Estimation of Thyroid Cancer Incidence in Kerman Province, Iran Via Three Source Capture-recapture Method During Years 2008-2015

Background: This study aimed to estimate the incidence of thyroid cancer and completeness of thyroid cancer case registration in Kerman province, Iran using three source capture-recapture approach during years 2008-2015. Methods: All new cases of thyroid cancers reported during 2008-2015 which were registered by pathology, nuclear medicine and medical records were included in this study. Using the personal identifiers, common cases between sources were linked. The log-linear Poisson regression analysis was applied to estimate the number of unregistered cases. The incidence rate per 100,000 population was calculated. To study the trend, Joint-point regression analysis was performed. Results: Overall, 1153 new cases of thyroid cancer were reported by three sources. Most cases were female (81/7%). The mean age at diagnosis was 41.53±15.69 years. The estimated number of thyroid cancer cases was 1323. The estimated incidence per 100,000 population varied from 4.5 in 2011 to 11 in 2015. The female to male ratio varied from 3.1 in 2015 to 6.7 in 2011. The completeness of registration for all three sources varied from 33.7% in 2008 to 95.1% in 2013. The completeness of medical records, pathology reports, and nuclear medicine reports were 33.1%, 50.7%, and 66.2%, respectively. Conclusion: Despite some improvements in completeness of thyroid cancer registration during the study period, there are still fluctuations within the study period. Furthermore, considering each source separately, the completeness of registration is not satisfactory. Therefore, more effort should be done to increase the completeness of thyroid cancer registration specially through the pathology source.