Having cancer once does not mean you won't ever have it again. Anyone who has had cancer is still at risk for having a new, different kind of cancer someday. This is called a second cancer. Second cancers can occur any time after treatment for the first cancer. And even after it's cured.

A second cancer can start in a new place. For instance, if you had breast cancer, you may have a new lung cancer in the future. A second cancer can also start in the same part of your body. You may have had colon cancer. Then, years later, you have a second type of colon cancer.

Second cancers are not the same as cancer recurrence. A second cancer is a new, different type of cancer. Recurrent cancer is the same cancer coming back after treatment.

It's hard to know exactly what causes second cancers. There are many known risk factors that can increase your cancer risk. So a second cancer can be caused by whatever caused the first cancer. A second cancer can also be caused by the treatment used to treat the first cancer. Here are some of the things linked to second cancers:

Radiation treatment kills cancer cells. But it can also damage nearby normal cells. Over time, this can lead to another cancer. This means radiation to a certain part of the body can raise the risk for a new cancer growing in that same area. It may cause tumors that don't show up for many, many years after treatment.

For instance, radiation to the chest to treat breast cancer can damage lung cells, too. This may lead to lung cancer in the future. If a lot of your bone marrow (the thick liquid inside your bones) is exposed to radiation, it may cause leukemia (a blood cancer). Radiation for prostate cancer may lead to bladder or rectal cancer. For the most part, the more radiation you've had, the higher the risk for a second cancer in the area that was treated.

Certain chemotherapy (chemo) medicines have been linked to a higher risk for second cancer. And some are linked to getting the blood cancer called leukemia later in life. The risk is higher if you had high doses of chemo. Or got it for a long time. Make sure to ask your health care team if the chemo you had can raise your risk for leukemia or any other types of cancer in the future.

Because these medicines are newer, researchers are still learning about their connection to second cancers. Some targeted therapy medicines that treat melanoma may increase a person's risk for squamous cell carcinoma of the skin.

There are many possible causes of cancer. The most important risk factor for most types of cancer is age. This means surviving cancer once means you will grow older and be at a higher cancer risk. Certain lifestyle factors are also linked to some types of cancer. These include:

• Using tobacco and exposure to secondhand smoke.
• Drinking alcohol.
• Eating a poor diet.
• Being at a higher weight.
• Being exposed to a lot to UV rays from the sun.

Other risk factors linked to cancer are:

• Gene changes that are passed down in families.
• Infection with certain viruses, such as human papillomavirus and HIV.
• Jobs with exposure to harmful substances.

People who have had cancer are often at higher risk for other types of cancer. In fact, about 1 out of 6 people with cancer had a different kind of cancer in the past.

The risk of a second cancer is higher if you had cancer treatment as a child or young adult.

Risk varies depending on the type of cancer you had and the types of treatments you had. It also depends on your family's history of cancer and your overall health and lifestyle.

Your health care team can tell you more about your personal risk for certain kinds of second cancers. They can also tell you what you can do to help decrease your risk and what you should watch for.

There's no sure way you can prevent a second cancer. But you can take steps to help lower your risk:

• Eat a variety of healthy foods, including plenty of vegetables, fruits, and whole grains. Limit red and processed meats, as well as sugary drinks.
• Get exercise every day.
• Get to or stay at a weight that's healthy for you. Ask your doctor for help.
• Don't use any form of tobacco. Ask your doctor for help quitting.
• Limit alcohol. For cancer prevention, it's best to avoid alcohol completely.

A key step to lower your risk for a second cancer is getting routine cancer screenings. Screening tests look for cancer when it's small and hasn't spread. They can help find some kinds of cancer before you have symptoms. Most cancer survivors should follow general screening guidelines. Talk with your doctor about the screening schedule that's best for you.

Go to all of your follow-up appointments with your health care team. Your care team will ask you how you're feeling. They'll also ask what, if any, changes or symptoms you have. Get regular cancer screening tests as advised by your doctor.

Also, be sure to tell your care team if you have new symptoms that don't go away, such as:

• Pain.
• Trouble breathing.
• Lumps or swelling.
• Unplanned weight loss.
• Easy or unusual bleeding or bruising.
• Fevers.
• Blood in your urine or stool.
• Abnormal vaginal bleeding or discharge.
• Nausea, vomiting, or diarrhea.
• A cough that doesn't get better.
• Tiredness that doesn't get better with rest.
• Skin changes.
• Sores that don't heal.

Keep in mind that these symptoms may be, and are most likely, caused by other things. You may have an infection or other problems that can be easily treated. Still, only your doctor can tell for sure that these changes aren't caused by a second cancer.

Talk with your health care team about what kinds of second cancer you may be at risk for. They can help you understand what to watch for and what you can do to help lower your risk. They can also make sure you get the recommended cancer screening tests.

The most important thing about watching for and coping with second cancer is working with your health care team. Your team can give you information and support. They can help you stay healthy.