Estimating Completeness of Cancer Registration in Iran with Capture-Recapture Methods.

Completeness is an important indicator of data quality in cancer registry programs. This study aimed to estimate the completeness of registered cases in a population based cancer registry program implemented in five provinces of Iran. Capture-recapture methods were used to esti-mate the number of cases that may have been missed and to estimate rates of completeness for different categories of age, year, and sex. The data used for this study were obtained from three sources: 1) National Pathology Database; 2) National Hospital Discharge Database; and 3) National Death Registry Database. The three sources were linked and duplicates were identified based on first name, last name, father's names, and date of birth, ICD code, and case's residency address using Microsoft Excel. Removing duplicates, the three sources reported a total of 35,643 cases from March 2008 to March 2011. Running many different multivariate models of capture-recapture and controlling for source dependencies revealed an overall under-reporting of 49% in all five registries combined. The estimated completeness differed based on age, sex, and year. The overall completeness was higher for males than females (71.2% for males and 59.9% for females). Younger age had lower rates of completeness compared to older age (38.1% for <40 years, 55.4% for 40-60 years, and 76.7 for>60 years). The results of this study indicated a moderate to severe (depending on the age, sex and year) degree of completeness in the population based cancer registration of Iran.