps may be silently present for many years, growing larger day by day. Eventually, certain types of colon polyps will become malignant. This is called adenocarcinoma of the colon, or colon cancer. As time goes by, the cancer may spread. The symptoms of colon cancer often don’t arise until it’s too late. There are five stages of colon cancer, each more serious than the one before.
- Stage 0 -When removed and biopsied, some adenomas or villous adenomas are found to harbor a small focus of actual cancer cells. The cancer is found only on the very surface of the polyp and has not yet invaded into the central core. This earliest stage is also called carcinoma in situ.
- Stage 1 -The cancer is localized to the surface of the colon. Stage 1 used to be called Duke’s A colon cancer.
- Stage 2 -The cancer is eating into the wall of the colon. Stage 2 used to be called Duke’s B colon cancer.
- Stage 3 -The cancer has eaten through the wall of the colon and spread to the lymph glands on the outside of the colon. Stage 3 used to be called Duke’s C colon cancer.
- Stage 4 -The cancer has overflowed the lymph glands and spread beyond, usually into the liver. Stage 4 used to be called Duke’s D colon cancer.