What is cancer screening?
Cancer screening refers to tests that can be done to look for signs of cancer or to see if you are likely to develop cancer. There are 2 types of cancer screening tests: early detection tests and preventive screening tests.
- Early detection tests look for cancer that already exists, trying to find it early. Mammograms are an example of an early detection test because they can find breast cancer when it is still really small.
- Preventive screening tests look for growths or cells that are likely to become cancer. Pap tests are an example of a preventive screening test. Pap tests can find precancerous cells before they become cancer and when they can still be removed so that the cancer never develops. Another example of a preventive screening test is a colonoscopy, which can find growths in the colon called polyps and remove them before they turn into cancer.
Why is cancer screening important?
Cancer screening saves lives. There have been many advances in cancer treatment over the past few years. Cancer no longer has to be a death sentence. Early treatment often results in a cure. Many people are now living well after a cancer diagnosis, often because their cancer was diagnosed and treated very early. For example, a small breast cancer may be seen on a mammogram up to 2 years before it can be felt with a breast exam. The cancer can then be treated early, increasing the chances for cure.
What are the recommended tests?
Screening tests that have been shown to have benefit are:
- breast mammograms to check for breast cancer in women
- Pap tests for precancer or cancer of the cervix (the cervix is the opening of the uterus)
- fecal occult blood testing for cancerous or precancerous changes in the colon or rectum
- sigmoidoscopy or colonoscopy for prevention or early detection of cancer in the colon or rectum
Healthcare providers may offer a yearly rectal exam and PSA blood test to screen men age 50 to 75 for prostate cancer. Men should discuss the benefits and harms of these tests with their healthcare provider. At this time there is not enough evidence that screening all men is helpful.
Comparing mammograms from year to year can help detect early cancer. Breast cancer screening guidelines released by the US Preventive Services Task Force (USPSTF) in 2009 recommend a mammogram every 2 years for women 50 to 74 years old. This recommendation is for women of average risk. It is controversial and is being reviewed. Depending on your personal and family history your provider may recommend a different screening schedule. Some women with a high risk of breast cancer may need to start screening earlier than age 50. Ask your healthcare provider when you should start having mammograms and how often you should have them.
The recommendations for how often a woman should have a Pap test depend on age and previous test results.
- You should have your first Pap test by age 21. Keep having Pap tests every 2 years until you are 30. If you have an abnormal Pap test, you may need to have the test more often.
- If you are 30 years old or older, you should keep being screened with the Pap test every 2 years. After you have had 3 normal tests, you may need to have a Pap test just every 3 years.
- If you are 65 to 70 years old, you can stop having Pap tests if you have had 3 normal tests within the last 10 years.
Fecal occult blood testing (FOBT or FIT)
At age 50 men and women should start having fecal occult blood testing once a year to screen for colon and rectal cancer. Usually your provider will give you a kit to use at home for this test. You will put a tiny sample of bowel movement from 3 different days on the cards, pads, or wipes included in the kit. Usually you will then take or mail the samples to your provider or the lab. The samples will be tested for blood. If there is blood in the samples, it usually does not mean you have cancer, but it does mean you will need more tests to see what is causing the blood in your bowel movements.
Sigmoidoscopy and colonoscopy
Sigmoidoscopy and colonoscopy are procedures that look for precancerous or cancerous changes in the colon and rectum. A slim, flexible, lighted tube is inserted into the rectum to view the inside of these organs. These tests are usually begun at age 50. Sigmoidoscopy needs to be repeated every 5 years. Colonoscopy needs to be done every 10 years. (It may need to be done more often if any abnormalities are found.) If you have a family history of colon cancer before age 50 or a medical condition that increases your risk of colon cancer, you will need to start your screenings earlier. Discuss this with your healthcare provider.
Sometimes a test called a barium enema may be used instead of a sigmoidoscopy or colonoscopy to look for colon cancer.
Digital rectal exam and PSA test
For the digital rectal exam, the healthcare provider puts a gloved finger in a man's rectum to feel the prostate gland. Prostate cancers feel very hard compared to normal prostate tissue. If your provider feels something abnormal, then you may have other tests to see if there is a tumor and whether it is a type of cancer that will spread.
The PSA (prostate specific antigen) level in the blood usually rises when a man has cancer of the prostate gland. However, it also rises if the prostate is infected or enlarged. Enlarged prostates are common in middle age and later. The test can give misleading results and cause anxiety, expense, and unnecessary medical procedures. For this reason, the PSA test is not recommended as a general screening test. However, because African American men have the highest rate of prostate cancer in the US, the PSA may be used to screen them. Also, men who have a history of prostate cancer in their families may be screened. Research is ongoing to see when and how PSA might be helpful as a screening test for prostate cancer. Whether you should have a PSA test is something you should discuss with your provider.
Are there other screening tests?
If breast cancer occurs often and at younger ages in your family, you may choose to have a BRCA gene test. A changed form of this gene may greatly increase your risk of breast cancer. The BRCA gene test can show if you have inherited this gene. More frequent breast cancer screening may be recommended for women who have this gene. Some women who have BRCA1 or BRCA2 genes choose to have their breasts removed to keep from getting breast cancer.
How can I know when I should have screening tests?
Which tests you have and the timing of these tests depends on your personal and family history. For example, if someone in your family had colon cancer before age 50, you may need to start screening tests for this type of cancer at an earlier age. Be sure your healthcare provider knows your family history. Ask your provider which cancer screening tests you need and how often.
Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.
HIA File canc3511.htm Release 13/2010