Colon
Rectal
Small Intestine
Anal
Colon
Colon cancer is also known as colorectal cancer, a term that refers to both colon and rectal cancers. The two are often grouped together because they start in the large intestine. The colon is the final part of the digestive tract, the first five feet of the large intestine, and absorbs water from stool. Colon cancer typically starts as small, noncancerous (benign) polyps on the inner lining of the colon. It’s usually treated with surgery, which is made easier because the colon is located in the belly.
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Colorectal Cancer: Highly Preventable, Highly Treatable
Rectal
Along with colon cancer, rectal cancer is also known as colorectal cancer, because both start in the large intestine. Rectal cancer involves the last six inches of the large intestine. This is the rectum, where your body stores stool until a bowel movement. Rectal cancer usually starts with polyps on the inner lining of the rectum. Tumors in the lower rectum may also be close to the anal sphincter muscle, which is important for using the bathroom normally. This can affect treatment options. Surgery is a common treatment for rectal cancer, though its location surrounded by the pelvis and other organs can make surgery more challenging.
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Colorectal Cancer: Highly Preventable, Highly Treatable
Small Intestine
Small intestinal cancer occurs in the gastrointestinal (GI) tract or digestive tract. This cancer is less common than most other types of GI cancers. The small intestine is made up of many different types of cells, so different types of cancer can start here.
The four major types of small intestinal cancers are:
- Adenocarcinomas. This type starts in the gland cells that line the inside of the intestine.
- Carcinoid tumors. A type of neuroendocrine tumor that tends to be slow growing and is the most common type of small intestinal tumor.
- Lymphomas. This type starts in immune cells called lymphocytes.
- Sarcomas. This type starts in connective tissues, such as muscle. The most common sarcomas in the intestine are known as gastrointestinal stromal tumors (GISTs).
The symptoms can have other, more common causes, such as belly pain, nausea and vomiting, unexplained weight loss, fatigue, dark-colored stools, anemia and jaundice.
Anal
Anal cancer is a rare disease that starts in the one- to two-inch-long anal canal, which connects the anus to the rectum. It’s the end of the digestive system and the part of the body that excretes solid waste. Anal cancer is also called carcinoma of the anal canal. The anus is made up of tissue from the skin and the intestine. Anal cancers are often divided into two groups based on where they start: cancers of the anal canal (above the anal verge) and cancers of the perianal skin (below the anal verge). It can also start in three different types of cells:
- The most common type is squamous cell carcinoma, a type of skin cancer.
- Adenocarcinoma of the anus is less common and starts in glandular cells that make the mucus that helps stools pass through the anus smoothly.
- Melanoma, another rare type of anal cancer, starts in skin cells called melanocytes.
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Learn About the Signs and Symptoms of Anal Cancer