Cancer of the Colon and Rectum

Introduction

The diagnosis of cancer of the colon or rectum, also called colorectal cancer, raises many questions and a need for clear, understandable answers. Together, cancers of the colon and rectum are among the most common cancers in the United States. They occur in both men and women and are most often found among people who are over the age of 50. Cancer research has led to real progress against colorectal cancer--a lower chance of death and an improved quality of life for people with this disease.

Understanding the Cancer Process

We have already seen from the previous articles related to cancer that all cancerous disorders affect our cells, the body's basic unit of life. To understand cancer better, let us once again refresh our memories with some fundamental science related cancers. The body is made up of many types of cells. Normally, cells grow, divide, and produce more cells, as they are needed to keep the body healthy and functioning properly. Sometimes, however, the process goes out of control and cells keep dividing when new cells are not needed. The mass of extra cells forms a growth or tumor. Tumors can be either benign or malignant.

To begin with, the turning point of such excess cell division, tumors are not cancer. They often can be removed and, in most cases, they do not come back. Unfortunately, a very early detection of most of the tumor growth is still a difficult task for scientific community. Cells in benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely a threat to life.

Malignant tumors are cancer. Cells in malignant tumors are abnormal and divide without control or order. These cancer cells can invade and destroy the tissue around them. Cancer cells can also break away from a malignant tumor. They may enter the bloodstream or lymphatic system (the tissues and organs that produce and store cells that fight infection and disease). This process, called metastasis is how cancer spreads from the original (primary) tumor to form new (secondary) tumors in other parts of the body.

The Colon and Rectum

The colon and rectum are parts of the body's digestive system, which removes nutrients from food and stores waste until it passes out of the body. Together, the colon and rectum form a long, muscular tube called the large intestine (also called the large bowel). The colon is the first 6 feet of the large intestine, and the rectum is the last 8 to 10 inches.

Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancers affecting either of these organs may also be called colorectal cancer.

Though the exact cause of any of these cancers are not yet known, several studies so far conducted have shown that certain risk factors increase a person's chances of developing colorectal cancer.

Age has turned out to be a crucial factor. Colorectal cancer is more likely to occur, as people get older. This disease is more common in people over the age of 50. However, the percentage of colorectal cancer among younger ages, are at a rise in recent years.

Diet is one of the pivotal factors that are responsible for the occurrence of this type of disorders among teenagers and human subjects at younger ages. Colorectal cancer seems to be associated with diets that are high in fat and calories and low in fiber. Several research groups are at present actively involved in gathering additional information to correlate the type of food intake and chances of falling into the risk categories with colorectal cancers.

Interestingly enough family medical history is lot of significance in the occurrence of colorectal cancers. Polyps are benign growths on the inner wall of the colon and rectum. They are fairly common in people over age fifty. Some types of polyps increase a person's risk of developing colorectal cancer. Researchers have also shown that women with a history of cancer of the ovary, uterus, or breast have a somewhat increased chance of developing colorectal cancer. First-degree relatives (parents, siblings, children) of a person who has had colorectal cancer are somewhat more likely to develop this type of cancer themselves, especially if the relative had the cancer at a young age. Ulcerative colitis. Ulcerative colitis is a condition in which the lining of the colon becomes inflamed. Having this condition increases a person's chance of developing colorectal cancer.

Colorectal Cancer: Can we reduce the risk?

Research shows that colorectal cancer develops gradually from benign polyps. Early detection and removal of polyps may help to prevent colorectal cancer. Studies are looking at smoking cessation, use of dietary supplements, use of aspirin or similar medicines, decreased alcohol consumption, and increased physical activity to see if these approaches can prevent colorectal cancer. Some studies suggest that a diet low in fat and calories and high in fiber can help prevent colorectal cancer.

Detecting Cancer Early!

A few of the tests that might help to detect colorectal cancer. A fecal occult blood test (FOBT) is a test used to check for hidden blood in the stool. Sometimes cancers or polyps can bleed, and FOBT is used to detect small amounts of bleeding. A sigmoidoscopy is an examination of the rectum and lower colon (sigmoid colon) using a lighted instrument called a sigmoidoscope. A colonoscopy is an examination of the rectum and entire colon using a lighted instrument called a colonoscope. A double contrast barium enema (DCBE) is a series of x-rays of the colon and rectum. The patient is given an enema with a solution that contains barium, which outlines the colon and rectum on the x-rays. A digital rectal exam (DRE) is an exam in which the doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas.

Symptoms of Colorectal Cancer

Common signs and symptoms of colorectal cancer include:

  1. A change in bowel habits
  2. Diarrhea, constipation, or feeling that the bowel does not empty completely
  3. Blood (either bright red or very dark) in the stool
  4. Stools that are narrower than usual
  5. General abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps)
  6. Weight loss with no known reason
  7. Vomiting

Stages of Colorectal Cancer

Stage 0. The cancer is very early. It is found only in the innermost lining of the colon or rectum.

                              Stage I. The cancer involves more of the inner wall of the colon or rectum.

 

Stage II. The cancer has spread outside the colon or rectum to nearby tissue, but not to the lymph nodes. (Lymph nodes are small, bean-shaped structures that are part of the body's immune system.)

Stage III. The cancer has spread to nearby lymph nodes, but not to other parts of the body.

Stage IV. The cancer has spread to other parts of the body. Colorectal cancer tends to spread to the liver and/or lungs.

Treatment for Colorectal Cancer

Several different types of treatment are used to treat colorectal cancer. Surgery to remove the tumor is the most common treatment for colorectal cancer. Generally, the surgeon removes the tumor along with part of the healthy colon or rectum and nearby lymph nodes. Normally, the doctor is able to legate the healthy portions of the colon or rectum. When the surgeon cannot reconnect the healthy portions, a colostomy is necessary. Colostomy, a surgical opening (stoma) through the wall of the abdomen into the colon, provides a new path for waste material to leave the body. After a colostomy, the patient wears a special bag to collect body waste.

Chemotherapy may be given to destroy any cancerous cells that may remain in the body after surgery, to control tumor growth, or to relieve symptoms of the disease. Most of the anticancer drugs are given in the form of an intravenous infusion (IV) or rarely as a pill.

Radiation therapy, involves the use of high-energy x-rays to kill cancer cells. Radiation therapy is a local therapy, meaning that it affects the cancer cells only in the treated area. Most often it is used in patients whose cancer is in the rectum. The radiation may come from a machine (external radiation) or from an implanted vehicle (a small container of radioactive material) placed directly into or near the tumor (internal radiation).

Side Effects of Chemotherapy

Most often the side effects are temporary. Surgery causes short-term pain and tenderness in the area of the operation, temporary constipation or diarrhea. Patients who have a colostomy may have irritation of the skin around the stomach. Common side effects of chemotherapy include nausea and vomiting, hair loss, mouth sores, diarrhea, and fatigue. Less often, serious side effects may occur, such as infection or bleeding. Common side effects of radiation therapy are fatigue, skin changes at the site where the treatment is given, loss of appetite, nausea, and diarrhea. Sometimes, radiation therapy can cause bleeding through the rectum (bloody stools).

The Importance of Follow-up Care

Follow-up cares after treatment for colorectal cancer is important. Checkups may include a physical exam, a fecal occult blood test, a colonoscopy, chest x-rays, and lab tests.

HARRY KOCHAT
BioNumerik Pharmaceuticals Inc.
(An oncology based company based in San Antonio, Texas, USA)


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