Aspirin May Help Treat Colon Cancer

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Aspirin May Help Treat Colon Cancer

Study Shows Aspirin Use Boosts Survival Rate of People With Colon Cancer

By Kelli

WebMD Health News

Reviewed By Louise Chang, MD

Aug. 11, 2009 -- Certain patients with colorectal cancer who begin regular

aspirin use after the disease develops may greatly improve their odds of

survival, researchers in Boston report.

Aspirin is often praised for its anticancer effects. Numerous studies have

suggested that regular aspirin use may help lower the risk of colon polyps and

colorectal cancer. Now, a study published in this week's issue of the Journal of

the American Medical Association is among the first to link aspirin use and

colon cancer survival.

For the study, researchers from Massachusetts General Hospital, Dana-Farber

Cancer Institute, and Brigham and Women's Hospital looked at the link between

aspirin use and survival among 1,279 adults with stage I, II, or III

nonmetastatic colorectal cancer, or cancer that had not spread to distant areas.

The patients had enrolled in two large studies in the 1980s prior to their

cancer diagnosis and agreed to answer questions about their health over the

years. Researchers followed them through June 2008.

In general, study participants who reported aspirin use after being diagnosed

with colorectal cancer had a 29% lower risk of colorectal cancer death and a 21%

lower risk of overall death, compared to non-aspirin users. The researchers note

that the main reasons reported for aspirin use included arthritis,

musculoskeletal pain, and treatment and prevention of cardiovascular disease.

Taking aspirin for the first time after a diagnosis improved a patient's odds

even more. Among the specific study findings:

Patients with colorectal cancer who started regular aspirin use for the first

time after diagnosis had a 47% lower risk of colorectal cancer death and 32%

lower risk of overall death than nonusers of aspirin.

The survival advantage was seen only in those with -2-positive tumors. Most

colorectal tumors are -2-positive.

Aspirin-Resistant Colon Cancer

The study showed that starting regular aspirin use for the first time after a

colorectal cancer diagnosis greatly reduced the risk of colorectal

cancer-related death, but taking aspirin before colorectal cancer developed and

continuing to do so after diagnosis did not significantly influence survival

rates. In other words, former regular aspirin users do not reap as much benefit

as those who are new to regular aspirin use.

That might raise an eyebrow or two, particularly since aspirin use has been

linked to reduced risk of colorectal cancer.

The researchers say the finding suggests that some colorectal cancer tumors may

be resistant to aspirin's effects, while others may be especially susceptible.

Aspirin is believed to block a substance called cyclooxygenase-2 (-2). -2

promotes inflammation and cell growth. If the substance is overexpressed, the

tumor is called -2-positive; tumors that do not overexpress the substance are

called -2-negative tumors.

-2-positive colorectal tumors may be especially sensitive to aspirin's

anticancer effects. In the study, the survival improvements were seen primarily

among those with such tumors. Specifically, patients with -2-positive

colorectal tumors who used aspirin regularly after diagnosis had a 61% lower

risk of colorectal cancer death and 38% lower overall death risk than

non-aspirin users.

Survival in those with the -2-negative tumors did not appear to be affected

by aspirin use.

The new findings could one day lead to aspirin-based therapies for patients with

newly diagnosed, early-stage colorectal cancer. However, the researchers do not

recommend the routine use of aspirin or related medicines for cancer treatment

until further studies are done. Aspirin and other -2 inhibitors can cause

potentially dangerous side effects such as gastrointestinal bleeding.

In an accompanying editorial published in the same journal, Alfred I. Neugut,

MD, PhD, of Columbia University, adds that aspirin-related survival studies

should also be done in patients with metastatic colorectal cancer.

SOURCES: News release, Northwestern University. De Felice, F. Proceedings of the

National Academy of Sciences, Feb. 2, 2009.

©2009 WebMD, LLC. .