Quality Assessment of the National Cancer Registry in Iran: Completeness and Validity

Introduction: Cancer Registry is one of the important components of health information systems in developing countries. Continuous monitoring of data quality can have a crucial role in controlling cancers. This study aimed to assess the quality of cancer registry data in terms of completeness of coverage and validity. Methods: Data were collected from three main sources, including Pathology registry, Hospital and national death registries in five provinces in Iran during March 2008-March 2011. We used two source capture-recapture method for estimate of cancer registry coverage and measures of validity were percentage of death certificate only (DCO%), histological verified cases (MV%); cancer incidence in childhood based on sex and age group, percentage of cancer in the elderly (80 years or above) and mortality-to-incidence ratio (M:I).We compared them to international standards. Results: The overall completeness was estimated at 54.2% and 32.4% under reporting for stomach cancer in a period of three years (2008 - 2010). MV% and percentage of unknown primary site of the tumor were 68.7%, and 5% respectively. The mortality-to-incidence ratio for men and women was 37.6% and 28.2%, and percentage of cancer in the elderly was 10.9% in 2010 year. The age-specific rate in girls and boys in age groups of 5 - 9 and 10 - 14 years was lower than minimum of the recommended international standards. Conclusions: The results of this study showed data quality of cancer registry is relatively low in terms of the completeness and validity. Cancer registries should pay great attention to the quality of their data. In addition to technical measures in data processing, continuous evaluation of their quality in order to achieve the set goals is essential.