Part Three. What works: the evidence for action
Chapter Two. Review of effective interventions
Screening. Spotlight: Costa Rica
Screening is the systematic application of a test to identify individuals at risk of a specific disease. The goal is for people who have not sought medical attention to benefit from further investigation or direct preventive action. Effectively implemented medical screening can prevent disability and death and improve quality of life. Screening tests are available for some chronic diseases, including cardiovascular disease, diabetes, and several site-specific cancers.
The disease or disorder to be considered for screening must be well defined, of public health importance and of known prevalence in the population. An effective, affordable and acceptable treatment must be available to all those who require it. In general, the number of proven screening procedures is limited, although notable exceptions include the following:
- screening for elevated risk of cardiovascular disease using an overall risk approach;
- screening for early detection of breast and cervical cancer, in countries with sufficient resources to provide appropriate treatment.
Spotlight: Cervical cancer screening in Costa Rica
Cervical cancer remains a major health problem, particularly in low and middle income countries. Yet it can be prevented and cured if detected early. Effective screening programmes for cervical cancer in low and middle income countries can help reduce cervical cancer incidence and mortality. For example, in a number of Latin American countries, cervical cytology screening programmes have been in place for more than three decades and show some positive results.
In Costa Rica, cytology screening has been available to women aged 15 years and older since 1970. Some 250 000 smears are carried out every year, and more than 85% of eligible women have been screened at least once. However, nationwide coverage varies greatly and coverage of rural areas is still inadequate. Although the incidence of cervical cancer remained stable from 1983 to 1991, it declined significantly more recently, with a 3.6% decrease in annual incidence in 1993–1997 as compared with 1988–1992.