- Last update on 15 April 2012
- under Colon Cancer
Cancer is a class of diseases characterized by out-of-control cell growth and colon cancer forms when this uncontrolled cell growth initiates with cells in the large intestine. most colon cancers originate from small, noncancerous (benign) tumors called adenomatous polyps that form on the inner walls of the large intestine. some of these polyps may grow into malignant colon cancers over time if they are not removed during colonoscopy. Colon cancer cells will invade and damage healthy tissue that is near the tumor causing many complications.
After malignant tumors form, the cancerous cells may travel through the blood and lymph systems, spreading to other parts of the body. these cancer cells can grow in several places, invading and destroying other healthy tissues throughout the body. this process itself is called metastasis, and the result is a more serious condition that is very difficult to treat.
Colon cancer is not necessarily the same as rectal cancer, but they often occur together in what is called colorectal cancer. Rectal cancer originates in the rectum, which is the last several inches of the large intestine, closest to the anus.
In the United States, about 112,000 people are diagnosed with colon cancer each year.
Cancer symptoms are quite varied and depend on where the cancer is located, where it has spread, and how big the tumor is. It is common for people with colon cancer to experience no symptoms in the earliest stages of the disease. However, when the cancer grows, symptoms include:
If the cancer spreads, or metastasizes, additional symptoms can present themselves in the newly affected area. Symptoms of metastasis ultimately depend on the location to which the cancer has spread, and the liver is the most common place of metastasis.
Management of colon cancer relies primarily on surgical removal of the tumor and some of the surrounding tissues. the need for further treatment with chemotherapy or radiation therapy is determined upon evaluation of the resected cancer. Surgery is the oldest method of treating this cancer with the idea being complete removal of the cancer from the body. Cure is possible in cases where the cancer is limited to the bowel, with no spread to the other tissues. Surgery is done in the hospital and under general anesthesia. Patients may stay in the hospital for 7-10 days after surgery. Chemotherapy may be needed, as indicated by the stage of the illness, and patient’s overall condition.
In the laboratory, the pathologist will examine the margins the removed piece of bowel. he will also determine the depth of penetration of the cancer as well as any lymph node involvement. this is referred to as Pathological Staging. the need for further treatment is dependent on the full staging of the cancer.
Several types of cancer can start in the colon or rectum.
Adenocarcinomas: More than 95% of colorectal cancers are a type of cancer known as adenocarcinomas. these cancers start in cells that form glands that make mucus to lubricate the inside of the colon and rectum. When doctors talk about colorectal cancer, this is almost always what they are referring to.
Other, less common types of tumors may also start in the colon and rectum. these include:
Carcinoid tumors: these tumors start from specialized hormone-producing cells in the intestine. They are discussed in our document, Gastrointestinal Carcinoid Tumors.
Gastrointestinal stromal tumors (GISTs): these tumors start from specialized cells in the wall of the colon called the interstitial cells of Cajal. some are benign (non-cancerous); others are malignant (cancerous). these tumors can be found anywhere in the digestive tract, but they are unusual in the colon. They are discussed in our document, Gastrointestinal Stromal Tumors (GIST).
Lymphomas: these are cancers of immune system cells that typically start in lymph nodes, but they may also start in the colon, rectum, or other organs. Information on lymphomas of the digestive system is included in our document, Non-Hodgkin Lymphoma.
Sarcomas: these tumors can start in blood vessels as well as in muscle and connective tissue in the wall of the colon and rectum. Sarcomas of the colon or rectum are rare. They are discussed in our document, Sarcoma – Adult Soft Tissue Cancer.
Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and when this process breaks down, cancer results. Colon cancer cells do not experience programmatic death, but instead continue to grow and divide. Although scientists do not know exactly what causes these cells to behave this way, they have identified several potential risk factors.
Related Articles: About BaskanTags: United States, rectal cancer, several inches, adenomatous polyps, Non-Hodgkin Lymphoma.Sarcomas, colorectal cancers, colon cancers