Cancer prevention takes 2 basic forms: early detection and risk reduction. The purpose of early detection is to reduce the mortality associated with a cancer that already exists, but has yet to produce symptoms. This is the primary rationale for most cancer screening tests.
The purpose of risk reduction is to decrease the chances that a cancer will develop in the first place. The more we can learn about what causes cancer, the more likely we are to find ways to prevent it. In the laboratory, scientists explore possible causes of cancer and try to determine exactly what happens in cells when they become cancerous. Researchers also study patterns of cancer in the population to look for risk factors, conditions that increase the chance that cancer might occur and protective factors, which decrease the risk of cancer.
What researchers do know is that cancer develops over time and is often due to a complex mix of factors including lifestyle, genetics, and environment.
Modifiable Risk Factors
To reduce the risk of cancer, concentrate on changing risk factors you can control.
Smoking affects every cell in the body. When a cigarette is inhaled, the smoke and chemicals move into the bloodstream through the lungs. In the bloodstream, these harmful chemicals travel throughout the body. Some may be filtered by the kidneys, which produce urine. Urine is stored in the bladder until it is eliminated from the body. Other substances may be filtered by the liver or eliminated through the colon and rectum. Exposure to these chemicals causes irritation to cells and tissues. Long-term irritation is associated with changes in cells that can eventually lead to cancer.
Smoking and using smokeless tobacco products and regular exposure to environmental tobacco smoke (secondhand smoke) are responsible for nearly one-third of all cancer deaths in the United States each year. Smoking is also associated with approximately 85% of all lung cancer deaths.
People who smoke cigars or pipes have a risk for cancers of the oral cavity that is similar to the risk for people who smoke cigarettes. Cigar smokers also have an increased chance of developing cancers of the lung, larynx, esophagus, and pancreas. The use of smokeless tobacco (chewing tobacco and snuff) causes cancer of the mouth and throat.
There are several tools and options available to help you successfully quit smoking.
While dietary factors clearly have a role to play, the connection between diet and cancer is complex and still not well understood. Some evidence suggests a link between a high-fat diet and colorectal, uterine, and prostate cancers. On the other hand, some studies suggest that foods containing fiber may help protect against colorectal cancer, though this has recently come into question. As a general rule, it is better to eat a well-balanced diet that includes nonsaturated fats, fruits and vegetables, and whole grains.
Obesity has been linked to cancers of the breast (among older women), prostate, pancreas, uterus, colon, and ovary. If you are overweight, talk to your doctor about how to safely lose the excess weight. A dietitian can help with meal planning. Once the weight is lost, it is important to take steps to maintain weight in a healthy range.
In the past, some studies suggested that antioxidant vitamins (C and E) and minerals (selenium) reduce the risk of certain cancers. More recent studies however, have failed to substantiate these findings. Similar conclusions are found with essential vitamins and dietary supplements, such as vitamin D and calcium. Herbs, vitamins, and supplements may interfere with traditional medications. Consult with your doctor before taking any medications. A dietitian can help with suggestions to get essential vitamins and minerals with proper nutrition.
Physical activity improves overall health and well-being. Regular exercise benefits the heart, blood vessels, muscles, bones, and mental health. Research also suggests a link between exercise and a reduced risk of cancer. Recommendations encourage at least 30 minutes of aerobic exercise per day on most days of the week. Aerobic exercise can be as simple as taking a brisk walk every day. Strength training can be done at least 2 days per week. More participation in physical activity increases health benefits.
Talk to your doctor before starting any exercise plan.
Heavy drinkers have an increased risk of cancers of the mouth, throat, esophagus, larynx, stomach, colon and breast, and liver. People who smoke cigarettes and drink heavily have an especially high risk of getting these cancers.
There is some evidence to support moderate drinking to reduce the risk of certain cancers. Moderate alcohol intake is 1-2 drinks per day for men and no more than 1 drink per day for women. It is not necessary to consume alcohol in order to gain health benefits if you choose not to drink.
Radiation is all around us. Over time, exposure can lead to alterations in the cell structure or its DNA. These changes can sometimes lead to cancer.
- Ultraviolet (UV) light from the sun—Causes premature aging of the skin and the 2 most common kinds of skin cancer, squamous cell and basal cell. UV light comes from other sources, like tanning booths and sunlamps. UV radiation has also been linked to melanoma, a skin cancer that can spread throughout the body causing death.
- Ionizing radiation—From x-rays, radioactive substances, or other sources that cause cellular damage and DNA replication. Short- and long-term exposures increase cancer risk. Talk to your doctor or dentist before procedures that may expose you to radiation.
- Radiation therapy for cancer may increase the risk of another cancer developing in the area where the treatment is aimed. Modern radiation therapy equipment is designed to deliver the minimum doses needed while still being effective. If you need radiation therapy, talk to your doctor about the risks and benefits.
Protect yourself from UV light by:
- Wearing protective clothing in the sun.
- Staying in the shade when possible.
- Wearing a wide-brimmed hat to protect your face.
- Using broad spectrum (UVA, UVB) sunscreen with sun protection factor (SPF)-15 or higher.
- Using sunglasses that block UVA and UVB rays.
- Avoiding the sun when it is strongest during the day (10 am-3 pm).
- Avoiding the use of tanning booths or lamps.
Repeated exposure to many chemicals commonly found in the workplace can increase the risk of cancer. Asbestos, nickel, cadmium, uranium, radon, vinyl chloride, benzidine, and benzene are examples of well-known carcinogens in the workplace. For example, inhaling asbestos fibers increases the risk of mesothelioma, a rare type of lung cancer. It is important to follow work and safety rules to avoid or minimize contact with dangerous materials. In general, employers are required to provide employees with information (material safety data sheets, [MSDS]) about dangerous chemicals in the workplace and the ways to protect against exposure.
These chemical may act alone or together with another carcinogen, such as cigarette smoke, to increase the risk of cancer.
Doctors may recommend estrogen alone or in combination with progesterone (hormone replacement therapy) to control menopausal symptoms, such as hot flashes and vaginal dryness. Some studies have shown that the use of estrogen alone increases the risk of cancer of the uterus, which can be avoided by adding progesterone. Using both, though, has been recently shown to increase the risk of breast cancer along with other adverse effects. Because it is no longer clear that the risks of hormone replacement therapy outweigh the benefits, be sure to carefully review your options with your doctor.
- Reviewer: Mohei Abouzied, MD, FACP
- Review Date: 03/2015 -
- Update Date: 05/13/2015 -