Colorectal Cancer

Colorectal cancer occurrence rates are highest among blacks; intermediate among whites, Asians, and Pacific Islanders; and lowest among American Indians, Alaskan Natives, and Hispanics.¹

A risk factor is anything that increases your chance of getting a disease such as cancer. Risk factors for getting colorectal cancer include:

Your age

Everyone who is older than 50 has a risk of getting colorectal cancer and the older you are, the greater the risk. Most cases of colorectal cancer are diagnosed in people older than 50. Most people who get colorectal cancer have no other risk factors besides being older than 50.

Your family's medical history

You are more likely to get colorectal cancer if one of your parents, brothers, sisters, or children has had the disease. Your risk depends on how old your family member was when he or she was diagnosed and on how many members of your family have had the disease.¹

If you have a strong family history of colorectal cancer, you may want to have a blood test to look for changed genes. Genetic mutations are more common in certain ethnic groups, such as Ashkenazi Jews (Jews whose ancestors were from Eastern Europe).

You have a strong family history if all of the following are true:

• You have at least three relatives who have had colon cancer, and at least one of them is a parent, brother, or sister.
• Those relatives are spread over two generations in a row (for example, a grandparent and a parent).
• One of those relatives got cancer before age 50.

The most common gene changes occur in two conditions: familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC). Many people with these changed genes will develop colorectal cancer if they are not carefully watched. Genetic testing can tell you whether you carry a changed, or mutated, gene that can cause FAP or HNPCC.

Most people who get colorectal cancer do not have a personal or family history of the disease.

Your medical history

Your chances of getting colorectal cancer are higher if you have had:

• Colorectal cancer in the past.
• Another type of cancer, such as cancer of the ovary, cancer of the endometrium, or breast cancer.
• Polyps removed from your colon, especially if you had large polyps or a large number of polyps.
• Ulcerative colitis or Crohn's disease for more than 10 years.
• Radiation therapy in your abdomen or pelvis.
• Type 2 diabetes.^{3, 4}

What you eat

Your chances of getting colorectal cancer may be higher if your diet is high in calories, protein, and fat—especially animal fat—and if your diet is low in calcium.

Whether you smoke

Studies show that smokers have a greater chance of getting colorectal cancer.²

How much you exercise

If you are not physically active, you have a greater chance of getting colorectal cancer.

How much you weigh

If you are very overweight, your chances of getting colorectal cancer are higher. Having extra fat in the waist area is a greater risk than having extra fat in the hips or thighs.

How much alcohol you drink

People who drink more than 2 alcoholic drinks a day—and especially those who drink more than 3 drinks a day—have a slightly higher risk for colorectal cancer.⁵