Colorectal Cancer Symptoms and Risks

Colorectal cancer often starts as polyps or small growths in the colon or rectum. These abnormal growths are common and often don’t turn into cancer. Doctors can’t predict which polyps will turn into cancer, so the American Cancer Society has established guidelines for people age 45 and over to have regular colorectal screenings.

Regular colon cancer screening helps prevent colorectal cancer by finding and removing precancerous polyps before they turn into cancer. Screening can also help detect colorectal cancer early, while it’s still small and before it’s spread.

Colorectal cancer symptoms vary depending on the stage of the cancer. Often, colon cancer shows no symptoms in its early stages. Colon cancer symptoms that you may notice as the disease progresses or becomes severe can include:

• A change in your bowel habits, such as diarrhea, constipation or a feeling that your bowels are not emptying completely
• Blood in your stool or very dark, tarry-looking stools
• Pain in your belly (very late stage)

These symptoms are common and not unique to colon cancer, which is why doctors recommend screening. The potential for a colon cancer diagnosis becomes more likely when age is a factor, or when symptoms persist or keep coming back after colorectal cancer treatment.

In some cases, colon cancer can lead to bowel obstruction, which is a blockage that prevents digestive waste from moving through the colon properly. Symptoms of a bowel obstruction include:

• Constipation
• Not being able to pass gas or empty your bowels
• Noticeable swelling or bloating of the abdomen
• Abdominal cramps that come and go
• Severe abdominal pain
• Loss of appetite
• Vomiting

There are numerous possible risk factors for colon cancer, many of which cannot be controlled:

• Being age 45 or older
• Having a strong family history of colon or rectal cancer (two generations, with one getting the disease before age 50)
• A past history of colon cancer
• Having another type of cancer, such as cancer of the ovary or uterine cancer
• Having polyps removed from your colon, especially if you had large polyps or a large number of polyps
• Having ulcerative colitis or Crohn’s disease for more than 10 years
• Having radiation therapy in your abdomen or pelvis
• Having type 2 diabetes
• Being African-American carries a higher risk of colon cancer
• Having Lynch syndrome 

Other risk factors for colon cancer are directly related to lifestyle choices, such as being overweight. You may be able to lower your risk of developing colorectal cancer by making some simple lifestyle changes:

• Maintain a healthy weight
• Limit alcohol use
• Eat more fruits, vegetables and whole grains
• Eat less red meat and processed meat
• Exercise regularly
• Don’t smoke

Your risk for colon cancer is connected with your weight, diet and how much you exercise. These are risk factors for many cancers, but the link is stronger for colon cancer than for other types of cancer.