Correction for under-ascertainment in cancer cases in the very elderly (aged 75+): external reference method

Area of Science:

• Epidemiology
• Cancer Registry Science
• Geriatric Oncology

Background:

• Cancer incidence curves can show under-ascertainment in older populations.
• Accurate cancer data is vital for public health planning and resource allocation.

Purpose of the Study:

• To introduce and evaluate a method for correcting under-ascertainment of cancer cases in the elderly (75+).
• To assess the impact of under-ascertainment on cancer incidence rates in Lithuania.

Main Methods:

• Developed a correction method using age-specific rates and coefficients from an external, high-validity registry (Finnish Cancer Registry).
• Applied the method to Lithuanian Cancer Registry data (1993-1997) to estimate corrected incidence rates.

Main Results:

• Lithuanian cancer data revealed under-ascertainment in individuals over 75.
• Crude cancer incidence rates were underestimated by approximately 10% in 1995 and projected to be 20% by 2050.
• The degree of underestimation varied by cancer site and sex.

Conclusions:

• Correcting for under-ascertainment increases estimates of cancer cases and incidence rates in the elderly.
• Accurate age-specific rates are essential for future cancer incidence projections, especially with aging populations.
• Failure to correct for under-ascertainment can lead to significant underestimation of cancer burden and inadequate resource allocation.