There are a lot of rumors and myths about cancer that make it hard for people to know what's true about this disease. Here we address some of the common questions people ask about cancer. If you have questions that aren't answered here, be sure to talk with your cancer care team.
How common is cancer?
About half of all men and one-third of all women in the United States will develop cancer during their lifetime.
Cancer is a genetic disease, meaning cancer is caused by certain changes to genes that control the way cells function, especially how they grow and divide. Genetic changes that promote cancer can be inherited from our parents, or they can occur during a person's lifetime—often from exposure to certain substances.
In the latter case, the risk of developing many types of cancer can be reduced by changes in a person's lifestyle, for instance, by staying away from tobacco, limiting time in the sun, being physically active and eating healthy foods.
There are also screening tests that can be done for some types of cancers so they can be found while they are small and before they have spread. In general, the earlier a cancer is found and treated, the better the chances are for living for many years.
Who gets cancer?
More than 1.5 million new cancer cases are diagnosed each year. Anyone can get cancer at any age, but the risk goes up with age. Nearly 9 out of 10 cancers are diagnosed in people ages 50 and older. Cancer can be found in people of all racial and ethnic groups, but the rate of cancer occurrence (called the incidence rate) varies from group to group.
How many people alive today have ever had cancer?
Today, more than 15 million people alive in the US have had some type of cancer. Some of these people are cancer-free; others still have it.
Years ago, most people who had cancer did not live very long. That's not the case anymore. Every year more and more people survive cancer. This is especially true of children with cancer and those whose cancers were found early, before they spread.
The survival rates are different for people with different types of cancers. Some types of cancer grow very slowly. Some respond to treatment very well. Others grow and spread faster and are harder to treat. If you know someone who has cancer, keep in mind that what happens to them could be very different from what happens to someone else with cancer.
What causes cancer?
Things people do: Some cancers can be caused by things people expose themselves to. For example, tobacco use can cause cancer of the lungs, mouth, throat, bladder, kidneys and many other organs. Of course, not everyone who uses tobacco will get cancer and not everyone who gets lung cancer uses tobacco, but it greatly increases a person's risk. It increases their chance of developing heart and blood vessel disease, too.
Spending a lot of time in the sun without protection can cause skin cancer. Melanoma is a very serious form of skin cancer linked to UV light from the sun and tanning beds.
Genes that run in families: About 5 to 10 percent of all cancers are linked to genes that are inherited from parents.
Bottom line: No one knows the exact cause of most cases of cancer. We know that certain changes in our cells can cause cancer to start, but we don't yet know exactly how it all happens. Scientists are studying this problem and learning more about the many steps it takes for cancers to form and grow.
What are the risk factors for cancer?
A risk factor is anything linked to your chance of getting a disease, such as cancer. Different cancers have different risk factors. For instance, exposing skin to strong sunlight is a risk factor for skin cancer, but it's not linked to colon cancer. Some risk factors can actually cause cancer, while others may simply be more common in people who get cancer. For example, old age by itself doesn't cause cancer, but it is a risk factor.
Still, risk factors don't tell us everything. Having one risk factor, or even many, does not mean that someone will get cancer. Some people with one or more risk factors never develop the disease, while others who do develop cancer have no known risk factors. Even when a person who has a risk factor is diagnosed with cancer, there's no way to prove that the risk factor actually caused the cancer.
There are different kinds of risk factors. Some, like a person's age or race, can't be changed. Others are linked to cancer-causing factors in the environment. Still others are related to personal actions, such as smoking. Some factors influence risk more than others, and a person's risk for cancer can change over time, due to factors such as aging or lifestyle.
Some of the major cancer risk factors that can be controlled include:
- Tobacco use
- Physical activity
- Alcohol use
- Sun exposure
- Environmental exposures, such as radon, lead and asbestos
- Exposure to infections such as hepatitis, HPV and HIV
How is cancer treated?
Surgery, chemotherapy and radiation are the three main types of cancer treatment. A person with cancer may have any or all of these treatments. In choosing a treatment plan, the most important factors are generally the type of cancer and the stage (amount) of the cancer. Other factors to consider include the person's overall health, the likely side effects of the treatment and the probability of curing the cancer, controlling it to extend life or easing symptoms.
How do doctors decide how to treat cancer?
Doctors consider each patient as an individual with personal preferences, and then make recommendations based on things like their own personal experience, current research, the goal of treatment (cure or control) and current cancer treatment guidelines.
Can cancer be cured?
Many cancers can be cured, but not all of them and not always. Cure means that treatment has made the cancer go away, and there's no chance that it will come back. It's rare that a doctor can be sure that cancer will never come back. In most cases it takes time, but the longer a person is cancer free, the better the chance that the cancer will not come back.
*Article adapted from the American Cancer Society.
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