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Why We Screen for Some Cancers and Not Others

male doctor with female patient during a ct scan

Screening means having a test that looks for cancer or another disease in people who don’t have any symptoms. Some screening tests 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 small, hasn't spread, and might be easier to treat.

The benefits of screening tests should be weighed against any risks of the tests themselves. Risks may include anxiety, pain, bleeding, 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 (called a false-positive), but still needs to be checked out through additional tests that also carry risks and may cause more stress.

This is why the American Cancer Society uses a formal process to review 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 tests should be done. 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 American Cancer Society’s guidelines for average-risk adults recommend regular screening for breast cancer, cervical cancer, and colorectal cancer, based on scientific evidence that shows those screenings may help save lives.

Weighing the benefits and risks of screening for prostate cancer and lung cancer is more complicated because other individual factors are involved. Therefore, we recommend people become informed and talk with their doctor regularly to make the screening decisions that are best for them. 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 have the choice to start yearly screening with a mammogram at age 40 if they wish to do so. All women at average risk of breast cancer should begin yearly screening with a mammogram by age 45. At age 55, women can switch to a mammogram every 2 years, or can continue yearly screening. Women should talk to a health care provider about their own personal risk for breast cancer and about any breast changes they notice. Regular screening should continue for as long as a woman is in good health and expects to live at least 10 more years.
  • 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 (called co-testing) 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. Some women – because of their history – may need to be screened more often. Talk to a health care provider about your history and risk for cervical cancer.
  • Colorectal Cancer: Adults at average risk should begin regular colorectal screening at age 45, but those at high risk for colorectal cancer based on family and/or personal history or other factors may need to: start screening before age 45, be screened more often, or get specific tests. Several different tests can be used to screen for colorectal cancer, including colonoscopy, flexible sigmoidoscopy, guaiac-based fecal occult blood test, and more. Talk with a health care provider about your risk for colorectal cancer and which tests might be good for you, and talk to your insurance provider about your coverage. All abnormal results on non-colonoscopy screening tests should be followed up with a colonoscopy.
  • Lung Cancer: Not all lung cancers can be prevented. Screening is recommended for certain people at higher risk for lung cancer. If you are smoke now or did smoke and quit and you are aged 55 to 74 and in fairly good health, you might benefit from screening for lung cancer with a yearly low-dose CT scan (LDCT). Talk to a health care provider about your risk for lung cancer, how you can quit smoking if you still smoke, the possible benefits, limits, and harms of lung cancer screening, and where you can get screened.
  • Prostate Cancer: The American Cancer Society, along with other leading medical organizations, recommends informed decision-making when it comes to screening for prostate cancer. This means men should discuss the possible risks and benefits of prostate cancer screening with a health care provider before deciding whether to be screened.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.