Thirteen year population based registry study of prostate cancer incidence and trend in Shahroud Iran using Joinpoint regression

Abstract

Prostate cancer ranks second among cancers affecting men and is the fifth leading cause of cancer-related deaths in men worldwide. Currently, there is no updated information about the incidence of prostate cancer in Iran since 2017. This study aims to investigate the incidence rate and secular trend of prostate cancer in Shahroud and Meyami, northeast Iran. Data for this population-based registry study were extracted from the national population-based cancer registration system between 2010 and 2022. Age-standardized incidence rates (ASIR) were calculated using World Health Organization (WHO) reference populations. The annual percent change (APC) was calculated using Joinpoint regression. During 2010 to 2022, an average of 130,641 males comprised the target population. Over this 13-year period, 220 men (aged 43–93 years) were diagnosed with prostate cancer. The ASIR was 14.18 (95% CI: 12.26–16.09) based on the WHO standard population and 11.67 (95% CI: 10.02–13.31) based on the Segi standard population. The secular trend showed no statistically significant change, with an APC of 0.05% (95% CI: -5.43 to 5.89) based on WHO standard and 0.89% (95% CI: -4.98 to 7.26) based on Segi standard. Crude incidence increased from age 40–44 years to 80–84 years, then declined in those aged ≥ 85 years. Age-period-cohort analysis confirmed a log-linear age effect but found no significant net drift or period/cohort effects. In conclusion between 2010 and 2022, prostate cancer incidence in Shahroud and Meyami showed no statistically significant change (ASIR: 14.18/100,000), lower than global estimates. However, this absence of evidence for a trend should not be interpreted as evidence of epidemiological stability given the limited statistical power (220 cases) and the absence of systematic PSA screening in Iran. Alternative explanations including under-detection and registry maturation should be considered. Future studies with larger sample sizes are needed.