Lengthy Aspirin Use Reduces Colorectal Cancer Risk

August 24, 2005

By Michael Smith, MedPage Today Staff Writer

Reviewed by Rubeen K. Israni, M.D., Fellow, Renal-Electrolyte and

Hypertension Division, University of Pennsylvania School of Medicine

August 23, 2005

Also covered by: Forbes, Philadelphia Inquirer (Registration Req.),

USA Today

MedPage Today Action Points

Advise patients that short-term use of aspirin has been shown to

reduce the recurrence of adenoma in people who have been treated for

adenoma or colorectal cancer.

Note that in this study the benefit of aspirin or NSAID use in

preventing colon colorectal cancer only appeared after more than a

decade.

Caution that the doses that appear to be protective are also

associated with a higher risk of serious gastrointestinal bleeding.

Review

BOSTON, Aug. 23-Women who consistently take relatively high weekly

doses of aspirin have a reduced risk of colorectal cancer,

researchers here reported today.

But the benefit only comes after at least 10 years of consistent use

of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) at

doses that may have dangerous side effects, such as gastrointestinal

bleeding.

This finding, derived from the long-running Nurses' Health Study, is

only applicable to women, Andrew Chan, M.D., of Massachusetts General

Hospital here and colleagues reported in the Aug. 24 issue of the

Journal of the American Medical Association. But a 1994 study in the

Annals of Internal Medicine also demonstrated a protective effect in

men.

In patients with colorectal adenoma or cancer, randomized trials have

previously shown that short-term use of aspirin prevents recurrence

of an adenoma, said Dr. Chan.

But the picture has been less clear when it came to primary

prevention of colorectal cancer, the researchers said. At least two

randomized studies have shown no effect, perhaps because follow-up

was not long enough, and the Women's Health Study recently reported

low-dose aspirin -- 100 milligrams every two days -- had no effect.

Indeed, the current 20-year study also showed no effect for low

doses, Dr. Chan said.

" Our study did find a protective effect of long-term aspirin use on

risk of invasive colorectal cancer, but only at dosage levels

considerably higher than those used to prevent cardiovascular

disease, " he said.

The Nurses' Health Study has followed more than 120,000 female

registered nurses since the mid-1970s, studying risk factors for

cancer and cardiovascular disease, including assessments of diet and

the use of aspirin and NSAIDs.

For this study, the researchers analyzed data on nearly 83,000 women

for whom information on aspirin and NSAID use was available over a 20-

year period starting in 1980.

Regular use -- more than two standard 325-milligram tablets a week --

reduced the risk of colorectal cancer by 23%, compared with non-

regular users, the researchers found. The relative risk on

multivariate analysis was 0.77, with a 95% confidence interval of

0.67 to 0.88.

However, the risk reduction did not become statistically significant

until more than 10 years of regular use.

A similar effect was seen for the NSAIDs naproxen and ibuprofen.

The protective effect appeared to be dose-related. Compared with

women who didn't use the drugs, taking:

0.5 to 1.5 standard aspirin tablets per week resulted in a relative

risk for colorectal cancer of 1.10, with a 95% confidence interval of

0.92 to 1.31.

Two to 5 aspirin per week resulted in a relative risk of 0.89, with a

confidence interval ranging from 0.73 to 1.10.

Six to 14 aspirin per week resulted in a relative risk of 0.78, with

the confidence interval from 0.62 to 0.97.

And more than 14 aspirin a week resulted in a relative risk of 0.68,

with the confidence interval from 0.49 to 0.95.

" The most relevant period of use is greater than 10 years in the

past, " the researchers found. If a woman consistently took more than

14 aspirin a week during the earliest decade of the study, her risk

of colorectal cancer was reduced by 53%. The relative risk was 0.47

with a confidence interval of 0.31 to 0.71.

Major gastrointestinal bleeding -- requiring either a blood

transfusion or a hospital stay -- also appeared to be dose-related.

All told, there were 1,687 major GI events; the incidence per 1,000

person-years was:

0.77 among women who denied any aspirin use,

1.07 for women taking 0.5 to 1.5 standard tablets a week,

1.07 for two to five tablets per week,

1.40 for six to 14 aspirin per week,

and 1.57 for more than 14 per week.

The implication, the researchers said, is that " use of aspirin at the

highest-dose category … would prevent one to two cases of colorectal

cancer " at a cost of eight excess episodes of major gastrointestinal

bleeding for every 10,000 person-years.

" We're going to need additional studies that clarify the risks and

benefits " of aspirin use before making firm recommendations, Dr. Chan

said. " For now, individuals need to discuss the options with their

physicians. "

Primary source: Journal of the American Medical Association

Source reference:

Chan AT et al. Long-term Use of Aspirin and Nonsteroidal Anti-

inflammatory Drugs and Risk of Colorectal Cancer. JAMA. 2005; 294:914-

923.

www.CurrencyTrade.FXTrainer.biz

www.EndOfMortgage.com

August 24, 2005

Drinking lots of coffee reduces colo-rectal cancer risk as well, but, then, it increases pancreatic cancer risk. I'm sort of wondering if eating aspirin runs sort of the same way, only, it would increase stomach cancer risk, as well as stomach ulcers.

