Cancer of the colon or rectum is also called colorectal cancer. In the United States, it is the fourth most common cancer in men and women. Caught early, it is often curable.

It is more common in people over 50, and the risk increases with age. You are also more likely to get it if you have

Polyps - growths inside the colon and rectum that may become cancerous
A diet that is high in fat
A family history or personal history of colorectal cancer
Ulcerative colitis or Crohn's disease

Symptoms can include blood in the stool, narrower stools, a change in bowel habits and general stomach discomfort. However, you may not have symptoms at first, so screening is important. Everyone who is 50 or older should be screened for colorectal cancer. Treatments include surgery, chemotherapy, radiation or a combination.

Colon cancer, often referred to as colorectal cancer, is the cancer in the large intestine or the rectum. The most common types of colon cancers are those caused by carcinomas. Other rare forms of colon cancer include lymphomas, carcinoid tumors, melanomas, and sarcomas. This is the most common form of GI cancer in the US.

Risk factors

Age, diet, and lifestyle are the primary risk factors for colon cancer. The disease has been found in people who are:

50 years old or older
With a family history of cancers in the colon or rectum
A personal history of growths in the colon
A family or personal history of other cancers (breast, endometrial, ovarian)
A history of ulcerative colitis
Hereditary conditions like familial adenomatous polyposis and hereditary nonpolyposis colon cancer

Colon cancer may be associated with a high-fat, low fiber diet and red meat consumption. Smoking cigarettes is another risk factor for colon cancer.

Signs and symptoms

Early signs and symptoms include body malaise and fatigue. Other signs and symptoms may be results of bowel obstruction and in later cases, due to the spread of the cancer to adjacent organs like the bladder, prostate, ureters, vagina and sacrum, and even to the liver. Later signs and symptoms include:

Abdominal pain and tenderness in the lower abdomen
Blood in the stool
Change in bowel habits (diarrhea, constipation)
narrower stools
weight loss
pallor
liver enlargement
widening of the lymph vessels

Diagnosis

Only a tumor biopsy can verify colon cancer. For people 50 years old or older the American Cancer Society recommends fecal occult blood tests and flexible sigmoidoscopy. A digital rectal exam can detect the presence of nearly 15% of colorectal cancers and can be used to detect suspicious rectal and perianal lesions. A fecal occult blood test is important in determining the presence of blood in stool, which is a warning sign for rectal cancer. Proctoscopy or sigmoidoscopy may be done to visualize the GI tract and can detect up to two-thirds of colorectal cancers. A colonoscopy can permit visualization of the colon and allows the retrieval of tissue samples for biopsy.

Treatment

The most effective form of treatment is surgery to remove the affected portions. Chemotherapy and radiation therapy are used in conjunction with surgery to shrink tumors, prevent metastasis, destroy tumors which are inoperable, or treat residual cancer.

Prognosis

Prognosis depends on the overall health of the client, the stage of metastasis and the effectiveness of treatment done. When the cancer is treated at its earlier stages a majority of patients may live 5 years past their diagnosis, called the five-year survival rate. However, this rate drops significantly once the cancer has spread.

Prevention

Diet and lifestyle modifications are essential for people who are at risk. Regular screening for at-risk patients is also important. Fortunately, the death rate for colon cancer has dropped in the last 15 years, a fact attributed to increased screening and earlier detection and treatment.

Understanding Colon Cancer Recommended Resources:

UConn Health Center

Massachusetts Institute of Technology