Time trend analysis of age, period, and cohort effects on prostate cancer incidence from 1996 to 2020 in Taiwan

Purpose: Previous studies regarding the time trend of prostate cancer incidence are relatively less, therefore, the present study aimed to explore the time trend of prostate cancer incidence from 1996 to 2020 in Taiwan. Materials and methods: This study employed data from the Taiwan Cancer Registry spanning 1996 to 2020, including patients diagnosed with prostate cancer. Jointpoint regression analysis was used to assess annual incidence trends. Furthermore, an age-period-cohort (APC) model was applied to investigate the independent effects of age, calendar period, and birth cohort on incidence rates. Results: The prostate cancer incidence rate among men continued to increase between 1996 and 2011. The trend leveled off thereafter but rebounded after 2017. A shift in prostate cancer staging has been observed since 2018, with a decreasing proportion of stage 2 cases and a concurrent increase in stage 3 cases. The growth rate of prostate cancer incidence among the population under 65 surpassed the older population. The APC models reveal temporal trends in prostate cancer incidence, which can help in identifying whether observed changes are due to shifts in population demographics, healthcare practices, or other risk factors. Conclusion: The APC analysis indicated that the incidence of prostate cancer is related to age, calendar period, and birth cohort. Taking the age, period, and cohort simultaneously into consideration is a more promising approach to realize the time trend of prostate cancer incidence.