Aspirin's anti-cancer effects backed by more research

[David Baxter PhD]

Aspirin's anti-cancer effects backed by more research
CBC News
Mar 20, 2012

Papers published in the Lancet suggest ASA may prevent and treat cancer

Newly published international papers are adding to growing research that Aspirin, commonly used now for people in danger of heart attack and stroke, may also help prevent and treat cancer.

Two papers in the Lancet and one paper in the Lancet Oncology, all published Tuesday, chronicle research suggesting daily use of acetylsalicylic acid (ASA, sold under the brand name Aspirin in Canada and other countries) can reduce the long-term risk of cancer death.

However, researchers from the U.K. and Italy, led by Prof. Peter Rothwell of the University of Oxford and John Radcliffe Hospital in England, stress that the short-term effects of daily use of the non-steroidal anti-inflammatory, as well as how risky or beneficial it may be over time, have yet to be determined.

Currently, in North America, medical practitioners are urged to put anyone who has had a heart attack or stroke on anti-platelet therapy (low-dose ASA, to prevent clots) because it can greatly reduce the risk of deadly recurrence.

The Lancet-published papers break down like this:

• Article 1: The authors studied individual patient data from 51 randomized trials of daily Aspirin versus no Aspirin use to prevent heart attacks. They found Aspirin reduced the risk of a cancer death by 15 per cent compared with control subjects, and this improved to a 37 per cent reduced risk of a cancer death for patients taking the medication five years and longer. The reduction in cancer deaths for those taking Aspirin resulted in a 12 per cent reduction in deaths not related to the cardiovascular system. "In view of the very low rates of vascular events in recent and ongoing trials of Aspirin in primary prevention, prevention of cancer could become the main justification for Aspirin use in this setting," the researcher wrote.
• Article 2: For the study on the effect of Aspirin on how cancer spreads (metastasis), new data was collected on metastases of cancers that were diagnosed during all five large randomized trials of daily Aspirin (75 milligrams or more daily), versus control for the prevention of cardio-related events in the U.K. They found that, with an average followup of 6.5 years, the use of Aspirin reduced the risk of cancer with "distant metastasis" by 36 per cent, cut the risk of colon, lung and prostate cancers by 46 per cent, and reduced the chance of bladder and kidney cancers by 18 per cent. Aspirin reduced the overall risk of fatal cancers in the trial populations by 35 per cent, but not the risk of blood and other fatal cancers. "These findings provide the first proof in humans that Aspirin prevents distant cancer metastasis," the researchers note, adding that metastasis had been prevented in previous studies involving animals.
• Article 3: This paper reviewed the effect of Aspirin on metastatic cancer using a review of observational versus randomized trials. Researchers found observational studies showed a 38 per cent reduced risk of colorectal cancer, compared to 42 per cent in randomized trials. Similar matches in risk were found for esophageal, gastric, biliary and breast cancer, prompting the researchers to say, "Observational studies show that regular use of Aspirin reduces the long-term risk of several cancers and the risk of distant metastasis."

In a commentary linked to the published research, scientists from Brigham and Women's Hospital, Harvard Medical School, in Boston said the studies make "a convincing case" that the cardiovascular-protection and anti-cancer benefits of Aspirin outweigh the harms that may include excess bleeding (hemorrhage), and "moves us another step closer to broadening recommendations for Aspirin use."

However, they warn, "these analyses do not account for less serious adverse effects on quality of life, such as less severe bleeding."

Although the Lancet-published studies received no specific funding, Rothwell has received honoraria for serving on advisory boards, clinical trial committees and giving talks from some pharmaceutical companies with an interest in anti-platelet agents, including Bayer, AstraZeneca, Boehringer Ingelheim, Sanofi-BMS and Servier.

 

[bloodwood]

Every time someone posts about a newer benefit of aspirin I giggle to think of this wonderful gem which originally came from willow tree bark. Aspirin continues to have surprising additional benefits. And then I think of the need for bio-diversity and caring for the environment to sustain future discoveries.

We all grew up with aspirin given by our parents and to think that today we are still discovering what else it can do...

