Further Evidence That Aspirin Prevents 25 Percent of All Colon Cancers

New evidence has emerged that adds further insight into the risks and benefits of aspirin for prevention of colorectal cancer. Aspirin has been extensively studied in observational epidemiologic settings that address duration of use, dose, and magnitude of risk reduction. The observational evidence is consistent with evidence from randomized primary prevention trials, which have shown that use of at least 300 mg of aspirin per day for at least 5 years is effective in preventing colon cancer, reducing risk by about 25% (Flossmann and Rothwell 2007). A latency of about 10 years is observed. Like all chemoprevention strategies, risks and benefits must be balanced (Glasziou and Irwig 1995). To date, the risk-benefit considerations of cardiovascular disease, bleeding complications, stomach pain, and heartburn have precluded recommendations for aspirin use as a widespread prevention strategy (Gralow, Ozols et al. 2008; Cuzick, Otto et al. 2009).

In the Lancet, a new study combining data from four randomized trials of aspirin versus control in both primary and secondary prevention of vascular events evaluated risk of colorectal cancer over 20 years (study). A fifth trial compared doses of aspirin. After combining the data on individuals in these five trials the investigators observed that aspirin use reduced the 20-year risk of colon cancer but not rectal cancer. Risk of cancer was reduced by 25% and colon cancer mortality was reduced by 35%. Similar to previous reports, benefit of aspirin use increased with duration of use indicating that aspirin use operates early in the pathway to colon cancer and leading to long-term therapy as the necessary approach for prevention of colon cancer. This study, in contrast with previous evidence suggests that the benefit for colon cancer prevention is obtained with as little as 75 mg per day.

Importantly, this study separately evaluated colon cancer rectal cancers. We have previously shown that the risk factors for these two cancers sites vary substantially (Wei, Giovannucci et al. 2004). The evidence for aspirin adds further support for strategies to be specific to risk, particularly among those who are at increased risk, as is the case for family history.

Related CNiC Posts

Colon Cancer

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Related Links

Your Disease Risk - Colon Cancer Risk Tool

You Cancer Prevent Colon Cancer - Google Knol

Cancer Prevention - Google Knol

Literature Cited
Cuzick, J., F. Otto, et al. (2009). "Aspirin and non-steroidal anti-inflammatory drugs for cancer prevention: an international consensus statement." Lancet Oncol 10(5): 501-507.

Flossmann, E. and P. M. Rothwell (2007). "Effect of aspirin on long-term risk of colorectal cancer: consistent evidence from randomised and observational studies." Lancet 369(9573): 1603-1613.

Glasziou, P. P. and L. M. Irwig (1995). "An evidence based approach to individualising treatment." BMJ 311: 1356-1359.

Gralow, J., R. F. Ozols, et al. (2008). "Clinical cancer advances 2007: major research advances in cancer treatment, prevention, and screening--a report from the American Society of Clinical Oncology." J Clin Oncol 26(2): 313-325.

Wei, E. K., E. Giovannucci, et al. (2004). "Comparison of risk factors for colon and rectal cancer." Int J Cancer 108(3): 433-442.

Have a Family History of Breast Cancer? Keep Up a Healthy Lifestyle

Chalk another one up for the power of prevention.  While it's easy to give in to the "heredity is destiny" mindset when it comes to diseases like breast cancer, new research from the Women's Health Initiative suggests that women can take positive steps to lower their risk of breast cancer even if they have a family history of the disease.

The study, released early in the journal Breast Cancer Research (link) and reported yesterday on futurity.org (link), followed over 85,000 postmenopausal women who were part of the federal Women's Health Initiative Observational Study.  Researchers classified women by family history - those with a first degree relative (sister, mother) who had breast cancer after the age of 45, and those without - and by health behaviors - those who maintained a healthy weight, exercised regularly, and drank less than one alcoholic drink per day, and those who did not.

What they found after over five years of followup was that a woman's family history had no significant affect on the benefits linked to a healthy lifestyle.  Women with a family history who did all three healthy behaviors (weight, exercise, alcohol) saw drops in their breast cancer risk compared to women with a family history who did none of the healthy behaviors.  The same relationship held for women without a family history.

While the results indicated that a healthy lifestyle didn't lower the risk directly linked to family history, they do show that leading a healthy lifestyle should be an important goal for all women, including those with a family history of the disease.

Breast health tips for all women include:

• Maintaining a healthy weight throughout life
• Exercising regularly
• Drinking only moderately (less than 1 drink/day), if at all
• Avoiding long-term use of postmenopausal hormones, especially those with estrogen plus progestin
• Getting screened regularly - clinical breast exams in 20's and 30's, with annual mammograms added in 40's.

To get an estimate of your breast cancer risk as well as personalized prevention tips, visit Your Disease Risk.

A Good Snack, Ruined - Movie Theater Popcorn

Fifteen years after its ground-breaking expose’ on the dietary train wreck that is movie theater popcorn, the Center for Science in the Public Interest has published results of a new study showing that little has changed when it comes to the cinema-show favorite “snack” (report). The popcorn choices carried by most major theater chains range from 400 – 1200 calories and are packed with salt and “essentially fried in one to three days’ worth of saturated fat.” Other standard snack choices fair little better, with CSPI concluding that the best movie-time snack choice is no snack at all. No argument here.

The problem with popcorn, though, is in the preparation, not the grain itself. Popcorn is actually a whole grain food – which isn’t widely known – and if it’s popped at home in an air popper or over the stove with a small amount of healthy oil like canola oil, it can be a very healthy and tasty snack. Add just a dash of salt (not too much) and you’ll feel like you’re in a darkened theater waiting for the previews - and without the calories, saturated fat, and sodium of three fast food hamburgers.

