Colorectal Cancer Savannah, Ga
The colon is the the large intestine. It has four sections.
The first section is called the ascending colon. It extends upward on the right side of the abdomen.
The second section is called the transverse colon since it goes across the body to the left side.
There it joins the third section, the descending colon, which continues downward on the left side.
The fourth section is known as the sigmoid colon because of its S-shape.
The sigmoid colon joins the rectum, which, in turn, joins the anus, or the opening where waste matter passes out of the body.
Colorectal cancer is malignant cells found in the colon or rectum. The colon and the rectum are parts of the large intestine, which is part of the digestive system. Because colon cancer and rectal cancers have many features in common, they are sometimes referred to together as colorectal cancer. Cancerous tumors found in the colon or rectum also may spread to other parts of the body.
Excluding skin cancers, colorectal cancer is the fourth most common cancer in both men and women in the U.S. The American Cancer Society estimates that about 140,000 colorectal cancer cases and 50,000 deaths occur each year. The number of deaths due to colorectal cancer has decreased, which is attributed to increased screening and polyp removal and to improvements in cancer treatment.
A type of cancer called adenocarcinoma accounts for more than 95 percent of colorectal cancers. It is the type we focus on in this section. These are other types of cancer that can be found in the colon and rectum, but they are rare.
Here is an overview of the types of colorectal cancer:
Adenocarcinomas are tumors that start in the lining of internal organs. "Adeno" means gland. These tumors start in cells with glandular properties, or cells that secrete. They can form in many different organs, such as the lung or the breast. In colorectal cancer, early tumors start as small adenomatous polyps that continue to grow and can then turn into malignant tumors.
- gastrointestinal stromal tumors (GIST)
These are tumors that start in specialized cells in the wall of the digestive tract called the interstitial cells of Cajal. These tumors may be found anywhere in the digestive tract, although they rarely appear in the colon. They can be benign (noncancerous) at first, but many do turn into cancer. When this happens, they are called sarcomas. Surgery is the usual treatment if the tumor has not spread.
A lymphoma is a cancer that typically starts in a lymph node, which is part of the immune system. However, it can also start in the colon, rectum, or other organs.
Carcinoids are tumors caused by hormones. They start in special hormone-producing cells in the intestine. Often they cause no symptoms at first. Surgery is the usual treatment.
Tumors that start in blood vessels as well as in muscle and connective tissue in the the wall of the colon and rectum.
The following are the most common symptoms of colorectal cancer. However, each individual may experience symptoms differently.
People who have any of the following symptoms should check with their physicians, especially if they are over 50 years old or have a personal or family history of the disease:
- a change in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
- rectal bleeding, dark stools, or blood in the stool
- cramping or gnawing stomach pain
- decreased appetite
- unintended weight loss
- weakness and fatigue
- a feeling that you need to have a bowel movement that is not relieved by doing so
The symptoms of colorectal cancer may resemble other conditions, such as infections, hemorrhoids, and inflammatory bowel disease. It is also possible to have colon cancer and not have any symptoms. Always consult your physician for a diagnosis.
Risk factors may include:
A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases, including cancers, have different risk factors.
Although these factors can increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors. But, knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
Most people who have colorectal cancer are over age 50; however, it can occur at any age.
- race and ethnicity
African-Americans have the highest risk for colorectal cancer ofall racial groups in the U.S. Jews of Eastern European descent (Ashkenazi Jews) have the highest colorectal cancer risk of any ethnic group in the world.
Colorectal cancer is often associated with a diet high in fat and calories, and low in fiber.
- personal history of colorectal polyps
Benign growths on the wall of the colon or rectum are common in people over age 50, and may lead to colorectal cancer.
- family history
People with a strong family history of colorectal cancer or polyps in a first-degree relative (in a parent or sibling before the age of 45 or in two first-degree relatives of any age), have an increased risk for colorectal cancer.
- ulcerative colitis
People who have ulcerative colitis, an inflamed lining of the colon, have an increased risk for colorectal cancer.