 

[David Baxter PhD]

Aspirin for cancer prevention: promising, but not proven

Aspirin for cancer prevention: promising, but not proven
by Howard LeWine, M.D., Harvard Health Blog
March 22, 2012

Will the increasingly high-tech war against cancer include aspirin—one of the oldest, least expensive medications around? A trio of new studies from the University of Oxford suggests that aspirin is worth testing as a simple way to help prevent cancer. But these are preliminary findings, and you shouldn’t start taking an aspirin a day without having a conversion with your doctor. That’s because aspirin has side effects that could offset any possible cancer-fighting benefit.

First, the latest evidence. The Oxford team, led by Dr. Peter M. Rothwell, combed the medical literature for studies that evaluated the effect of taking aspirin on cancer development. Data from several clinical trials—in which people were randomly assigned to take aspirin or a placebo—showed that the risk of developing or dying from cancer was lower among those taking aspirin. The chances of developing metastatic cancer (cancer which has spread to other parts of the body) were also lower.

The Oxford team also looked at data from studies of people who chose to take daily low-dose aspirin. Again, lower risks of several cancers, including colon, stomach and breast cancers, were seen among the aspirin takers. The papers were published March 21 in The Lancet and The Lancet Oncology.

Aspirin in perspective
Among people who have heart disease or are at high risk for it, taking a daily low-dose aspirin has been proven to help prevent heart attacks and strokes. The use of aspirin by seemingly healthy people to prevent heart attack and stroke is less settled. In that group, aspirin’s possible harmful side effects—mostly stomach upset, gastrointestinal bleeding, and hemorrhagic stroke (bleeding in the brain)—may offset any benefits.

For many years, studies have suggested that aspirin might play a role in cancer prevention. The strongest evidence so far has been aspirin’s potential protection against colon cancer. One study suggested that daily doses of 81 milligrams (a baby aspirin) to 325 milligrams (a standard full-strength tablet) could prevent the recurrence of colon polyps in people who have already had them. Most colon cancers start as polyps.

The University of Oxford team’s analyses support—but don’t prove—this possible role for aspirin. Why do I say “support” instead of “prove”? Because none of the studies from which the data were drawn were designed to test the effect of aspirin on cancer. The clinical trials were all performed to evaluate the effect of aspirin on heart disease—looking for a possible cancer connection came later. The long-term follow-up studies were done for a variety of reasons, none of which were to see if aspirin fights cancer. These design problems make it difficult to determine cause and effect.

The only way to tally up the true balance of benefits and risks of aspirin for cancer prevention is with trials specifically designed to do that. Several are underway or in the planning stages.

The American Cancer Society and other groups haven’t endorsed the routine use of aspirin for colon cancer prevention. The thinking is that the iffy evidence of protection is outweighed by the very real risks of internal bleeding.

Preventing cancer now
For right now, I put aspirin for cancer prevention in the promising but unproven category. Don’t wait for the definitive trials. Here are eight ways you can help prevent cancer right now:

1. Avoid tobacco in all its forms, including exposure to secondhand smoke.

2. Choose a healthy diet. Eat more fruits, vegetables, and whole grain foods.

3. Exercise regularly. Physical activity has been linked to a reduced risk of colon cancer, and may help prevent breast and prostate cancer.

4. Stay lean. Obesity increases the risk of many forms of cancer. Calories count; if you need to slim down, take in fewer calories and burn more with exercise.

5. If you choose to drink, limit yourself to one to two drinks a day. Excess alcohol increases the risk of cancers of the mouth, larynx (voice box), esophagus (food pipe) and liver. It also increases a woman’s risk of breast cancer.

6. Avoid unnecessary exposure to radiation. Get medical imaging studies only when you need them. Check your home for residential radon, which increases the risk of lung cancer. Cover up or use sunscreen when out in the sun.

7. Avoid exposure to industrial and environmental toxins, such as asbestos fibers.

8. Avoid infections that contribute to cancer. Examples include hepatitis viruses, HIV, and the human papillomavirus (HPV). Many are transmitted sexually infections; practicing safe sex helps.