Colorectal cancers begin as precancerous polyps (abnormal growths) in the colon or rectum. They may not cause any symptoms, especially early on. Colorectal cancer screening can find precancerous polyps so they can be removed before they turn into cancer. Screening can also find colorectal cancer early, when treatment works best.
Most people should begin screening for colorectal cancer soon after turning 50, then continue getting screened as recommended by your doctor. You may need to be screened earlier or more often than other people if you are at increased risk of getting colorectal cancer.
Several screening tests can be used to find colorectal cancer. Some are done in a doctor’s office, and some can be done at home. Talk to your doctor about which test is right for you.
The only recommended screening test for lung cancer is low-dose computed tomography.
Lung cancer screening is done yearly on people who—
- Are between 50 and 80 years old, and
- Smoke now or have quit within the past 15 years, and
- Have a history of heavy smoking (20 pack years or more).
A pack year is smoking an average of one pack of cigarettes per day for one year. For example, a person could have a 20 pack-year history by smoking one pack a day for 20 years or two packs a day for 10 years.
If you are thinking about getting screened, talk to your doctor.