Cancer Screening

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. Screening tests that look for cancer are called early detection tests. Screening tests that show cancer is likely to develop are called preventive screening.

An example of an early detection test is a mammogram, which can show cancerous breast tumors when they are still tiny. An example of a test that can be used for preventive screening is a Pap test. The Pap test can show cell changes likely to turn into cancer before the actual cancer has developed.

Why is cancer screening important?

Cancer screening saves lives and improves the quality of life for cancer survivors.

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, precancerous changes found with a Pap test can easily be treated and cured before cancer develops. 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, greatly increasing the chances for survival.

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 opening of the uterus)
• fecal occult blood testing (FOBT) for cancerous or precancerous changes in the colon or rectum
• sigmoidoscopy or colonoscopy for colorectal cancer
• digital rectal exams (DRE) for prostate cancer in men.

Mammograms

All women age 40 to 70 years old, who are in good health, should be screened for breast cancer with mammography every 1 to 2 years after counseling by their healthcare provider about the possible risks and benefits of the procedure. Comparing mammograms from year to year can help detect early cancer. If you are over 70, ask your healthcare provider how often you should have a mammogram.

If you have a risk for breast cancer that is much higher than average and you are 25 years old or older, ask your healthcare provider when you should start having mammograms and how often you should have them. If you have a very high risk, you may consider consulting a breast specialist.

Pap tests

Young women should have their first Pap test to screen for cervical cancer when they start having sexual intercourse or become 21. All women should have a Pap test once a year unless, after 3 Pap tests with normal results, their healthcare provider recommends having the test every 3 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 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, you will need more tests. A positive test for blood does not mean you have colon cancer. It means you need to have more tests to see whether you have colon cancer.

Sigmoidoscopy and colonoscopy

Sigmoidoscopy and colonoscopy are procedures for looking for precancerous or cancerous changes in your colon and rectum. A slim, flexible, lighted tube is inserted into your rectum to view the inside of these organs. These tests are usually begun at age 50. Depending on your personal and family history, they may need to be repeated every 5 to 10 years.

If you have a higher than normal risk for colorectal cancer, ask your healthcare provider when and how often you should be tested for colorectal cancer. You may need to start testing before you are 50.

Digital rectal exam

For this test, 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 something abnormal is felt, then you have other tests to see if there is a tumor and whether it is a type of cancer that will spread.

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. This test can show if you have inherited a changed form of the gene that may greatly increase your risk of breast cancer. Some women who have BRCA1 or BRCA2 gene changes choose to have their breasts removed to keep from getting breast cancer.

It is not yet clear if other tests are helpful. One such test is the prostate specific antigen test (PSA). The PSA level in the blood usually rises when a man has cancer of the prostate. However, it also rises if the prostate is infected or enlarged. (Prostate enlargement is common in middle age and later.) The test can give misleading results and cause undue 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, 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.

How can I know when I should have screening tests?

Which tests you have and the timing of these tests depend on your personal and family history. For example, if someone in your family had colon cancer before age 50, you may need to start tests for this type of cancer at an earlier age. Ask your healthcare provider which cancer screening tests you need and how often.