Iranian regional cancer incidence is misclassified in neighborhood’s provinces

Cancer is one of the most important causes of death worldwide. There are 14 million new cases of cancer, which recorded globally each year (1). In Iran, cancer is an important health problem (2) and the gastrointestinal cancers are the most frequent cancers among Iranian males and second among females (3, 4). Cancer registration is an important source for measuring the burden of cancer in a population and these data would be useful for policy makers in order to responsible for the provision of health and oncology services, calculating burden of diseases, medical consultations, etc (5). The World Health Assembly passed a resolution in May 2005, recommending all governments to create and implement cancer control plans (6). Iranian ministry of health commenced a National Cancer Registry in 2004, and its data became available by 2006. On that date, in Iran, cancer services were overwhelmed and most patients, who went to a providing care facility, had advanced diseases, with no specific record of diagnosis. Therefore, a Comprehensive National Cancer Control Program (CNCCP) was designed (7) to assess this objective. However, the history of cancer registry foundation was backed in 1955, when the first activities to organizing cancer reporting were initiated by establishing the Cancer Institute at University of Tehran (8). In cancer registry, the complete coverage of all cases is the key criterion for data quality (9). Completeness is defined as the proportion of incident cancer cases that is registered (10). The completeness level of cancer registration is one of the main parts of quality control in such registration system (11). In the absence of this completeness, there would be an underestimation for incidence (and also burden) of any cancers. One problem regarding cancer registry is the geographical part that cancer cases diagnosed and the real hometown of the corresponding registered patients. A population-based cancer registry is usually easier to achieve in smaller countries, while in a vast geographical territory, such as Iran, with different climate and cultural diversity, there are technical and logistic problems. A study on the accuracy of gastric cancer incidence in Ardabil province indicated that none of the sources of pathology reports, death certificates and medical records individually or collectively fully cover the incidence of gastric cancer (12). Although legislations in place are indeed helpful in establishing pathology-based registries (8), misclassification in reported new cancer cases among provinces is still a potential problem for achieving a full …