Colorectal cancer is a major health concern and public health problem in

most of the Western countries despite widespread use of screening technique

to detect early stages of this disease. In the United States alone more than

148,000 people are diagnosed with colorectal cancer each year. Over 55,000

deaths occur in the United States due to colorectal cancer. Colon cancer is

a very common disease and it is the third most common type of cancer in both

sexes. In men it ranks third after prostate and lung cancer and in women

after lung and breast cancer. Colorectal cancer ranks second after lung

cancer in terms of number of deaths from cancer.

Majority of colorectal cancers (72%) start in the colon and smaller fraction

(28%) arises in the rectum. The lifetime risk of being diagnosed with

colorectal cancer in the United States is 5.9% for men and 5.5% for women.

There are several known risk factors for colorectal cancer. Being a male

poses higher risk of colorectal cancer compared to being female. Increasing

age is associated with an increase in the risk of colorectal cancer.

Incidence of colorectal cancer is higher among African Americans compared to

Caucasians. Risk of developing colorectal cancer is much higher for people

living in the industrialized nations compared to less industrialized

nations.

Diet, rich in fat and cholesterol, is linked to higher risk of developing

colorectal cancer. Lack of proper exercise, presence of inflammatory bowel

disease, some types of polyps and history of family members with diagnosis

of colorectal cancer have been associated with higher risk of development of

colorectal cancer.

Early stages of colorectal cancer may not cause any symptoms. Some people

might experience vague symptoms like mild abdominal pain, flatulence or

diarrhea. Occasionally there might be microscopic bleeding and the diagnosis

of colorectal cancer would be suspected because of presence of anemia from

chronic bleeding. Some people might develop frank bleeding or symptoms of

bowel obstruction.

Screening for colorectal cancer can detect the disease at an early stage. A

rectal examination and examination of the stool specimen for the presence of

microscopic quantity of blood are very common screening tools. Sigmoidocopy

and colonoscopy are more invasive investigations, which can detect and

remove some polyps that might be precursors of cancer. Less invasive

techniques like barium enema, virtual colonoscopy using a CT scan machine

are also often used in screening and diagnosis of colorectal cancer. Adults

having an average risk of colorectal cancer should start colorectal cancer

screening beginning at age 50.

Treatment of colorectal cancer depends upon the stage of the disease. Early

stages of colorectal cancers are treated with surgery alone, later stages of

colorectal cancer are treated with surgery followed by chemotherapy with or

without radiation treatment. Rectal cancers are more often treated with

radiation therapy compared to colon cancer. Advanced stages of colorectal

cancer, where the disease has spread to other organs, are usually treated

with chemotherapy alone. There are several new chemotherapeutic agents and

biological drugs available for the treatment of colorectal cancer. Treatment

of colorectal cancer has undergone marked changes in the last 10 years. The

newer drugs are showing much improved efficacy and prolonging life

expectancy in patients with advanced stage colorectal cancer.