About-cancer/screening/zh

癌症筛查

在没有症状的人中检查癌症（或可能会变成癌症的异常细胞）称为筛查。

筛查可以帮助医生在引起症状之前及早发现并治疗几种类型的癌症。 早期检测很重要，因为如果尽早发现异常组织或癌症，则可能更容易治疗。 当症状出现时，癌症可能已经开始扩散并且难以治疗。

已经显示了几种筛选测试，可以及早发现癌症并减少死于该癌症的机会。这些测试的筛选试验页上介绍。

But it is important to keep in mind that screening tests can have potential harms as well as benefits.

• Some screening tests may cause bleeding or other health problems.
• Screening tests can have false-positive results—that is, the test indicates that cancer may be present even though it is not. False-positive test results can cause anxiety and are usually followed by additional tests and procedures that also have potential harms.
• Screening tests can have false-negative results—that is, the test indicates that cancer is not present even though it is. False-negative test results may provide false reassurance, leading to delays in diagnosis and possibly causing an individual to put off seeking medical care even if symptoms develop.
• Screening can lead to overdiagnosis—that is, the screening test correctly shows that a person has cancer, but the cancer is slow growing and would not have harmed that person in his or her lifetime. Treatment of such cancers is called overtreatment.

It can be helpful for people to discuss the potential harms as well as benefits of different cancer screening tests with their doctors.