Colon Cancer Screening - Just a (great) first step

New research results out today suggest that 1 in 13 colon cancers may be missed on colonoscopy. There are a few reasons this may happen - some you can control and some you can't. Completing the colonoscopy prep is one you can control - having a clean, prepped colon reduces the changes that a tumor is missed during the exam. But the results also highlight that colon cancer screening is just one part of colon cancer prevention.

A study from Wei and colleagues showed that even among those who are compliant with colon cancer screening recommendations, other lifestyle factors (maitaining a healthy body weight, limiting red and processed meat intake, regular physical activity, taking a folate supplement) contributed to a significant risk reduction.


This means even if you get the "all clear" after a colonoscopy, you shouldn't sit back and think you've done all you can. You've taken a great first step, so use that momentum to make other healthy choices too.

Reduce risk of breast cancer through action today

Breast cancer prevention means taking action now. We talked about awareness earlier this week and have discussed drug strategies to reduce risk of breast cancer in high risk or postmenopausal women. But for every woman there are things to do now to lower risk.

1. be active - increase your level of physical activity
2. maintain a healthy weight
3. cut down on the amount of alcohol you drink

Our web tools help you look at your risk compared to other women your age. We also provide some helpful background information. Above all, the message is clear that we can modify risk of breast and other cancers through changing the way we live. Sustained changes can dramatically reduce risk. Weight loss after menopause can halve the risk of breast cancer, for example. It is never too late to increase activity and maintain some weight loss. we describe strategies for increasing physical activity and weight loss in an earlier post.

Do we really need more breast cancer awareness?

The LA Times has a provocative new article out that seems to rail against breast cancer awareness month.

What are the criticisms?
- Since the breast cancer awareness campaign started, age-adjusted rates have remained largely flat.

- Talking about "breast cancer" ignores all of the research done to date that shows there are many different types of breast cancers, with very different etiologies and treatment paths. In particular, screening likely has very different effectiveness for different types of breast cancers.

- Promoting early detction, as the campaign does, leads to unnecessary diagnostic testing and treatment. (it is interesting to note that the major sponsor of breast cancer awareness month is a chemotherapy drug maker)

So is it time for the message to be changed? We addressed this, to some extent, in a previous CNiC post - when we talked about the "campaign" to list your bra color on social networking sites to promote breast cancer awareness.

Instead of focusing on awareness of the second most common cancer among women, why not focus energies to something more specific - like increasing enrollment in research studies and clinical trials, as advocated by Dr. Love, Avon and their Army of Women, which has opportunities for breast cancer survivors, those without cancer but who may have an increased risk, and individuals with no cancer history. OR, by focusing on primary prevention of cancer - not just early detection.

And breast cancer is preventable -- maintaining a healthy weight, participating in regular physical activity, and avoiding excess alcohol intake all reduce risk. Research shows that losing weight reduces the risk of overweight and obese women, so it isn't too late to start.

Survey Finds High Condom Use by Teens. Good News for Infection-Related Cancers?

A new survey conducted by the National Center for Sexual Health Promotion at Indiana University has found that well over half of sexually active teens in the United States regularly use condoms when they have intercourse, a percentage much higher than that for sexually active adults.  The survey, reported in today's New York Times (link) and set to appear in the Journal of Sexual Medicine, could be good news in the battle against cancers linked to sexually transmitted infections, if the trend in safer sexual practices is robust and continues into the future.

Although not well known by most people, infections play an important role in the development of some cancers. Worldwide, approximately 15 percent of all cancers have been linked to infections. In developing countries, this number reaches almost 25 percent.

Certain infections can either directly or indirectly cause changes that can lead to cancer. This can happen because of the chronic inflammation that some infections cause or by an infectious agent (like a virus) changing the behavior of infected cells. Infections that compromise the immune system (like HIV) also increase cancer risk by making the body less able to defend against infections that can cause cancer.

Not surprisingly, infection-associated cancers are not a health burden borne equally by all. The poor living conditions and inadequate health care experienced by many people worldwide increase the likelihood of cancer resulting from chronic infections.There are at least ten infectious agents that are known to increase the risk of cancer (see table), and several of them are quite common. Yet, in most instances, only a small proportion of those infected actually go on to develop cancer because it takes a unique set of factors along with the infection to turn normal cells cancerous.

Still, these infectious agents have a substantial impact on cancer worldwide. Of particular importance are human papillomavirus (HPV), hepatitis B and C viruses, and Helicobacter pylori. HPV is a sexually transmitted virus that is linked to numerous cancers, with cervical cancer being the most important. It’s estimated that almost all cervical cancers are caused by HPV infection. Hepatitis B and C infect the liver and together account for the large majority of liver cancer. Finally, Helicobacter pylori, a bacteria that infects the stomach, has been estimated to cause upwards of 75 percent of all stomach cancers, the second most common cancer worldwide.

The promise of prevention is a bright spot when looking at the reach of infection-associated cancers. To lower their risk, individuals can take concrete steps like avoiding blood exposure (by not sharing needles, for example), practicing safer sex and, for women, getting regular Pap tests (which test for cervical cancer). There is also very strong evidence that vaccinating girls (around age 11 or 12) against HPV can greatly reduce the risk of cervical cancer later in life . Growing use of the hepatitis B vaccine worldwide is expected to result in similar benefits in liver cancer. Advances on vaccines for other agents also offer much hope for prevention.