Aspirin may prevent recurrence of stage III colon cancer

Report from the 2005 annual meeting of the American Society of Clinical Oncology

Patients enrolled in chemotherapy clinical trial who reported consistent aspirin use had about half the recurrences of those who did not take aspirin. Patients filled out questionnaires about aspirin use midway through the 6 month chemo trial and 6 months afterwards. Those who said they were taking aspirin on both questionnaires were labeled consistent users. Their recurrence rates, disease-free-survival, and survival were compared to the group who reported no aspirin use.

Of 830 patients, 72 or 8.7 percent were consistent aspirin users.

It was not possible to tell from the data whether or not the aspirin dose made a difference, although the research team found no reason to believe that it did. The study found a similar, but slightly smaller, reduction in recurrence risk for users of either celecoxib (Celebrex) or roxecoxib (Vioxx). There was no risk reduction for those taking acetaminophen (Tylenol.)

Charles Fuchs MD reported the study results at ASCO 2005.

Conclusions: Consistent aspirin use may be associated with improved outcome in patients with stage III colon cancer

Read the ASCO meeting abstract with a link to Dr. Fuch's presentation.

Low-dose aspirin taken every other day does not appear to reduce colorectal cancer in women

A randomized study of nearly 40,000 women found that 100 mg. of aspirin taken every other day did not prevent colorectal cancer or reduce death from colorectal cancer. Twenty thousand women in the Women's Health Study received 100 mg of aspirin every other day for over 10 years. Another 20,000 were randomly selected to take a placebo pill. Neither the women nor their doctors knew which pill an individual woman was taking.

Researchers found no difference in the number of cases of of colorectal cancer between the aspirin or placebo groups, nor was there any difference in colorectal cancer deaths. When incidence of colorectal cancer by site (colon or rectum) or stage (Dukes A, B, C, or D) was studied, numbers and percentages of cancers were similar in both groups.

There were no differences between the two groups in self-reported colon polyps nor in the use of colonoscopy or sigmoidoscopy to screen for cancer.

Overall, aspirin made no difference in cancer cases or in cases of breast cancer. There was a trend toward reduced risk for lung cancer and deaths from lung cancer.

Over the 10 years 2,865 women were diagnosed with cancer, 269 with colorectal cancer. Of the new cases, 43% were breast and 9% were colorectal cancer.

It is possible that a higher dose of aspirin might reduce the risk of cancer overall and colorectal cancer in particular, but the researchers pointed out that randomized trials would be necessary to determine that and that, "Such data would need to be considered in the context of risk of gastrointestinal advserve effects before recommending higher dose aspirin for cancer chemoprevention for low-risk individuals."

Over all the Women's Health Study research team concluded:

"Results from this large-scale, long-term trial suggest that alternate day use of low-dose aspirin (100 mg) for an average 10 years of treatment does not lower risk of total, breast, colorectal, or other site-specific cancers. A protective effect on lung cancer or a benefit of higher doses of aspirin cannot be ruled out"

The study was published in the July 6, 2005 issue of the Journal of the American Medical Association

Read the full text article in the Journal of the American Medical Association.

Read an article about the study in USA Today.

Read the Reuters article about the research results.