The Medical Minute: Cancer prevention

By John Messmer

People often ask their physicians what they can do to prevent cancers. Various supplements and unorthodox treatments to clean out the system and purge toxins are promoted by convincing arguments as a way to improve health and, by inference, reduce cancer risk. The good news is there are some basic behaviors that have been shown to be effective in reducing cancer risk that people can do now.

Smoking

Smoking increases the chance of multiple cancers: lung, mouth, throat, esophagus, larynx (voicebox), pancreas, kidney, cervix, and bladder. Chewing tobacco and snuff increase the risk of mouth, esophagus and throat cancers. Being around smokers is also a risk due to second hand smoke. Even if you do nothing else, avoid tobacco in all forms and amounts.

Eat the right stuff

Limited alcohol consumption has been associated with reduced risk of heart disease, but excess alcohol is bad for the heart and can increase the risk of mouth, throat, esophagus, kidney, liver and breast cancers. Men should keep alcohol consumption to two drinks per day; women should limit themselves to no more than one per day.

Supplements should be added to a healthy diet rather than taken as a substitute for one. However, there is little data to support the use of supplements in cancer prevention, and several have been shown to have no benefit whatsoever in reducing cancer risk.

Plant-based food, particularly a variety of different color vegetables and fruits each day plus grains and legumes (beans, lentils, and the like), reduces the risk of gastrointestinal cancers. Less fat, particularly animal fat, not only lowers risks of cancer, but in combination with a greater proportion of plant foods, can help keep weight in healthy ranges. Obesity has its own risks of cancer.

Control weight and keep active

Being overweight increases the risks of breast, uterus, colon, prostate, esophagus and stomach cancers. In addition to a good diet, exercise helps keep weight down, but even by itself lowers risk of prostate, breast, colon and uterine cancer. A moderate-intensity workout, such as walking briskly 30 minutes per day five days per week, is a good start. Any activity that requires exertion and raises the heart rate can contribute to overall health and, thus, disease prevention. Examples include dancing, yard work, walking, running, rowing and swimming.

Let the sun shine – but cover up

Most skin cancer is preventable, but it’s common due to exposure to the sun and other sources of ultraviolet light. The highest intensity of sunlight is about 10 a.m. to 4 p.m. from April to October, although the season starts earlier and ends later the farther south a person lives. Staying indoors during peak intensity hours is advisable but not always feasible. When outdoors, take advantage of shady areas. Use sun block with a sun protective factor (spf) of at least 15. Light colored, loose-fitting clothing can provide sun protection during outdoor activity, and a broad-brimmed hat will protect the scalp and ears.

There is no safe or healthy tan. Pre-tanning before extended sun exposure may minimally reduce the risk of sunburn, but it does not reduce the risk of cancer and probably increases it (in addition to prematurely aging and wrinkling the skin). Society must reconsider tanned skin as damaged, not attractive.

Get a shot

Human papilloma virus (HPV) is a sexually transmitted infection that causes cancer of the cervix. A vaccination is available for girls beginning around age 9. The vaccine can significantly reduce cervical cancer risk. It is 100 percent effective at protecting against infection with the two strains of HPV responsible for 70 percent of cervical cancer cases.

Hepatitis B increases liver cancer risk. All children are immunized against hepatitis B as part of the recommended immunization series, but older children and adults at risk also should be vaccinated. Anyone who comes into contact with human blood, such as health care workers, should be immunized.

Be judicious

The more sex partners a person has, the greater his or her risk of cancer through HPV infections, hepatitis B infections, and HIV infection, all of which are associated with increased cancer risk. HIV is associated with an increased risk of lymphoma, Kaposi’s sarcoma, and cancer of the liver, cervix and anus.

Similarly, intravenous drug use raises HIV and hepatitis B risk.

Look for it

Since not all types of cancer are preventable yet, in addition to reducing risk through the tactics noted above, looking for cancer early when it is most curable is the final part of the cancer prevention strategy. Women should have regular cervical cancer screenings, if they still have a cervix, and regular mammograms. Younger men – adolescents through the 30s – should check for testicular lumps. Middle-aged and older men may benefit from prostate cancer screening, although how much benefit is still under debate. Men should discuss this with their doctors for personal recommendations.

Colon cancer screening starting at age 50 for most people is accepted as beneficial. Skin cancer screening may be useful for those who have sun damage already.

See your doctor

Periodic health maintenance visits with a primary care provider can help people stay on track with a personal cancer prevention plan.

The bottom line

Although cancer may not be preventable, people can make a significant dent in their risk through healthy living and periodic check-ups.

To learn more, visit Penn State Hershey Cancer Institute, Penn State Milton S. Hershey Medical Center online.

Dr. John Messmer is associate professor of family and community medicine at Penn State College of Medicine and a staff physician at Penn State Hershey Medical Center.

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Last Updated March 19, 2009