Early diagnosis of cancer focuses on detecting symptomatic patients as early as possible so they have the best chance for successful treatment. When cancer care is delayed or inaccessible there is a lower chance of survival, greater problems associated with treatment and higher costs of care. Early diagnosis improves cancer outcomes by providing care at the earliest possible stage and is therefore an important public health strategy in all settings.
Screening is a different strategy than early diagnosis. It is defined as the presumptive identification of unrecognized disease in an apparently healthy, asymptomatic population by means of tests, examinations or other procedures that can be applied rapidly and easily to the target population. A screening programme must include all the core components in the screening process from inviting the target population to accessing effective treatment for individuals diagnosed with disease.
Compared to early diagnosis, cancer screening is a distinct and more complex public health strategy that mandates additional resources, infrastructure and coordination. WHO recommends that screening programmes only be undertaken when their effectiveness has been demonstrated, when resources are sufficient to cover the target group, when facilities exist to confirm diagnoses and ensure treatment, and when the prevalence of the disease is high enough to justify screening.
WHO supports Member States to developand implement cancer early diagnosis and screening programmes, according to assessed feasibility and cost-effectiveness of screening, and with adequate capacity to avoid delays in diagnosis and treatment. In 2017, WHO launched the“Guideto cancer early diagnosis”, whichaims to help policy-makers and programme managers facilitate timely diagnosis and improve access to cancer treatment for all. By developing effective strategies to identify cancer early, lives can be savedand the personal, societal and economic costs of cancer care are reduced.