- inherited syndromes
such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colon cancer (HNPCC), also known as Lynch syndrome
- physical inactivity
- heavy alcohol consumption
- type 2diabetes
The exact cause of most colorectal cancer is unknown, but the known risk factors listed above are the most likely causes. A small percentage of colorectal cancers are caused by inherited gene mutations. People with a family history of colorectal cancer may wish to consider genetic testing. The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of these test results.
Persons with a family history of colorectal cancer may wish to consider genetic testing. The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of the results.
Although the exact cause of colorectal cancer is not known, it may be possible to lower your risk of colorectal cancers with the following:
Screening methods for colorectal cancer, for people who do not have any symptoms or strong risk factors, include the following:
- digital rectal examination (DRE) - a physician or healthcare provider inserts a gloved finger into the rectum to feel for anything unusual or abnormal.
- fecal occult blood test (FOBT) - checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in a laboratory.
- fecal immunochemical test (FIT) - a test that is similar to a fecal occult blood test, but does not require any restrictions on diet or medications prior to the test.
- One of the following:
- sigmoidoscopy - a diagnostic procedure that allows the physician to examine the inside of a portion of the large intestine. A short, flexible, lighted tube with a small video camera on the end, called a sigmoidoscope, is inserted into the intestine through the rectum. The scope blows air into the intestine to inflate it and make viewing the inside easier.
- colonoscopy - a procedure that allows the physician to view the entire length of the large intestine, and can often help identify abnormal growths, inflamed tissue, ulcers, and bleeding. It involves inserting a colonoscope, a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the physician to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.
- CT colonography (virtual colonoscopy) - a procedure that uses computerized tomography (CT) scans to examine the colon for polyps or masses. The images are processed by a computer to make a 3-dimensional (3-D) model of the colon. Virtual colonoscopy is non-invasive and does not require an insertion of a tube into the rectum, as in colonoscopy. However, if something abnormal is seen with this test, a standard colonoscopy may be required.
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- barium enema with air contrast (also called a double contrast barium enema.) - a fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an X-ray) is administered into the rectum to partially fill up the colon. Air is then pumped in to expand the colon and rectum. An X-ray of the abdomen is then taken and can show strictures (narrowed areas), obstructions (blockages), and other problems.
|Screening Guidelines for Colorectal Cancer|
|Colorectal cancer screening guidelines for 2008 from the American Cancer Society for early detection include:
- Beginning at age 50, both men and women should follow one of the examination schedules below:
- fecal occult blood test (FOBT) or fecal immunochemical test (FIT) every year
- flexible sigmoidoscopy (FSIG) every five years
- both annual FOBT and FSIG every five years
- double-contrast barium enema every five years
- colonoscopy every 10 years
- CT colonography (virtual colonoscopy) every five years
- People with any of the following colorectal cancer risk factors should begin screening procedures at an earlier age and be screened more often:
- strong family history of colorectal cancer or polyps in a first-degree relative, in a parent or sibling before the age of 45 or in two first-degree relatives of any age
- family with hereditary colorectal cancer syndromes, such as familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC)
- personal history of colorectal cancer or adenomatous polyps
- personal history of chronic inflammatory bowel disease
In addition to a complete medical history and physical examination, diagnostic procedures for colorectal cancer may include the following:
- digital rectal examination (DRE) - a physician or healthcare provider inserts a gloved and lubricated finger into the rectum to feel for anything unusual or abnormal. This test can detect some cancers of the rectum, but not the colon.
- fecal occult blood test - checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then sent to a laboratory.
- sigmoidoscopy - a diagnostic procedure that allows the physician to examine the inside of a portion of the large intestine. A short, flexible, lighted tube with a small video camera on the end -- called a sigmoidoscope -- is inserted into the intestine through the rectum. The scope blows air into the intestine to inflate it and make viewing the inside easier.
