Cancer is the second leading cause of death in the United States. More than 1 million people in the United States get cancer each year. Nearly half of all men and a little over one-third of all women in the United States will have cancer during their lifetimes. Cancer can happen at any age; but more than 3 out of every 4 cancers occur in people over the age of 55. People of all racial and ethnic groups can get cancer. Today, more than 11 million people are living with cancer or have survived the disease.

What are the risk factors that can lead to cancer?

A risk factor is anything that affects your chance of getting a disease. Some risk factors can be changed (lifestyle choices) and others cannot. Risk factors that can't be changed include your age, sex, and family health history. Lifestyle choices include things you do, such as use tobacco and drink alcohol, what you eat, and sun exposure. Other factors are linked to cancer-causing factors in the environment.

But risk factors don't tell us everything. Having a risk factor, or even several risk factors, does not mean that you will get the disease. And some people who get cancer may not have any known risk factors. Even if a person with cancer has a risk factor, it is often very hard to know what part that risk factor may have contributed to the cancer.

Risk factors that we know about

Different kinds of cancer have different risk factors. Some types of cancer and their risk factors are listed below:

• Cancers of the lung, mouth, pharynx (throat), larynx (voice box), bladder, kidney, cervix, esophagus, and pancreas are linked to the use of tobacco. This includes cigarettes, cigars, chewing tobacco, and snuff. Smoking alone causes about one third of all cancer deaths.

• Skin cancer is related to getting too much UV light from the sun or tanning beds or lamps.

• Breast cancer risk factors include: age; a personal or family history of breast cancer as well as changes in hormone levels throughout life-- such as a woman's age at first menstrual period, her number of pregnancies, and her age at menopause. Other risk factors for breast cancer include being very overweight, not getting enough exercise and drinking alcohol.

• While all men are at risk for prostate cancer, several factors can increase the chances of getting the disease. These include age, race, and diet. The chance of getting prostate cancer goes up with age. Prostate cancer is more common among African American men than among white men. (We do not yet know why this is so.) A high-fat diet may play a part in causing prostate cancer. Also, men with a father or brother who has had prostate cancer are more likely to get prostate cancer.

• Certain cancers are related to viral infections and could be prevented by behavior changes or vaccines. An example of this is HPV (human papilloma virus) and cervical cancer.

Can cancer be inherited?

Though many people believe that cancer runs in families, cancer can't be passed on from parent to child the same way that height and eye color are. While some cancers do have genetic risk factors, most people with cancer have not inherited the disease, nor do they pass it on to their children.

People whose close blood relatives (parents, brothers, or sisters) have certain types of cancer may be at increased risk for those cancers. A person's risk for getting cancer is also strongly linked to age and lifestyle factors mentioned above.

Why me?

The first question that comes up for many people who have been told they have cancer is, "What did I do wrong?" or "Why me?" Because doctors don't know for sure what causes cancer in each case, many people come up with their own ideas about why they have the disease.

Some people believe they are being punished for something they did or failed to do in the past. Most people wonder if they did something to cause the cancer. Some think that if they had done something differently, they could have prevented the disease.

If you are having these feelings, it's important to know that you're not alone. All of these thoughts and beliefs are common among cancer patients. But cancer is not a punishment for things you did or didn't do in the past. Don't blame yourself or look for ways you might somehow have prevented cancer. Cancer is not your fault, and it is almost never possible to find out its exact cause. Focus instead on taking good care of yourself now, both physically and emotionally.

Go back to After Diagnosis: A Guide for Patients and Families

Last Medical Review: 03/19/2008
Last Revised: 05/22/2009