Today is World Cancer Day. The World Health Organization (WHO) yesterday released a Guide to Cancer Early Diagnosis.
Early diagnosis is defined as the early identification of cancer in patients who have symptoms of the disease.
The focus of cancer early diagnosis is people who have symptoms and signs consistent with cancer.
The objective is to identify the disease at the earliest possible opportunity and link to diagnosis and treatment without delay.
This contrasts with cancer screening that seeks to identify unrecognized (pre-clinical) cancer or pre-cancerous lesions in an apparently healthy target population.
Screening differs from early diagnosis in that an entire target population is evaluated for unrecognized cancer or precancer and the majority of individuals tested will not have the tested disease
Cancer is now responsible for almost 1 in 6 deaths globally.
More than 14 million people develop cancer every year, and this figure is projected to rise to over 21 million by 2030.
Progress on strengthening early cancer diagnosis and providing basic treatment for all can help countries meet national targets tied to the SDGs.
Most people diagnosed with cancer live in low- and middle-income countries, where two thirds of cancer deaths occur.
Less than 30% of low-income countries have generally accessible diagnosis and treatment services, and referral systems for suspected cancer are often unavailable resulting in delayed and fragmented care.
Delays in cancer care are common, resulting in
- lower likelihood of survival,
- greater morbidity from treatment and
- higher costs of care.
Late-stage presentation and inability to access care are particularly common in Low and Middle Income Countries, resulting in avoidable deaths and disability from cancer.
Early diagnosis strategies improve cancer outcomes by
- providing care at the earliest possible stage,
- offering treatment that is more effective, less costly and less complex.
Note: While improving early diagnosis generally improves outcomes, not all cancer types benefit equally. Cancers that are common, that can be diagnosed at early stages from signs and symptoms and for which early treatment is known to improve the outcome are generally those that benefit most from early diagnosis. Examples include breast, cervical, colorectal and oral cancers.
Early diagnosis is an important public health strategy in all settings.
Cancer screening is a distinct and more complex public health strategy that mandates additional resources, infrastructure and coordination compared to early diagnosis.
To strengthen capacity for early diagnosis, a situation analysis should be performed to identify barriers and deficits in services and prioritize interventions.
There are three steps to early diagnosis that must be achieved in a time-sensitive manner and coordinated:
- awareness and accessing care;
- clinical evaluation, diagnosis and staging; and
- access to treatment.
Step 1: Awareness and accessing care
The first step, “awareness and accessing care” consists of two key components:
(i) symptom appraisal (period from detecting a bodily change to perceiving a reason to discuss the symptoms with a health-care practitioner); and
(ii) health-seeking behaviour (period from perceiving a need to discuss the symptoms with a health-care practitioner to reaching the health facility for an assessment).
Step 2: Clinical evaluation, diagnosis and staging (aka diagnostic interval)
This step has three components:
- accurate clinical diagnosis;
- diagnostic testing and staging; and
- referral for treatment
Step 3: Access to treatment
In the third step, “access to treatment”, the patient with cancer needs to be able to access high-quality, affordable treatment in a timely manner.
Delays and Barriers
Financial, geographic, logistical and sociocultural barriers must be considered and addressed as per national context to improve access to timely cancer treatment.
Building capacity in diagnostic assessment, pathology and tests as well as improving referral mechanisms and establishing care pathways between facilities can overcome common barriers to timely diagnosis.
Interventions to strengthen early diagnosis
A coordinated approach to building early diagnosis capacity should include empowerment and engagement linked to integrated, people-centred services at all levels of care.
A robust monitoring and evaluation system is critical to identify gaps in early diagnosis, assess programme performance and improve cancer services
Link to the WHO news release:
Link to the WHO Guide (English) [PDF]: