Anatomy of the colon
The colon is a hollow,muscular tube that receives products of digestion from the small intestine and ultimately eliminates them from the body through the anus.The colon is located in the abdomen and has numerous sections that are named based on their location.
- The colon begins in the right lower abdomen with the cecum (located just above the appendix) into which the products of digestion empty from the small intestine.
- The ascending portion of the colon then ascends from the lower to the upper right side of the abdomen.
- It traverses the abdomen as the transverse portion of the colon from the right upper to left upper abdomen before descending from the upper to the lower left side of the abdomen.
- The last portions of the colon are the sigmoid colon low in the abdomen and finally the anus.
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What are the Symptoms of Colorectal Cancer?
Colon cancer can grow for years before causing symptoms. Often symptoms do not appear until the disease is already advanced. The development of these symptoms should prompt a visit to your primary care provider for evaluation.
- Bleeding from the rectum or blood in the stool.
- A change in bowl habits : diarrhea, constipation,or a feeling that the bowl does not empty completely.
- Stools that appear narrower or thinner than usual.
- Discomfort in the abdomen, including frequent gas pains, bloating, fullness, and cramps.
- Unexplained weight loss.
What is Colon Cancer Staging?
Staging is a method to describe how advanced a cancer is. Staging for colorectal cancer takes into account the depth of invasion into the colon wall, and spread to lymph nodes and other organs.
- Stage 0 (Carcinoma in Situ) Stage 0 cancer is also called carcinoma in situ. This is a pre cancerous condition,usually found in a polyp.
- Stage1: the cancer has spread through the innermost lining of the colon to the second and third layers of the colon wall.It has not spread outside the colon.
- Stage 2: The cancer has spread outside the colon to nearby tissues.
- Stage 3: Cancer has spread to nearby lymph nodes, but not to other parts of the body.
- Stage 4: Cancer has spread to other parts of the body, such as the liver or lungs.
Colon cancer is staged according to the pathological findings (results from biopsy) after surgery. Staging may include findings from imaging studies,such as chest x- ray,CT scan, a computer-assisted diagnostic procedure that produces cross sectional images of the body,MRI, Pet scan, and endorectal ultrasound. Not all of these tests are needed in every person. Staging helps the doctor to:
- Forecast how an individual may do over
- Estimate the risk of recurrence.
- Develop an individualized treatment plan for the patient.
Depending on the stage of the cancer, the doctor can recommend surgery alone or in combination with radiation and chemotherapy. The approach to treatment is individualized to each person and the stage of the disease.
The body is made up of different types of cells that normally divide and multiply in an orderly way. These new cells replace older cells.This process of cell birth and renewal occurs constantly in the body. Cancer or malignant growths occur when:
- Some cells in the body begin to multiply in an uncontrolled manner.
- The body's natural defenses, such as certain parts of the immune system,cannot stop uncontrolled cell division.
- These abnormal cells become greater and greater in number.
- In some types of cancer,including colon cancer,the uncontrolled cell growth forms a mass,also called a tumor. Some tumors are benign,which means that they are not cancerous. Cancerous or malignant tumors grow out of control and can invade, replace, and destroy normal cells near the tumor. In some cases, cancer cells spread to other areas of the body. There are two kinds of growths that occur in the colon:
- Non cancerous growths, such as polyps.
- Malignant or cancerous growths.
Colon Cancer usually begins with the growth of benign growths such as polyps. If a polyp develops and is not removed, it may become cancerous. Once a cancer develops it begins to invade the intestinal wall and may spread to nearby lymph nodes. Lymph nodes are part of the lymphatic system,which carries special filtered fluids throughout the body. Through the lymphatic system, cancer cells may also be carried to areas of the body far away from the original tumor. The spread of cancer may also occur via the blood stream. Colon and rectal cancers that
metastasize through the blood stream will travel first to the liver. There the cancerous cells may continue to grow and develop new tumors. As these new tumors continue to grow and spread further the function of vital organs, such as the liver, may deteriorate.