- colonoscopy - a procedure that allows the physician to view the entire length of the large intestine. It involves inserting a colonoscope, a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the physician to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.
- barium enema (also called double contract barium enema) - a fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is administered into the rectum to partially fill up the colon. An X-ray of the abdomen is then taken that can show strictures (narrowed areas), obstructions (blockages), and other problems.
- biopsy - a procedure in which polyps or tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope to determine if cancer or other abnormal cells are present.
- blood count - a test to check for anemia that can be a result of bleeding from a tumor.
Imaging tests - such as a CT scan, PET scan, ultrasound, or MRI of the abdomen, may be done to look for tumors or other problems. These tests may also be done if colorectal cancer has already been diagnosed to help determine the extent (stage) of the cancer.
When colorectal cancer is diagnosed, tests will be performed to determine how much cancer is present, and if the cancer has spread from the colon or rectum to other parts of the body. This is called staging, and is an important step toward planning a treatment program. The stages for colorectal cancer are as follows:
|Stage 0 (Cancer in Situ)
||The cancer is found in the innermost lining of the colon or rectum.|
|Stage I (also called Dukes’ A colon cancer)
||The cancer has spread beyond the innermost lining of the colon or rectum to the second and third layers. The cancer has not spread to the outer wall or outside of the colon or rectum.|
|Stage II (also called Dukes’ B colon cancer)
||The cancer has spread outside the colon to nearby tissue. However, the lymph nodes are not involved.|
|Stage III (also called Dukes’ C colon cancer)
||The cancer has spread to nearby lymph nodes, but has not spread to other organs in the body.|
|Stage IV (also called Dukes’ D colon cancer)
||The cancer has spread to other parts of the body, such as lungs.|
Specific treatment for colorectal cancer will be determined by your physician based on:
- your age, overall health, and medical history
- extent and location of the disease
- results of certain lab tests
- your tolerance for specific medications, procedures, or therapies
- expectations for the course of this disease
- your opinion or preference
After the colorectal cancer is diagnosed and staged, your physician will recommend a treatment plan. Treatment may include:
- colon surgery
Often, the primary treatment for colorectal cancer is an operation in which the cancer and a length of normal tissue on either side of the cancer are removed, as well as the nearby lymph nodes.
- radiation therapy
Radiation therapy is the use of high-energy radiation to kill cancer cells and to shrink tumors. There are two ways to deliver radiation therapy, including the following:
- external radiation (external beam therapy) - a treatment that precisely sends high levels of radiation directly to the cancer cells. The machine is controlled by the radiation therapist. Since radiation is used to kill cancer cells and to shrink tumors, special shields may be used to protect the tissue surrounding the treatment area. Radiation treatments are painless and usually last a few minutes.
- internal radiation (brachytherapy, implant radiation) - radiation is given inside the body as close to the cancer as possible. Radioactive material is placed next to or directly into the cancer, which limits the effects on surrounding healthy tissue. Some of the radioactive implants are called “seeds” or “capsules."
Internal radiation involves giving a higher dose of radiation in a shorter time span than with external radiation. Some internal radiation treatments stay in the body temporarily. Other internal treatments stay in the body permanently, though the radioactive substance loses its radiation within a short period of time. In some cases, both internal and external radiation therapies are used.
Chemotherapy is the use of anticancer drugs to treat cancerous cells. In most cases, chemotherapy works by interfering with the cancer cell’s ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells. The oncologist will recommend a treatment plan for each individual. Studies have shown that chemotherapy after surgery may increase the survival rate for patients with some stages of colon cancer. It can also be helpful before or after surgery for some stages of rectal cancer. Chemotherapy can also help slow the growth or relieve symptoms of advanced cancer.
- targeted therapy - Newer medications called targeted therapies may be used along with chemotherapy or sometimes by themselves. For example, some newer medications target proteins that are found more often on cancer cells than on normal cells. These medications have different (and often milder) side effects than standard chemotherapy medications and may help some people live longer.
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Last reviewed: 1/28/2013