Colon Cancer Risk Factors

What is cancer?

Every day within our bodies, a massive process of destruction and repair occurs. The human body is comprised of about fifteen trillion cells, and every day billions of cells wear out or are destroyed. In most cases, each time a cell is destroyed the body makes a new cell to replace it, trying to make a cell that is a perfect copy of the cell that was destroyed because the replacement cell must be capable of performing the same function as the destroyed cell. During the complex process of replacing cells, many errors occur. Despite remarkably elegant systems in place to prevent errors , the body still makes tens of thousands of mistakes daily while replacing cells either because of random errors or because there are outside pressures placed on the replacement process that promote errors. Most of these mistakes are corrected by additional elegant systems or the mistake leads to the death of the newly made cell, and another normal new cell is produced. Sometimes a mistake is made, however, and is not corrected. Many of the uncorrected mistakes have little effect on health, but if the mistake allows the newly made cell to divide independent of the checks and balances that control normal cell growth, that cell can begin to multiply in an uncontrolled manner. When this happens a tumor (essentially a mass of abnormal cells) can develop.

Tumors fall into two categories; there are benign tumors and malignant (cancerous) tumors. So what is the difference? The answer is that a benign tumor grows only in the tissue from which it arises. Benign tumors sometimes can grow quite large or rapidly and cause severe symptoms, even death, although most do not. For example, a fibroid tumor in a woman's uterus can cause bleeding or pain, but it will never travel outside the uterus and grow as a new tumor elsewhere. Fibroids, like all benign tumors, lack the capacity to shed cells into the blood and lymphatic system, so they are unable to travel to other places in the body and grow. A cancer, on the other hand, can shed cells that can float like dandelion seeds in the wind through the blood or lymphatic system, landing in tissues distant from the primary tumor and growing into new tumors in these distant tissues. This process of spreading to distant tissues, called metastasis, is the defining characteristic of a cancerous tumor.

Cancer often is referred to as a single entity, but in fact, it is a group of more than 100 different diseases, much like infectious diseases. Cancers are named by the tissues from which the first tumor arises. Hence, a lung cancer that travels to the liver is not a liver cancer but is described as lung cancer metastatic to the liver, and a breast cancer that spreads to the brain is not described as a brain tumor but rather as breast cancer metastatic to the brain. Each cancer is a different disease with different treatment options and varying prognoses (likely outcomes). In fact, each individual with cancer has a unique disease, and the relative success or lack thereof of treatment among patients with the same diagnosis may be very different. As a result, it is important to treat each person with a diagnosis of cancer as an individual regardless of the type of cancer

Colon cancer facts

• Colorectal cancer is a malignant tumor arising from the inner wall of the large intestine.
• Colorectal cancer is the third leading cause of cancer in malesand fourth in females in the U.S.
• Risk factors for colorectal cancer include heredity, colon polyps, and long-standing ulcerative colitis.
• Most colorectal cancers develop from polyps. Removal of colon polyps can prevent colorectal cancer.
• Colon polyps and early cancer can have no symptoms. Therefore regular screening is important.

• Diagnosis of colorectal cancer can be made by barium enema or by colonoscopy with biopsy confirmation of cancer tissue.
• Treatment of colorectal cancer depends on the location, size, and extent of cancer spread, as well as the health of the patient.
• Surgery is the most common treatment for colorectal cancer.
• Chemotherapy can extend life and improve quality of life for those living with colorectal cancer.

No one knows the exact causes of colon cancer. Doctors often cannot explain why one person develops this disease and another does not. However, it is clear that colon cancer is not contagious. No one can catch this disease from another person.

Research has shown that people with certain risk factors are more likely than others to develop colon cancer. A risk factor is something that may increase the chance of developing a disease.

Studies have found the following risk factors for colon cancer:

Age over 50: colon cancer is more likely to occur as people get older. More than 90 percent of people with this disease are diagnosed after age 50. The average age at diagnosis is 72.

colon polyps: Polyps are growths on the inner wall of the colon or rectum. They are common in people over age 50. Most polyps are benign (not cancer), but some polyps (adenomas) can become cancer. Finding and removing polyps may reduce the risk of colon cancer.

Family history of colon cancer: Close relatives (parents, brothers, sisters, or children) of a person with a history of colon cancer are somewhat more likely to develop this disease themselves, especially if the relative had the cancer at a young age. If many close relatives have a history of colon cancer, the risk is even greater.

Genetic alterations: Changes in certain genes increase the risk of colon cancer.

Hereditary nonpolyposis colon cancer (HNPCC) is the most common type of inherited (genetic) colon cancer. It accounts for about two percent of all colon cancer cases. It is caused by changes in an HNPCC gene. Most people with an altered HNPCC gene develop colon cancer, and the average age at diagnosis of colon cancer is 44.

Familial adenomatous polyposis (FAP) is a rare, inherited condition in which hundreds of polyps form in the colon and rectum. It is caused by a change in a specific gene called APC. Unless FAP is treated, it usually leads to colon cancer by age 40. FAP accounts for less than one percent of all colon cancer cases.

Family members of people who have HNPCC or FAP can have genetic testing to check for specific genetic changes. For those who have changes in their genes, health care providers may suggest ways to try to reduce the risk of colon cancer, or to improve the detection of this disease. For adults with FAP, the doctor may recommend an operation to remove all or part of the colon and rectum.

Personal history of cancer: A person who has already had colon cancer may develop colon cancer a second time. Also, women with a history of cancer of the ovary, uterus (endometrium), or breast are at a somewhat higher risk of developing colon cancer.

Ulcerative colitis or Crohn's disease: A person who has had a condition that causes inflammation of the colon (such as ulcerative colitis or Crohn's disease) for many years is at increased risk of developing colon cancer.

Diet and Lifestyle: Studies suggest that diets high in red meat and fat (especially animal fat) and low in calcium, folate, and fiber may increase the risk of colon cancer. Also, some studies suggest that people who eat a diet very low in fruits and vegetables may have a higher risk of colon cancer. However, results from diet studies do not always agree, and more research is needed to better understand how diet affects the risk of colon cancer.

Inactivity and obesity have also been linked to higher risk of colon cancer. Studies have shown that daily physical activity can decrease colon cancer risk by as much as 50 percent.

Cigarette smoking: A person who smokes cigarettes may be at increased risk of developing polyps and colon cancer.

Because people who have colon cancer may develop colon cancer a second time, it is important to have checkups. If you have colon cancer, you also may be concerned that your family members may develop the disease. People who think they may be at risk should talk to their doctor