Defective 3-parameter Gompertz model with frailty term for estimating cure fraction in survival data.

In several survival data, a proportion of units is not susceptible to the event of interest, even if, accompanied by a sufficiently large time, which is so-called immune or cured. In this paper, the defective Gamma 3-parameter Gompertz model with a frailty term is proposed for estimating the cure fraction. This model does not require adding extra parameters for modeling the cure rate, and it accommodates unimodal hazard shapes as well as monotone hazards. A simulation study has been carried out to assess the performance of the maximum likelihood estimators. The model was applied to two real data sets.

Efficacy and safety of fractional CO2 laser and tranexamic acid versus microneedling and tranexamic acid in the treatment of infraorbital hyperpigmentation.

OBJECTIVE: To compare the efficacy and safety of microneedling and fractional CO2 laser in combination with tranexamic acid (TA) in the treatment of infra-orbital hyperpigmentation. PATIENTS AND METHODS: This split-face clinical trial performed on 30 volunteers. The patients were randomly assigned to treat with fractional CO2 laser and microneedling, both combined with TA topically. Three monthly treatment sessions were performed. Two blinded dermatologists evaluated the response after each treatment session and one and three months after the last session. We also asked patients to evaluate their overall satisfaction at the final follow up. Adverse effects have also been documented. RESULTS: Both methods showed significant improvement in all sessions comparing with the baseline state (p value <.05). There were no significant differences between two methods on the days 30, 90, and 150. But the laser showed significantly higher improvement on day 60. The patients' satisfaction did not reveal any significant difference between the two sides. Adverse events were temporary with no significant difference between both sides except for erythema that lasts longer with microneedling. CONCLUSIONS: Both fractional CO2 laser and microneedling in combination with topical TA seem to be effective modalities in the treatment of infraorbital hyperpigmentation with no significant side effects.

Evaluation of the Factors Affecting the Cure Rate of Cervical Intra-Epithelial Neoplasia Recurrence Using Defective Models.

BACKGROUND: Treatment of cervical intraepithelial neoplasia is very important since if it remains untreated, it may progress to cervical cancer. It is usually treated with excisional surgery. This study aimed to find the factors affecting the cure rate of cervical intraepithelial neoplasia recurrence after surgery using defective models. STUDY DESIGN: A retrospective cohort study. METHODS: Excisional surgery was performed on 307 patients with high-grade cervical intraepithelial neoplasia, from 2009 to 2017. The patients were followed up until recurrence based on histopathology report. Hematologic factors were measured before surgery. The cure rates were estimated using defective models with a Gamma frailty term and the results were compared. RESULTS: Neutrophil-to-lymphocyte ratio (NLR) (P<0.001) and excised mass size (P<0.001) had significant impacts on cure rates, and their cut-off values were 1.9 (P<0.001) and 15 mm2 (P<0.001), respectively. Patients with lower neutrophil-to-lymphocyte ratios and larger excised tissues had higher cure rates. Defective 3-parameter Gompertz distribution with gamma frailty term had the best fit to the data, and its estimated cure rates were 98% among patients with an excised mass size of > 15 mm2 and NLR of <1.9, 84% among patients with an excised mass size of >15 mm2 and NLR of >1.9, 79% among patients with an excised mass size of <15 mm2 and NLR of <1.9, and 30% among patients with an excised mass size of <15 mm2 and NLR of >1.9. CONCLUSION: Cervical intraepithelial neoplasia must be identified and treated before its progress. Excision of more tissues during excisional surgery, especially when the NLR of the patient is high, can help to prevent cervical intraepithelial neoplasia recurrence.

Economic inequality in prevalence of underweight and short stature in children and adolescents: the weight disorders survey of the CASPIAN-IV study.

