Abnormal cell growth that develops in the tissue of the longest portion of the large intestine defines colon cancer. The National Cancer Institute estimates that 102,900 new cases will be diagnosed in the United States in 2010. There are five stages of colon cancer, ranging from stage 0 to stage 4. In stage 0, the abnormal cells are confined to the innermost lining of the colon. By stage 1, the cells become cancerous and invade the middle lining. Stages 2 through 4 indicate advanced colon cancer.
Stage 2
In stage 2, cancer advances from the middle layers of tissue of the colon wall. This stage is subdivided into two phases. First, the cancer spreads from the muscular layer to the tissue surrounding the colon and rectum. Later, the cancer extends beyond the colon to adjacent organs and even through the peritoneum. The peritoneum is a thin membrane which lines the abdominal and pelvic cavities. The Merck Manuals rates the success rate of surgical intervention at 70 percent in cases of stage 2 colon cancer. An estimated 55 to 85 percent of individuals who are diagnosed and treated at this stage survive at least five years.
Stage 3
In stage 3, cancer extends beyond the muscular layer of the colon to at least three lymph nodes. According to the National Cancer Institute, this stage is subdivided into three phases. First, cancer spreads from the innermost tissue layers of the colon to the muscular middle layers and at least three lymph nodes. In the second phase, cancer cells spreads to at least 3 surrounding lymph nodes. Additional criteria includes either the cancer extends to nearby tissue around the colon or beyond the colon wall to adjacent organs The criteria for the third phase includes the same spread pattern but at least four nearby lymph nodes are affected .The Merck Manual explains that metastasis of colon cancer to the liver follows nearby lymph node involvement. Surgical removal of the cancerous bowel and adjacent lymph nodes has a 30 to 50 percent success rate in cases of stage 3 colon cancer. An estimated 20 to 55 percent of people who are diagnosed and treated at this stage survive at least five years.
Stage 4
In stage 4, cancer spreads to surrounding lymph nodes, liver, lungs, ovaries and the peritoneum. Less than one percent of people with stage 4 colon cancer survive at least five years. According to the American Cancer Society, surgery, such as a segmental resection, is performed to relieve or prevent blockage of the colon.
