Should You Be Screened for Cancer? The Benefits and Risks

Should you be tested for cancer? Maybe not, says H. Gilbert Welch, M.D., author of the same titled book. Welch is one of a growing group of health professionals urging individuals to make thoughtful decisions about cancer screenings. He says one way to become sick is to start looking for something to be wrong.

Testing for Cancer
Screening is the process of looking for cancer in people who have no symptoms. Individuals who have symptoms or suspicious screening results may have additional diagnostic screening tests. Mammograms, for example, can be both screening and diagnostic.

Benefits...
Physicians, cancer advocacy groups, and patient survivors repeatedly deliver the message that detecting cancer early through screening tests is critical to saving lives. Many people have benefitted from cancer screening when they find potentially dangerous cancers during the window of opportunity when treatment is most likely to be successful. During a colonoscopy, for example, physicians can remove polyps before they have a chance to become cancerous.

...and Risks
However, Welch says, "...most people who are tested will never get cancer, [so] most people cannot benefit from testing. And others will die from cancer despite our best efforts to find cancers early. In fact, screening tests tend to miss the fastest-growing and most deadly cancers."

Screening tests themselves may actually increase risk or cause harm. Take mammograms. Radiation to the breast is a risk factor for breast cancer, especially in younger women, and it's cumulative over time.

Screening tests miss some cancers (false negatives) and also uncover abnormalities that are actually benign. These false positives can trigger a cascade of additional tests, unnecessary treatment (with accompanying side effects), and immeasurable stress and anxiety. For example, treatment for slow-growing prostate cancer, which might not ever cause symptoms, can have serious side effects, such as impaired sexual performance and trouble controlling urination and bowel movements.

In an article published in Journal of the National Cancer Institute the author wrote, "It seems clear that we have done an inadequate job of educating screening candidates about the harms and benefits of cancer screening, including the extent to which screening can reduce cancer mortality."

Be an informed healthcare consumer. Learn all the facts about cancer screening tests you're considering. Recognize what tests can-and cannot-do, and understand the potential outcomes if you are tested. While cancer screening undoubtedly saves some lives, Welch and his like-minded peers encourage you to make individual screening decisions, in collaboration with your physician, that are right for you based on your age, risk factors, and personal tolerance for uncertainty.

Sources:

Welch, Gilbert H. Should You be tested for cancer? Maybe not and here's why. Berkeley and Los Angeles, California, University of California Press, 2004.

Stefanek, Michael Edward, "Uninformed Compliance or Informed Choice? A Needed Shift in Our Approach to Cancer Screening." Journal of the National Cancer Institute. Web. 21 November 2011. http://elproyectomatriz.files.wordpress.com/2011/12/prev-cancer-screening-consent-2011-2.pdf

American Cancer Society. Testing for Prostate Cancer. Web. 2010.
http://www.cancer.org/acs/groups/content/@nho/documents/document/acspc-024618.pdf

National Cancer Institute. "Genetic Testing for Breast and Ovarian Cancer Risk: It's Your Choice." Web. 20 March 2006. http://www.cancer.gov/cancertopics/genetics/genetic-testing-for-breast-and-ovarian-cancer-risk

How to Interpret Cancer Study Results

Consider these two headlines, which announce the same study results:

New drug cuts cancer risk by 50%

Drug results in 2% drop in cancer risk

In this hypothetical study described by the Annie Appleseed project, 100 women take a new drug for cancer and 100 women take a placebo. After five years, two women in the first group develop cancer and four in the placebo group develop cancer. Which headline is correct?

They both are, but each uses a different statistic to describe the same study results. Headline one describes the relative risk of developing cancer. Headline two describes the absolute risk.

Relative Risk
Relative risk is the measure of risk of a certain event happening in one group (women taking a drug) compared to the risk of the same event happening in another group (women taking a placebo). Researchers often use relative risk when describing cohort studies (studies that follow a group over time) and clinical trials.