OBJECTIVE: The aim of this study was to determine the determinants of socio-economic inequality in the prevalence of short stature and underweight in Iranian children and adolescents. METHODS: This cross-sectional nationwide study was conducted on 36,486 participants, aged 6-18 years. This school-based surveillance (CASPIAN- IV) program and its complementary part on weight disorders evaluation was conducted in urban and rural areas of 30 provinces in Iran. In addition to physical examination, a validated questionnaire was completed from students and their parents. Socio-economic status (SES) was determined using principal component analysis, and was classified in quintile scale. Inequality in the prevalence of underweight and short stature was assessed using concentration (C) index and slop index of inequality (SII) by the Oaxaca-Blinder decomposition method. RESULTS: The prevalence (95% CI) of underweight and short stature at national level was 10.89 (10.55, 11.23) and 4.15 (3.94, 4.38), respectively; it had a downtrend from the lowest to highest SES quintile. Furthermore, the value of C for underweight and short stature was negative, i.e. inequality was in favor of high SES groups. Moreover, the prevalence gap of underweight and short stature in the first and fifth quintiles of SES was 6.58% and 5.80%, respectively. The highest proportion of this gap was explained by living area. In the multiple logistic model, odds of underweight and short stature were significantly lower in individuals with higher SES. Compared to boys, odds of underweight were decreased in girls, whereas odds of short stature were increased in them. Odds of underweight and short stature were increased in participants from rural areas than in urban areas. With increasing age, the odds of underweight and short stature decreased significantly. CONCLUSION: The results of this study showed that inequality in the prevalence of short stature and underweight was in favor of high SES groups. Moreover, living area was one of the most important determinants that explained this inequality. Therefore, this issue needs to be considered in health promotion policies.

The Effect of Propofol Anesthesia on the Pain Severity and Frequency of Migraine Attacks in Patients with Chronic Migraine Headache over a Six Month Follow Up: An Observational Study.

Propofol is a short-acting intravenous anesthetic that is commonly used for induction and maintenance of anesthesia. Subanesthetic low doses of propofol has also been used to treat intractable migraine attacks in emergency wards with dramatic results. However, there is little information on the long-term efficacy of this drug in migraine headaches. The aim of this nonrandomized prospective observational study was to assess the effect of propofol anesthesia on the pain severity and frequency of migraine attacks in a 6-month follow-up period after anesthesia in patients with migraine headaches. The study was conducted on 51 known cases of migraine ranging in age from 21 to 66 years. Before anesthesia, patients completed a questionnaire including their characteristics, pain intensity of the headache using a visual analog scale, and a number of headache repetitions per month. All patients received propofol as the main anesthetic agent. At the end of anesthesia, the total amount of propofol usage was recorded. Patients were then followed up by telephone in the first, third, and sixth months after anesthesia, and the severity and frequency of the headache were recorded. Pain intensity or pain frequency significantly improved in 22 patients (43.1%), remained unchanged in 24 (47%), and worsened in 5 cases (9.8%) 6 months after anesthesia compared to before the anesthesia. In conclusion, since about half of the patients had significant improvement in the headache, propofol anesthesia may be considered as an acceptable anesthetic method in patients with migraine.

Economic inequality in prevalence of underweight and short stature in children and adolescents: the weight disorders survey of the CASPIAN-IV study

ABSTRACT Objective: The aim of this study was to determine the determinants of socio-economic inequality in the prevalence of short stature and underweight in Iranian children and adolescents. Subjects and methods: This cross-sectional nationwide study was conducted on 36,486 participants, aged 6-18 years. This school-based surveillance (CASPIAN- IV) program and its complementary part on weight disorders evaluation was conducted in urban and rural areas of 30 provinces in Iran. In addition to physical examination, a validated questionnaire was completed from students and their parents. Socio-economic status (SES) was determined using principal component analysis, and was classified in quintile scale. Inequality in the prevalence of underweight and short stature was assessed using concentration (C) index and slop index of inequality (SII) by the Oaxaca-Blinder decomposition method. Results: The prevalence (95% CI) of underweight and short stature at national level was 10.89 (10.55, 11.23) and 4.15 (3.94, 4.38), respectively; it had a downtrend from the lowest to highest SES quintile. Furthermore, the value of C for underweight and short stature was negative, i.e. inequality was in favor of high SES groups. Moreover, the prevalence gap of underweight and short stature in the first and fifth quintiles of SES was 6.58% and 5.80%, respectively. The highest proportion of this gap was explained by living area. In the multiple logistic model, odds of underweight and short stature were significantly lower in individuals with higher SES. Compared to boys, odds of underweight were decreased in girls, whereas odds of short stature were increased in them. Odds of underweight and short stature were increased in participants from rural areas than in urban areas. With increasing age, the odds of underweight and short stature decreased significantly. Conclusions: The results of this study showed that inequality in the prevalence of short stature and underweight was in favor of high SES groups. Moreover, living area was one of the most important determinants that explained this inequality. Therefore, this issue needs to be considered in health promotion policies.

