Population-based Incidence and Incidence Trends by Age Group of Female Breast Cancer in Khon Kaen Province, Thailand, 2002-2021

Abstract

This study aimed to delineate the age-specific incidence and temporal trends of female breast cancer in Khon Kaen Province, Thailand, between 2002 and 2021. We conducted a descriptive study using longitudinal data from the Khon Kaen Population-Based Cancer Registry. Incidence was reported using Crude Incidence Rates (CIR) and Age-Standardized Rates (ASR). Temporal trends were evaluated using the Average Annual Percentage Change (AAPC) derived from Joinpoint regression. A total of 5,800 cases were analyzed. The overall incidence showed a consistent upward trend, peaking in 2020 (ASR = 31.38 cases per 100,000 women-years). The overall AAPC was 4.71% for CIR (95% CI 4.0, 5.4, p < 0.001) and 3.57% for ASR (95% CI 3.2, 4.0, p < 0.001). Age-stratified analysis revealed a rising incidence across all age groups. When measured by ASR, the < 40 years age group experienced the most rapid increase (AAPC = 5.12%). Conversely, when measured by CIR, the 55-69 years age group showed the greatest increase (AAPC = 3.80%), reflecting an increasing proportion of elderly individuals. The rising incidence, coupled with an aging population, necessitates a two-pronged approach to public health policy. These findings support further evaluation of age-appropriate screening, awareness programs, stage distribution, mortality, and cost-effectiveness.