harms and applications (lesson7)
HEALTH PROMOTION AND PREVENTION
Type of prevention Description Target Examples
Primary Eliminate/reduce risk factors Healthy individuals Childhood vaccination & sunscreen
! Cancer-specific: Tobacco
cessation (lung cancer prevention)
Secondary Early detection, before symptoms Asymptomatic at- Blood pressure monitoring & blood
risk individuals glucose testing
! Cancer-specific: Mammography
(breast cancer)
Tertiary Reduce complications and recurrence after Individuals with HIV treatment & physical therapy
diagnosis. Improve QoL and extend survival. disease ! Cancer-specific: Pain
management during cancer therapy
- Health promotion1
- Disease prevention 2
CANCER BURDEN AND TRENDS
- 2018: Cancer = 2nd leading cause of death globally (1 in 6 deaths)
- 2022: ~20 million new cases, 9.7 million deaths
- EU has disproportionately high burden
- Mortality is decreasing, partly due to screening
• Breast, Colorectal, Cervical Cancer (data from SEER, 1975–2022)
• Most people die from lung cancer, despite it being not the most frequently diagnosed disease.
CANCER SCREENING: PRINCIPLES AND PRACTICE
WHO definition: 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.
Checking for disease in individuals who have no symptoms
- Types:
• Opportunistic – offered during other consultations
• Population-based – systematic invitations
- Goals: (1) Reduce mortality and incidence & (2) improve survival and quality of life.
- Why:
• High disease burden
• Availability of tests and treatment
• Possibility of detection before symptoms appear (pre-clinical stage)
• Improve health outcomes
CANCER SCREENING IN BE
- Colorectal cancer (since 2009-2013)
- Cervical cancer (since 2013)
- Breast cancer (since 2001-2002)
Example: Colorectal cancer screening (Nehterlands)
- Ages 55–75 invited biannually
- Fecal Immunochemical Test (FIT) via mail (purple envelope)
- Positive FIT → Colonoscopy
- Colonoscopy= visual inspection + polyp removal
1
Health promotion= Encouragement of activities that facilitate healthy living and well-being.
2
Disease prevention= Assessment of health risks and development of interventions that halt disease progression.
, If the stool test contains more blood than the cut-off value = positive test.
(A follow-up diagnostic test is needed: colonoscopy).
During a colonoscopy, the inside of the colon is visually inspected, and polyps can be removed.
HARMS OF CANCER SCREENING
Why consider harms? Balance between benefits & harms!
Type of screenings Description Example
Physical Unnecessary procedures, Unnecessary colonoscopy and bowel preparation, small
complications risk of complications
Psychological Anxiety, false reassurance Anxiety/distress due to positive test, altered self-
perception
Economical Cost, capacity waste, Colonoscopy costs, wasted medical capacity,
productivity loss transportation, productivity loss
Practical example: false positive stool test in
colorectal cancer screening.
No findings at colonoscopy: it turns out Marc’s
stool test was false positive.
Alternative example: false negative stool test in
colorectal cancer screening
- Other potential harms and considerations:
• Overdiagnosis: Diagnosing disease that would not neg. affect an individual during their lifetime.
• Equity:
o Access to screening: socioeconomic, geographic, health insurance coverage
o Racial/ethnic disparities in health outcomes
• Health literacy: Not everybody is able to understand the instructions or the information.
Everybody should be able to understand what their risks and the benefits are and then make a
decision for themselves.
• Cultural barriers: In some cultures, the stool test is less accepted.
• Environmental impact: If we conduct all these medical procedures, we also have higher
emissions and a higher carbon footprint. If you can be more clever about who we screen and
how much we screen, we can maybe reduce the environmental impacts of screening a bit.