The role of Human leukocyte antigen class I on patient survival in Gastrointestinal cancers: a systematic review and meta- analysis.

The prognostic role of Human leukocyte antigen class I (HLA- I) in gastrointestinal cancers has been remained controversial. We performed a meta-analysis to determine the role of classical HLA-I in predicting survival of patients. In addition, the relationship between HLA- I and some clinicopathological factors was evaluated. Published studies investigated HLA-I expression effect on gastrointestinal cancers were evaluated to determine association between HLA- I and overall survival (OS) and recurrence-free survival (RFS) in patients. The used effect sizes were hazard ratio (HR) and Odds ratio (OR) with 95% confidence interval (CI). A total of ten studies included 1307 patients were analyzed. The pooled results revealed that HLA- I overexpression was positively related to OS (HR: 0.72; 95% CI: 0.53-0.96) and demonstrated little association for RFS (HR: 0.70; 95% CI: 0.46-1.08). HLA-I overexpression is negative associated with poorer differentiation of tumor (OR: 0.53; 95% CI (0.43-0.81) and also higher stages of cancer (OR: 0.29; 95% CI (0.13-0.64). HLA- I overexpression was related to a better prognosis on OS and probably had little impact on RFS.

Trend of Gastric Cancer after Bayesian Correction of Misclassification Error in Neighboring Provinces of Iran.

BACKGROUND: Some errors may occur in the disease registry system. One of them is misclassification error in cancer registration. It occurs because some of the patients from deprived provinces travel to their adjacent provinces to receive better healthcare without mentioning their permanent residence. The aim of this study was to re-estimate the incidence of gastric cancer using the Bayesian correction for misclassification across Iranian provinces. MATERIALS AND METHODS: Data of gastric cancer incidence were adapted from the Iranian national cancer registration reports from 2004 to 2008. Bayesian analysis was performed to estimate the misclassification rate with a beta prior distribution for misclassification parameter. Parameters of beta distribution were selected according to the expected coverage of new cancer cases in each medical university of the country. RESULTS: There was a remarkable misclassification with reference to the registration of cancer cases across the provinces of the country. The average estimated misclassification rate was between 15% and 68%, and higher rates were estimated for more deprived provinces. CONCLUSION: Misclassification error reduces the accuracy of the registry data, in turn causing underestimation and overestimation in the assessment of the risk of cancer in different areas. In conclusion, correcting the regional misclassification in cancer registry data is essential for discerning high-risk regions and making plans for cancer control and prevention.

Bayesian adjustment for trend of colorectal cancer incidence in misclassified registering across Iranian provinces.

Misclassification error is a common problem of cancer registries in developing countries that leads to biased cancer rates. The purpose of this research is to use Bayesian method for correcting misclassification in registered cancer incidence of eighteen provinces in Iran. Incidence data of patients with colorectal cancer were extracted from Iranian annual of national cancer registration reports from 2005 to 2008. A province with proper medical facilities can always be compared to its neighbors. Almost 28% of the misclassification was estimated between the province of East Azarbaijan and West Azarbaijan, 56% between Fars and Hormozgan, 43% between Isfahan and Charmahal and Bakhtyari, 46% between Isfahan and Lorestan, 58% between Razavi Khorasan and North Khorasan, 50% between Razavi Khorasan and South Khorasan, 74% between Razavi Khorasan and Sistan and Balochestan, 43% between Mazandaran and Golestan, 37% between Tehran and Qazvin, 45% between Tehran and Markazi, 42% between Tehran and Qom, 47% between Tehran and Zanjan. Correcting the regional misclassification and obtaining the correct rates of cancer incidence in different regions is necessary for making cancer control and prevention programs and in healthcare resource allocation.

