Colorectal Cancer Prevention and Early Detection

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Importance of colorectal cancer screening

Regular colorectal cancer screening or testing is one of the most powerful weapons for preventing colorectal cancer. Excluding skin cancers, colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. Overall, the lifetime risk for developing colorectal cancer is about 1 in 20 (5%).

Colorectal cancer is the third leading cause of cancer-related deaths in the United States when men and women are considered separately, and the second leading cause when both sexes are combined.

The incidence rate (the number of cases per 100,000 people per year) of colorectal cancer has been dropping for about the last 20 years. This is thought to be in large part due to screening (looking for cancer in people who have no symptoms of the disease). Colorectal screening tests can also find polyps, which can be removed before they can develop into cancers.

It can take many years (as many as 10 to 15) for a polyp to develop into colorectal cancer. Regular screening can prevent many cases of colorectal cancer altogether by finding and removing certain types of polyps before they have the chance to turn into cancer. Screening can also find colorectal cancer early, when it is highly curable.

The relative 5-year survival rate for colorectal cancer when diagnosed at an early stage before it has spread is about 90%. But only about 4 out of 10 colorectal cancers are found at that early stage. When cancer has spread outside the colon, survival rates are lower.

(The 5-year observed survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed; it includes people with colorectal cancer who may die of other causes, such as heart disease. Five-year relative survival rates assume that some people will die of other causes and compare the observed survival with that expected for people without the cancer. This is a better way to see the impact of the cancer on survival.)

Not only does colorectal cancer screening save lives, but it also is cost effective. Studies have shown that the cost-effectiveness of colorectal screening is consistent with many other kinds of preventive services and is lower than some common interventions. It is much less expensive to remove a polyp during screening than to try to treat advanced colorectal cancer. With sharp cost increases possible as new treatments become standards of care, screening is likely to become even more cost effective.

Unfortunately, only about half of people eligible for colorectal cancer screening, get the tests that they should. This may be due to lack of public and health professional awareness of screening options, financial barriers, and inadequate health insurance coverage and/or benefits.

See the section “Colorectal cancer screening tests” for more information about the tests used to screen for colorectal cancer. The section “American Cancer Society recommendations for colorectal cancer early detection” has our guidelines for using these tests to find colorectal cancer and polyps..


Last Medical Review: 10/15/2014
Last Revised: 10/29/2014