After completing this module, students should be able to:

1. Define what a good cancer screening test is.

Screening is the process of identifying asymptomatic individuals with an elevated risk of cancer such that it warrants further diagnostic testing. Earlier identification of disease typically allows earlier diagnosis and treatment, which in turn may decrease mortality from the disease. A good screening test thus must enable both earlier diagnosis and delay of negative outcomes (morbidity and mortality).

The principles of a good screening test for cancer are [1]:

• The cancer will be a major health problem (serious and common)
• The cancer will be more treatable if detected early
• The test should be acceptable to those eligible
• The test should be inexpensive
• The test should have high sensitivity (the vast majority of subjects with the cancer should test positive)
• The test should have high specificity (the vast majority of subjects without the cancer should test negative)
• Screening will have been shown to reduce mortality in randomized controlled trials

1. ‍Screening for cancer [Internet]. BC Cancer Agency; 1999 Sep [updated 2009 Jul 19; cited 2010 Jul 14]. Available from: http://www.bccancer.bc.ca/HPI/CancerManagementGuidelines/ScreeningforCancer.htm