Observational Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. May 28, 2017; 9(15): 704-710
Published online May 28, 2017. doi: 10.4254/wjh.v9.i15.704
Trend of hepatocellular carcinoma incidence after Bayesian correction for misclassified data in Iranian provinces
Nastaran Hajizadeh, Ahmad Reza Baghestani, Mohamad Amin Pourhoseingholi, Sara Ashtari, Zeinab Fazeli, Mohsen Vahedi, Mohammad Reza Zali
Nastaran Hajizadeh, Sara Ashtari, Mohammad Reza Zali, Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran 1985717413, Iran
Ahmad Reza Baghestani, Department of Biostatistics, Shahid Beheshti University of Medical Sciences, Tehran 1971653313, Iran
Mohamad Amin Pourhoseingholi, Zeinab Fazeli, Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran 1985717413, Iran
Mohsen Vahedi, Department of Biostatistics, University of Social Welfare and Rehabilitation Sciences, Tehran 1985717413, Iran
Author contributions: Pourhoseingholi MA was principal investigator and contributing in writing the manuscript; Hajizadeh N contributed to study conception and data analysis; Baghestani AR and Vahedi M contributed to study conception and design; Zali MR contributed to interpretation the results; Ashtari S and Fazeli Z contributed in writing the manuscript; all authors contributed to editing, reviewing and final approval of the article.
Institutional review board statement: The study was reviewed and approved by research committee of research institute for gastroenterology and liver diseases (Tehran).
Informed consent statement: Hereby it is attested that this manuscript which is submitted for publication in World Journal of Hepatology has been read and approved by all authors, has not been published, totally or partly, in any other journal.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Mohamad Amin Pourhoseingholi, PhD, Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tabnak Avenue, Yaman Street, Tehran 1985717413, Iran. amin_phg@yahoo.com
Telephone: +98-21-22432515 Fax: +98-21-22432517
Received: January 25, 2017
Peer-review started: February 1, 2017
First decision: March 6, 2017
Revised: March 16, 2017
Accepted: April 23, 2017
Article in press: April 24, 2017
Published online: May 28, 2017
Abstract
AIM

To study the trend of hepatocellular carcinoma incidence after correcting the misclassification in registering cancer incidence across Iranian provinces in cancer registry data.

METHODS

Incidence data of hepatocellular carcinoma were extracted from Iranian annual of national cancer registration reports 2004 to 2008. A Bayesian method was implemented to estimate the rate of misclassification in registering cancer incidence in neighboring province. A beta prior is considered for misclassification parameter. Each time two neighboring provinces were selected to be entered in the Bayesian model based on their expected coverage of cancer cases which is reported by medical university of the province. It is assumed that some cancer cases from a province that has an expected coverage of cancer cases lower than 100% are registered in their neighboring facilitate province with more than 100% expected coverage.

RESULTS

There is an increase in the rate of hepatocellular carcinoma in Iran. Among total of 30 provinces of Iran, 21 provinces were selected to be entered to the Bayesian model for correcting the existed misclassification. Provinces with more medical facilities of Iran are Tehran (capital of the country), Razavi Khorasan in north-east of Iran, East Azerbaijan in north-west of the country, Isfahan in central part and near to Tehran, Khozestan and Fars in south and Mazandaran in north of the Iran, had an expected coverage more than their expectation. Those provinces had significantly higher rates of hepatocellular carcinoma than their neighboring provinces. In years 2004 to 2008, it was estimated to be on average 34% misclassification between North Khorasan province and Razavi Khorasan, 43% between South Khorasan province and Razavi Khorasan, 47% between Sistan and balochestan province and Razavi Khorasan, 23% between West Azerbaijan province and East Azerbaijan province, 25% between Ardebil province and East Azerbaijan province, 41% between Hormozgan province and Fars province, 22% betweenChaharmahal and bakhtyari province and Isfahan province, 22% between Kogiloye and boyerahmad province and Isfahan, 22% between Golestan province and Mazandaran province, 43% between Bushehr province and Khozestan province, 41% between Ilam province and Khuzestan province, 42% between Qazvin province and Tehran province, 44% between Markazi province and Tehran, and 30% between Qom province and Tehran.

CONCLUSION

Accounting and correcting the regional misclassification is necessary for identifying high risk areas and planning for reducing the cancer incidence.

Keywords: Trend of hepatocellular carcinoma, Cancer incidence registry, Misclassification, Bayesian correction

Core tip: In many developing countries and even in some developed countries some errors occur in disease registry system. Since registered data is used for planning at the national and sub-national level, correcting the existed errors has a great importance. One of these errors is misclassification in registering cancer incidence. It occurs because some patients from divested provinces prefer to get more qualified diagnostic and treatment services at their adjacent provinces with more medical facilities without mentioning their permanent residence. The aim of this study is to investigate the trend of hepatocellular carcinoma after correcting for misclassification error in Iran’s cancer registry using Bayesian method.