A relative risk of one means there is no difference between the two groups. A relative risk of more than one means (in our example) that women who do not take the new drug are at increased risk of developing cancer. Relative risk, however, is not an increase in riskand it does not tell you anything about your actual risk. Absolute risk helps you do this.

Absolute Risk
Absolute risk is a measure of the risk of a certain event happening, such as the number of people who may develop (or die from) a certain type of cancer within a certain time period. It does not compare risks; it just states the probability that something will happen and does not take into consideration your other risk factors, such as family history. Your absolute risk of developing cancer increases with age.

The frequently cited statistic that one in eight women will be diagnosed with breast cancer represents a woman's lifetime risk of developing breast cancer, assuming she lives 80 or 90 years. However, a woman's actual absolute risk of developing breast cancer depends on her age. For example, only one out of every 233 women, or .43%, between the ages 30 and 39 are at risk for developing breast cancer, while one out of 27 (3.7%) of women in their 60s are at risk.

Sources:

National Cancer Institute. "Absolute Risk." Web.
http://www.cancer.gov/dictionary?CdrID=666196

National Cancer Institute. "Relative Risk." Web.
http://www.cancer.gov/dictionary?CdrID=618613

Woloshin, Steven, Schwartz, Lisa M. and Welch, H. Gilbert. "Risk Charts: Putting Cancer in Context." Journal of the National Cancer Institute 94 (11) (2002): 799-804. Web.
http://jnci.oxfordjournals.org/content/94/11/799.full

BreastCancer.org. "Risk of Developing Breast Cancer. Web. 19 October 2011.
http://www.breastcancer.org/symptoms/understand_bc/risk/understanding.jsp

Ryan, Nancy. "Relative Risk Vs. Absolute Risk." Annie Appleseed Project. Web. 
http://annieappleseedproject.org/reriveabri.html

George Mason University. "What is the difference between absolute and relative risk?" Stats.org. Web. http://www.stats.org/in_depth/faq/absolute_v_relative.htm

The Benefits and Risks of Barefoot Running

It's safe to say that resorting to the primitive practices of our prehistoric ancestors is typically viewed as a bad thing. We evolved, discovered, and invented our way into a life in which we are no longer dependent on the hunt to bring us food, nor do we fear being stalked by predators. Suffice it to say, we've progressed in a way that's made life much easier.

Why, then, is the barefoot running movement gaining popularity? Is it simply a fad popularized by a few outspoken naturalists? Or is there science that backs a more natural approach to running?

Championed by Christopher McDougall's national bestseller Born to Run, the barefoot, or minimalist, running movement has been gaining some traction due to recent studies. In a paper published in 2010 in the journal Nature, Daniel E. Lieberman, professor of human evolutionary biology at Harvard University, notes the difference in form between running barefoot and running in conventional sneakers. Leiberman found that minimalist runners tend to avoid landing on their heel, or "heel striking," and instead land on the ball or the middle of the foot. By doing this, Leiberman says barefoot runners "have almost no impact collision."

This "impact collision" can generate real problems for those who strike heavily on their heels. In a study published in the 2009 issue of PM&R, the researchers found that modern running shoes wielded more stress on knee, hip, and ankle joints compared to those who ran barefoot. The study found that the reasoning for these increases have much to do by the high arches and elevated heels associated with your conventional running shoe.

Simply put, running barefoot, or in minimalist shoes, forces you to find a more natural form. By landing on the balls of your feet, our natural shock absorbers are able to displace any stress caused by your foot striking the pavement. Conversely, landing heavily on your heel results in increased stress on your joints. This can be translated in knee, ankle, hip, or even lower back pain.

Before you dive head first into your Paleolithic past, be sure you understand the risks. While there is evidence that barefoot running will strengthen your legs and feet, there have also been findings correlated with an increased risk of calf strain, Achilles tendinitis, plantar pain, and blisters.

When in doubt, consult a podiatrist before making the change and communicate any concerns you may have.

