skip banner navigation
National Cancer Institute
NCI Home Cancer Topics Clinical Trials Cancer Statistics Research & Funding News About NCI

Clinical Trial Results

Summaries of Newsworthy Clinical Trial Results

< Back to Main

    Posted: 04/09/2002
Page Options
Print This Page  Print This Page
E-Mail This Document  E-Mail This Document
Search by Cancer Type
Breast Cancer

Lung Cancer

Prostate Cancer

More Results
Search Results

    Go  
Quick Links
Dictionary
Cancer-related terms

Funding Opportunities
Research and training

NCI Publications
Order/download free booklets

NCI Calendar
Scientific meetings

Español
Informacion en español
NCI Highlights
Chemo Extends Life in Advanced Prostate Cancer

Temozolomide Plus Radiation Helps Brain Cancer

Confirmed: Raloxifene Drops Risk of Breast Cancer

Bortezomib Delays Progression of Multiple Myeloma

Annual Report to the Nation

Past Highlights
Need Help?
Related Pages
Colon and Rectal Cancer Home Page
NCI's gateway for information about colon and rectal cancer.
Aspirin May Reduce Risk of Colon Polyps

Key Words: adenoma, aspirin, colon, precancerous polyps. (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary.)

A daily baby aspirin reduced by 19 percent the risk that precancerous polyps (adenomas) in the colon would recur in patients who'd had a previous adenoma surgically removed, researchers reported April 7, 2002, at the American Association for Cancer Research annual meeting in San Francisco. Adenomas are early signs of abnormal colon growth that can progress to colorectal cancer. [Editor's note: The results of this study were subsequently published. See NCI-Funded Clinical Trials Show Aspirin Reduces Recurrence of Polyps.]

In patients with advanced adenomas or colorectal cancer, the same daily low-dose aspirin -- 80 milligrams -- reduced the risk of advanced adenoma recurrence by 40 percent.

A daily aspirin dose of 325 milligrams had a lesser preventive effect, according to the researchers, reducing the overall risk of adenoma recurrence by 4 percent and the risk of recurrence of advanced adenomas and colorectal cancers by 19 percent.

"We conclude that aspirin may have a modest chemopreventive effect in the large bowel, apparently more marked for lower-dose aspirin," said John A. Baron, M.D., professor of medicine at Dartmouth Medical School in Lebanon, N.H., who led the research group that conducted the study.

This is the first clinical trial to show that aspirin has a preventive effect on the process of colorectal cancer development, said Ernest Hawk, M.D., chief of the gastrointestinal and other cancers research group at the National Cancer Institute in Bethesda, Maryland.

"These results suggest that Americans who are already taking a daily low-dose aspirin to reduce their risk of a heart attack or stroke may be getting an additional benefit -- a reduced risk of colorectal cancer -- without being aware of it," Hawk said.

Daily low-dose aspirin may be an appropriate supplement to regular screening procedures for colorectal cancer in individuals who are at moderate risk for the disease because they have had a prior adenoma, Hawk said. However, he added, it is premature to recommend aspirin to reduce the risk of colorectal cancer in all Americans over age 50. People in this age group are at mildly elevated risk for the disease because of their age alone.

The current study involved 1,121 patients who were randomly assigned to take 80 milligrams of aspirin (one baby aspirin), 325 milligrams of aspirin (one standard aspirin), or a placebo (dummy pill) daily. Patients were screened for recurrent adenomas with a follow-up colonoscopy (examination of the colon) a minimum of one year after entering the study. The average time to this follow-up was 34 months. Patients were eligible for the study if they had had at least one adenoma removed within the preceding three months, had no known cardiovascular disease or other conditions usually treated with aspirin, and had no hereditary cancer syndromes.

The new study confirms a large, consistent body of evidence from observational studies and animal models that aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) can reduce the incidence of colorectal adenomas and colorectal cancer deaths. The finding that aspirin reduced recurrence of advanced adenomas strongly suggests, Hawk said, that the drug may be significantly slowing progression of these precancerous tumors.

However, the finding that a low dose of aspirin had a greater preventive effect than a standard dose is unexpected, Hawk added. The study results will have to be analyzed carefully for a possible explanation.

Colorectal cancer is the second leading cause of death from cancer in the United States. An estimated 56,600 Americans will die from the disease this year. Roughly a third of those deaths could be avoided by regular screening tests to detect and remove adenomas before they turn into cancer. Several types of tests can be used, alone or in combination, to screen for colorectal cancer. Regular screening is recommended for all Americans aged 50 and older, and earlier if family members have a history of colorectal adenomas or cancer.

Back to TopBack to Top

skip footer navigation

A Service of the National Cancer Institute
Department of Health and Human Services National Institutes of Health FirstGov.gov