Projected cancer burden attributable to population aging: Insight from a rapidly aging society.

Population aging is an increasing challenge for cancer control in rapidly aging societies, yet remains inadequately quantified. We aim to project and illustrate the cancer burden attributable to aging in Korea by utilizing age-period-cohort (APC) models and population attributable fraction (PAF) concepts. From population-based cancer data, incidence and mortality of cancers primarily affected by aging (stomach, colorectal, liver, gallbladder, pancreatic, lung, non-Hodgkin lymphoma, esophagus, prostate, ovarian, male bladder cancers, and female leukemia) and breast cancer were extracted. Aging-attributable fraction, cases, and deaths were estimated for older ages after projection to 2046 by APC models. Future cancer landscapes were projected to evolve due to population aging. While aging-related lung cancer may remain the highest (from 2017-2021: 94,990 cases, 71,726 deaths, PAF_mortality 78%; to 2042-2046: 220,251 cases, PAF_incidence 78%, 114,476 deaths, PAF_mortality 88%), the current high burden of stomach and liver cancers, likely related to infection, will shift to older age with reduced aging-attributable cases but increased PAF_incidence. Emerging burden will arise from lifestyle-related cancers, including colorectal cancer mortality (mortality-to-incidence ratio [MIR] of age ≥65 0.41 to 0.46) and prostate and breast cancer incidence (for age ≥65: 60,099 to 228,539 cases, PAF_incidence 74% to 86%; and 1316 to 31,874 cases, PAF_incidence 1% to 22%, respectively). Our findings highlight the coexistence of traditional and emerging burdens, which should be key priorities for cancer control programs when societies enter the upcoming super-aged decades. Efforts to mitigate forecasted trends are urgently required, including cancer prevention targeting middle-aged adults and cancer care for frail older patients.