Sources:

Daniel E. Lieberman, Madhusudhan Venkadesan, Adam I. Daoud, William A. Werbel

Biomechanics of Foot Strikes & Applications to Running Barefoot or in Minimal Footwear

http://www.barefootrunning.fas.harvard.edu/

ScienceDaily. Retrieved May 16, 2011, from http://www.sciencedaily.com­ /releases/2010/01/100127134241.htm

ScienceDaily. Retrieved May 16, 2011, from http://www.sciencedaily.com­ /releases/2010/01/100104122310.htm

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Radiation Risks

No cancer treatment is risk free. Radiation, chemotherapy, and surgery all have their downsides. Cancer patients who underwent radiation therapy in the past are finding that sometimes the side effects don't manifest until many years after treatment.

Studies show that radiation for breast cancer and Hodgkin's disease, a cancer of the lymph system, increase a patient's long-term risk of dying from cardiovascular disease. The studies evaluated patients who received radiation before the mid-1980s when doses and delivery were less precise than they are today. For breast cancer survivors, the risk is substantially higher in those treated for cancer in the left breast, which is closer to the heart.

There are several types of cancer radiation therapy. However, they all use high-energy radiation to kill cancer cells. According to the National Cancer Institute, about half of cancer patients receive some type of radiation during treatment.

When planning a patient's radiation treatment, a radiation oncologist uses imaging that shows the exact location of the tumor and the healthy areas around it. He can then determine the exact area to treat, the total radiation dose, how much he should allow for spillover into nearby tissue, and the safest angles for delivering the radiation.

During treatment, radiation rays also harm nearby healthy cells. For women with breast cancer in the left breast, or those with Hodgkin's disease who may receive radiation to the chest, the heart is often very close to the tumor and therefore receives some of the radiation.

Today's radiation therapy is more precise and damages less of the surrounding healthy tissue. It's difficult to know if newer forms of radiation will still increase patients' risk for dying of heart disease because it takes 10 to 20 years for cardiovascular problems to show up. Furthermore, radiation affects patients in different ways.

The risk for women receiving treatment for breast cancer, for example, depends on what part of the heart receives radiation, how the oncologist delivers the radiation, and the woman's specific anatomy. In cases where the risk is high, some women opt to have a mastectomy rather than radiation.

If your oncologist recommends radiation therapy, discuss all the potential risks and benefits of this treatment. If you believe the benefits outweigh the risks, you can take additional steps to safeguard your heart health following treatment: 

Check your blood pressure and cholesterol regularly so you can spot abnormalities early. Don't smoke. Tell your dentist you've received radiation treatment; it may negatively affect some dental procedures.

Sources:
Labbe, Martine, BSc, Arriagada, Rodrigo, MD, PhD, Jougla, Eric, MD, Chavaudra, Jean, PhD, Diallo, Ibrahima, PhD, Rubino, Carole, MD, PhD, and Vathaire, Florent de, PhD. "Long-Term Cardiovascular Mortality After Radiotherapy for Breast Cancer." Journal of the American College of Cardiology 57(4) (2011): 445-452. Web.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T18-51YY92D-B&_user=10&_coverDate=01%2F25%2F2011&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ee38cd5a92daf75a5b6713cf3ef9707d

Nainggolan, Lisa. "Left-Sided Radiation for Breast Cancer Ups Heart Disease Risk." Medscape Medical News. Web. 17 August 2006.
http://www.medscape.com/viewarticle/543050

Pittman, Genevra. "Chest Irradiation May Increase Long-Term Heart Risks." Medscape Medical News. Web. 21 January 2011.
http://www.medscape.com/viewarticle/736242

National Cancer Institute. "Radiation Therapy for Cancer." Web. 30 June 2010.
http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation

Friedlander, Arthur H, Sung, Eric C., and Child, John S. "Radiation-induced heart disease after Hodgkin's disease and breast cancer treatment: Dental implications." Journal of the American Dental Association 134(12) (2003): 1615-1620. Web.
http://jada.ada.org/cgi/content/full/134/12/1615 

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