Cancer and aging: Epidemiology and methodological challenges

Area of Science:

• Epidemiology
• Public Health
• Gerontology

Background:

• Denmark's comprehensive health registers facilitate robust cancer epidemiology research.
• Established registers minimize common issues like uncertain study populations and diagnostic inaccuracies.
• Methodological challenges persist, particularly in elderly cancer epidemiology.

Purpose of the Study:

• To highlight persistent methodological challenges in elderly cancer epidemiology.
• To discuss the observed decline or plateau in cancer incidence at advanced ages.
• To explore hypotheses explaining this pattern, including reduced diagnostic intensity versus true biological changes.

Main Methods:

• Utilizing Denmark's unique, population-wide, linkable health registers.
• Analyzing individual-level data with complete follow-up for epidemiological studies.
• Reviewing existing cancer epidemiology data to identify limitations.

Main Results:

• Cancer incidence typically peaks between 75-90 years, then declines or plateaus.
• Current data cannot definitively distinguish between true biological resistance and diagnostic artifacts in the oldest-old.
• Hypotheses include asymptomatic disease, insusceptibility, or reduced diagnostic intensity due to co-morbidities.

Conclusions:

• Further research is needed to clarify the reasons behind the cancer incidence patterns in the oldest-old.
• Addressing diagnostic intensity and co-morbidity effects is crucial for accurate elderly cancer epidemiology.
• Danish health registers offer a valuable resource, but methodological refinements are essential for this demographic.