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News » Filed under: Prevention/Early Detection
senior woman going over colonoscopy results with doctor

Why We Screen for Some Cancers and Not Others

Article date: February 3, 2016

By Stacy Simon

Screening means having a test that looks for cancer or another disease in people who don’t have any symptoms. Some screening tests – such as colonoscopies – can find growths and remove them before they have a chance to turn into cancer. Other screening tests can find cancer early when it’s easier to treat.


The benefits of screening tests – finding cancer early or sometimes even preventing it by removing growths before they have a chance to turn into cancer – must be weighed against any risks of the tests themselves. Risks may include anxiety, pain, or other side effects. And screening isn’t perfect. Sometimes screening misses cancer, and sometimes it finds something suspicious that turns out to be harmless, but must be checked out through additional tests that also carry risks.

This is why the American Cancer Society uses scientific evidence to create guidelines for cancer screening. The guidelines advise people about what screening tests they should get, when they should get them, and how frequently. The higher a person’s risk for cancer – due to age, family history, or other factors – the more likely the benefits of screening will outweigh the risks.

American Cancer Society Screening Guidelines

The Society’s guidelines for average-risk adults recommend regular screening for breast cancer, cervical cancer, and colon cancer, based on scientific evidence that those screenings save lives. Weighing the benefits and risks of screening for prostate cancer and lung cancer is more complicated and must take many factors into consideration. Therefore, the American Cancer Society recommends people become informed and make the decision together with their doctor. For many other cancer types, researchers continue to conduct studies to learn the best ways to find cancer before symptoms appear.

  • Breast Cancer: Women should be able to start screening at age 40 if they want to. All women at average risk of breast cancer should begin yearly screening by age 45. At age 55, women can choose to continue with yearly mammograms, or choose to have them every other year. Women should talk to their doctor about their own personal risk for breast cancer and about any breast changes they notice. Regular mammograms should continue for as long as a woman is in good health.
  • Cervical Cancer: Women between the ages of 21 and 29 should have a Pap test every 3 years. Women between the ages of 30 and 65 should have both a Pap test and an HPV test every 5 years, or a Pap test alone every 3 years. Women over age 65 who have had regular screening tests with normal results should no longer be screened for cervical cancer. Women who are at high risk for cervical cancer may need to be screened more often.
  • Colon Cancer: Most people should begin regular colon screening at age 50, but those with a family history or other risk factors should talk with their doctor about beginning earlier. Several different tests can be used to screen for colon cancer, including colonoscopy, flexible sigmoidoscopy, guaiac-based fecal occult blood test, and more. Discuss which is right for you with your doctor.
  • Lung Cancer: People at high risk for lung cancer should discuss low-dose CT scan with their doctor. “High risk” refers to current smokers (or those who have quit within the past 15 years) 55 to 79 years old who have a smoking history of 30 pack-years or greater. This means smoking an average of 1 pack a day for 30 years, 2 packs a day for 15 years, or the equivalent.
  • Prostate Cancer: Men should discuss the possible risks and benefits of prostate cancer screening with their doctor before deciding whether to be screened. The discussion should take place starting at age 50 for men who are at average risk of prostate cancer and expect to live at least 10 more years. It should take place at age 45 for men who are at higher risk, including African American men and men who have a father or brother diagnosed with prostate cancer, and at age 40 for men at even higher risk. Talk to your doctor about your history.

Reviewed by: Members of the ACS Medical Content Staff

ACS News Center stories are provided as a source of cancer-related news and are not intended to be used as press releases. For reprint requests, please contact permissionrequest@cancer.org.

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