It would be better to do no harm rather than try to decide what one is going to trade off.

Ed

-

bjohnsonrn

Wednesday, August 24, 2005 10:51 AM

Lengthy Aspirin Use Reduces Colorectal Cancer Risk

Lengthy Aspirin Use Reduces Colorectal Cancer Risk By Michael Smith, MedPage Today Staff WriterReviewed by Rubeen K. Israni, M.D., Fellow, Renal-Electrolyte and Hypertension Division, University of Pennsylvania School of MedicineAugust 23, 2005Also covered by: Forbes, Philadelphia Inquirer (Registration Req.), USA Today MedPage Today Action PointsAdvise patients that short-term use of aspirin has been shown to reduce the recurrence of adenoma in people who have been treated for adenoma or colorectal cancer.Note that in this study the benefit of aspirin or NSAID use in preventing colon colorectal cancer only appeared after more than a decade. Caution that the doses that appear to be protective are also associated with a higher risk of serious gastrointestinal bleeding.ReviewBOSTON, Aug. 23-Women who consistently take relatively high weekly doses of aspirin have a reduced risk of colorectal cancer, researchers here reported today. But the benefit only comes after at least 10 years of consistent use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) at doses that may have dangerous side effects, such as gastrointestinal bleeding. This finding, derived from the long-running Nurses' Health Study, is only applicable to women, Andrew Chan, M.D., of Massachusetts General Hospital here and colleagues reported in the Aug. 24 issue of the Journal of the American Medical Association. But a 1994 study in the Annals of Internal Medicine also demonstrated a protective effect in men. In patients with colorectal adenoma or cancer, randomized trials have previously shown that short-term use of aspirin prevents recurrence of an adenoma, said Dr. Chan. But the picture has been less clear when it came to primary prevention of colorectal cancer, the researchers said. At least two randomized studies have shown no effect, perhaps because follow-up was not long enough, and the Women's Health Study recently reported low-dose aspirin -- 100 milligrams every two days -- had no effect. Indeed, the current 20-year study also showed no effect for low doses, Dr. Chan said. "Our study did find a protective effect of long-term aspirin use on risk of invasive colorectal cancer, but only at dosage levels considerably higher than those used to prevent cardiovascular disease," he said. The Nurses' Health Study has followed more than 120,000 female registered nurses since the mid-1970s, studying risk factors for cancer and cardiovascular disease, including assessments of diet and the use of aspirin and NSAIDs. For this study, the researchers analyzed data on nearly 83,000 women for whom information on aspirin and NSAID use was available over a 20-year period starting in 1980. Regular use -- more than two standard 325-milligram tablets a week -- reduced the risk of colorectal cancer by 23%, compared with non-regular users, the researchers found. The relative risk on multivariate analysis was 0.77, with a 95% confidence interval of 0.67 to 0.88. However, the risk reduction did not become statistically significant until more than 10 years of regular use. A similar effect was seen for the NSAIDs naproxen and ibuprofen. The protective effect appeared to be dose-related. Compared with women who didn't use the drugs, taking: 0.5 to 1.5 standard aspirin tablets per week resulted in a relative risk for colorectal cancer of 1.10, with a 95% confidence interval of 0.92 to 1.31. Two to 5 aspirin per week resulted in a relative risk of 0.89, with a confidence interval ranging from 0.73 to 1.10. Six to 14 aspirin per week resulted in a relative risk of 0.78, with the confidence interval from 0.62 to 0.97. And more than 14 aspirin a week resulted in a relative risk of 0.68, with the confidence interval from 0.49 to 0.95. "The most relevant period of use is greater than 10 years in the past," the researchers found. If a woman consistently took more than 14 aspirin a week during the earliest decade of the study, her risk of colorectal cancer was reduced by 53%. The relative risk was 0.47 with a confidence interval of 0.31 to 0.71. Major gastrointestinal bleeding -- requiring either a blood transfusion or a hospital stay -- also appeared to be dose-related. All told, there were 1,687 major GI events; the incidence per 1,000 person-years was: 0.77 among women who denied any aspirin use, 1.07 for women taking 0.5 to 1.5 standard tablets a week, 1.07 for two to five tablets per week, 1.40 for six to 14 aspirin per week, and 1.57 for more than 14 per week. The implication, the researchers said, is that "use of aspirin at the highest-dose category … would prevent one to two cases of colorectal cancer" at a cost of eight excess episodes of major gastrointestinal bleeding for every 10,000 person-years. "We're going to need additional studies that clarify the risks and benefits" of aspirin use before making firm recommendations, Dr. Chan said. "For now, individuals need to discuss the options with their physicians." Primary source: Journal of the American Medical AssociationSource reference: Chan AT et al. Long-term Use of Aspirin and Nonsteroidal Anti-inflammatory Drugs and Risk of Colorectal Cancer. JAMA. 2005; 294:914-923.www.CurrencyTrade.FXTrainer.bizwww.EndOfMortgage.com