Some types of cancer can be found before they cause symptoms. Checking for cancer (or for conditions that may lead to cancer) in people who have no symptoms is called screening. Screening can help doctors find and treat some types of cancer early. Generally, cancer treatment is more effective when the disease is found early. However, not all types of cancer have screening tests and some tests are only for people with specific genetic risks.
The following are some of the most common cancers and the screening tests widely used:
A mammogram is the best tool doctors have to find breast cancer early. A mammogram is a picture of the breast made with X-rays. The NCI recommends that women in their forties and older have mammograms every 1 to 2 years. Women who are at higher-than-average risk of breast cancer should talk with their health care provider about whether to have mammograms before age 40 and how often to have them.
The Pap test (sometimes called Pap smear) is used to check cells from the cervix. The doctor scrapes a sample of cells from the cervix. A lab checks the cells for cancer or changes that may lead to cancer (including changes caused by human papillomavirus, the most important risk factor for cancer of the cervix). Women should begin having Pap tests 3 years after they begin having sexual intercourse, or when they reach age 21 (whichever comes first). Most women should have a Pap test at least once every 3 years.
Colon and rectum
A number of screening tests are used to detect polyps (growths), cancer, or other problems in the colon and rectum. People aged 50 and older should be screened. People who have a higher-than-average risk of cancer of the colon or rectum should talk with their doctor about whether to have screening tests before age 50 and how often to have them.
- Fecal occult blood test: Sometimes cancer or polyps bleed. This test can detect tiny amounts of blood in the stool.
- Sigmoidoscopy: The doctor checks inside the rectum and lower part of the colon with a lighted tube called a sigmoidoscope. The doctor can usually remove polyps through the tube.
- Colonoscopy: The doctor examines inside the rectum and entire colon using a long, lighted tube called a colonoscope. The doctor can usually remove polyps through the tube.
- Double-contrast barium enema: This procedure involves several x-rays of the colon and rectum. The patient is given an enema with a barium solution, and air is pumped into the rectum. The barium and air improve the x-ray images of the colon and rectum.
- Digital rectal exam: A rectal exam is often part of a routine physical exam. The health care provider inserts a lubricated, gloved finger into the rectum to feel for abnormal areas. A digital rectal exam allows for examination of only the lowest part of the rectum.
You may have heard about other tests to check for cancer in other parts of the body. At this time, there is not enough research to indicate whether routine screening with these other tests saves lives. Talk to your doctor about screenings for other types of cancer.