No screening test is 100% accurate, but a good screening test is one that results in a decrease in death rates in people with cancer.
Researchers also look for other benefits of screening including improved quality of life or less harmful treatments as a result of finding the cancer early.
The World Health Organization (WHO) suggests reviewing several factors before introducing a test as a screening tool for the general population. These include:
- Sensitivity – How effectively the test identifies people who actually have cancer.
- Specificity – How often a test gives negative (normal) results for people who do not have cancer.
- Acceptability – Will the population who will benefit the most from the test (the target population) agree to be tested by this method.