trend in thyroid cancer incidence in northern iran: a population-based study (2016–2020)

Background: the incidence of thyroid cancer (tc) is increasing globally. this study examined the incidence of tc in mazandaran province, northern iran, from 2016 to 2020.methods: we conducted a cross-sectional study using data from the mazandaran cancer registry. age-standardized incidence rates (asirs) and the average annual percentage change (aapc) with 95% confidence intervals (ci) were calculated using the joinpoint regression program software, version 4.9.0.0.results: the number of cases rose by 90.9%, increasing from 253 in 2016 to 483 in 2020. the asir increased from 6.43 to 11.14 per 100,000. while the overall trend was not statistically significant (aapc=14.5%, p=0.08), a significant increase was observed in males (aapc=19.8%, p<0.05). the incidence rate in women was approximately five times that of men (15.14 vs 3.06 per 100,000, p<0.001) and was more common in urban areas.. most new cases (over 80%) occurred in the 25–59 age group.conclusion: tc incidence has risen substantially in mazandaran province, particularly among women and urban residents. these findings highlight the need for further investigation into underlying causes and preventive measures.