Socioeconomic inequality in childhood obesity and its determinants: a Blinder-Oaxaca decomposition / Desigualdade socioeconômica na obesidade infantil e seus determinantes: decomposição de Oaxaca-Blinder

Abstract Objective Childhood obesity has become a priority health concern worldwide. Socioeconomic status is one of its main determinants. This study aimed to assess the socioeconomic inequality of obesity in children and adolescents at national and provincial levels in Iran. Methods This multicenter cross-sectional study was conducted in 2011-2012, as part of a national school-based surveillance program performed in 40,000 students, aged 6-18-years, from urban and rural areas of 30 provinces of Iran. Using principle component analysis, the socioeconomic status of participants was categorized to quintiles. Socioeconomic status inequality in excess weight was estimated by calculating the prevalence of excess weight (i.e., overweight, generalized obesity, and abdominal obesity) across the socioeconomic status quintiles, the concentration index, and slope index of inequality. The determinants of this inequality were determined by the Oaxaca Blinder decomposition. Results Overall, 36,529 students completed the study (response rate: 91.32%); 50.79% of whom were boys and 74.23% were urban inhabitants. The mean (standard deviation) age was 12.14 (3.36) years. The prevalence of overweight, generalized obesity, and abdominal obesity was 11.51%, 8.35%, and 17.87%, respectively. The SII for overweight, obesity and abdominal obesity was -0.1, -0.1 and -0.15, respectively. Concentration index for overweight, generalized obesity, and abdominal obesity was positive, which indicate inequality in favor of low socioeconomic status groups. Area of residence, family history of obesity, and age were the most contributing factors to the inequality of obesity prevalence observed between the highest and lowest socioeconomic status groups. Conclusion This study provides considerable information on the high prevalence of excess weight in families with higher socioeconomic status at national and provincial levels. These findings can be used for international comparisons and for healthcare policies, improving their programming by considering differences at provincial levels.

Resumo Objetivo A obesidade infantil se tornou uma preocupação de saúde prioritária em todo o mundo. A situação socioeconômica (SSE) é um de seus principais determinantes. Este estudo tem como objetivo avaliar a desigualdade socioeconômica com relação à obesidade entre crianças e adolescentes em nível nacional e subnacional no Irã. Métodos Este estudo transversal multicêntrico foi conduzido em 2011-2012 como parte de um programa nacional de vigilância escolar realizado com 40000 alunos, com idade entre 6-18 anos, de áreas urbanas e rurais de 30 províncias do Irã. Utilizando a análise de componentes principais, a SSE dos participantes foi categorizada em quintis. A desigualdade da SSE no excesso de peso foi estimada pelo cálculo da prevalência de excesso de peso (ou seja, sobrepeso, obesidade geral e obesidade abdominal) em todos os quintis da SSE, o índice de concentração (C) e o slope index of inequality (SII). Os determinantes dessa desigualdade foram determinados pela decomposição de Oaxaca-Blinder. Resultados No total, 36529 alunos completaram o estudo (taxa de resposta: 91,32%), dos quais 50,79% eram meninos e 74,23%, habitantes urbanos. A idade média (DP) foi 12,14 (3,36) anos. A prevalência de sobrepeso, obesidade geral e obesidade abdominal foi 11,51%, 8,35% e 17,87%, respectivamente. A SSE com relação a sobrepeso, obesidade e obesidade abdominal foi -0,1, -0,1 e -0,15, respectivamente. O índice C com relação a sobrepeso, obesidade geral e obesidade abdominal foi positivo, o que indica que a desigualdade estava em favor de grupos de baixa SSE. A área de residência, o histórico familiar de obesidade e a idade foram os fatores que mais contribuíram para a desigualdade da prevalência de obesidade observados entre os grupos em SSE mais alta e mais baixa. Conclusão Este estudo fornece informações consideráveis sobre a alta prevalência de excesso de peso em famílias em SSE mais alta em nível nacional e subnacional. Esses achados podem ser usados para comparações internacionais e políticas de saúde, melhorar a programação ao considerar as diferenças em nível subnacional.

Socioeconomic inequality in childhood obesity and its determinants: a Blinder-Oaxaca decomposition.

OBJECTIVE: Childhood obesity has become a priority health concern worldwide. Socioeconomic status is one of its main determinants. This study aimed to assess the socioeconomic inequality of obesity in children and adolescents at national and provincial levels in Iran. METHODS: This multicenter cross-sectional study was conducted in 2011-2012, as part of a national school-based surveillance program performed in 40,000 students, aged 6-18-years, from urban and rural areas of 30 provinces of Iran. Using principle component analysis, the socioeconomic status of participants was categorized to quintiles. Socioeconomic status inequality in excess weight was estimated by calculating the prevalence of excess weight (i.e., overweight, generalized obesity, and abdominal obesity) across the socioeconomic status quintiles, the concentration index, and slope index of inequality. The determinants of this inequality were determined by the Oaxaca Blinder decomposition. RESULTS: Overall, 36,529 students completed the study (response rate: 91.32%); 50.79% of whom were boys and 74.23% were urban inhabitants. The mean (standard deviation) age was 12.14 (3.36) years. The prevalence of overweight, generalized obesity, and abdominal obesity was 11.51%, 8.35%, and 17.87%, respectively. The SII for overweight, obesity and abdominal obesity was -0.1, -0.1 and -0.15, respectively. Concentration index for overweight, generalized obesity, and abdominal obesity was positive, which indicate inequality in favor of low socioeconomic status groups. Area of residence, family history of obesity, and age were the most contributing factors to the inequality of obesity prevalence observed between the highest and lowest socioeconomic status groups. CONCLUSION: This study provides considerable information on the high prevalence of excess weight in families with higher socioeconomic status at national and provincial levels. These findings can be used for international comparisons and for healthcare policies, improving their programming by considering differences at provincial levels.

Trend of hepatocellular carcinoma incidence after Bayesian correction for misclassified data in Iranian provinces.

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.

Bayesian adjustment of gastric cancer mortality rate in the presence of misclassification.

AIM: To correct for misclassification error in registering causes of death in Iran death registry using Bayesian method. METHODS: National death statistic from 2006 to 2010 for gastric cancer which reported annually by the Ministry of Health and Medical Education included in this study. To correct the rate of gastric cancer mortality with reassigning the deaths due to gastric cancer that registered as cancer without detail, a Bayesian method was implemented with Poisson count regression and beta prior for misclassified parameter, assuming 20% misclassification in registering causes of death in Iran. RESULTS: Registered mortality due to gastric cancer from 2006 to 2010 was considered in this study. According to the Bayesian re-estimate, about 3%-7% of deaths due to gastric cancer have registered as cancer without mentioning details. It makes an undercount of gastric cancer mortality in Iranian population. The number and age standardized rate of gastric cancer death is estimated to be 5805 (10.17 per 100000 populations), 5862 (10.51 per 100000 populations), 5731 (10.23 per 100000 populations), 5946 (10.44 per 100000 populations), and 6002 (10.35 per 100000 populations), respectively for years 2006 to 2010. CONCLUSION: There is an undercount in gastric cancer mortality in Iranian registered data that researchers and authorities should notice that in sequential estimations and policy making.

Bayesian adjustment for over-estimation and under-estimation of gastric cancer incidence across Iranian provinces.

AIM: To correct the misclassification in registered gastric cancer incidence across Iranian provinces in cancer registry data. METHODS: Gastric cancer data is extracted from Iranian annual of national cancer registration report 2008. A Bayesian method with beta prior is implemented to estimate the rate of misclassification in registering patient's permanent residence in neighboring province. Each time two neighboring provinces with lower and higher than 100% expected coverage of cancer cases are selected to be entered in the model. The expected coverage of cancerous patient is reported by medical university of each province. It is assumed that some cancer cases from a province with a lower than 100% expected coverage are registered in their neighboring province with more than 100% expected coverage. RESULTS: The condition was true for 21 provinces from a total of 30 provinces of Iran. It was estimated that 43% of gastric cancer cases of North and South Khorasan provinces in north-east of Iran was registered in Razavi Khorasan as the neighboring facilitate province; also 72% misclassification was estimated between Sistan and balochestan province and Razavi Khorasan. The misclassification rate was estimated to be 36% between West Azerbaijan province and East Azerbaijan province, 21% between Ardebil province and East Azerbaijan, 63% between Hormozgan province and Fars province, 8% between Chaharmahal and bakhtyari province and Isfahan province, 8% between Kogiloye and boyerahmad province and Isfahan, 43% Golestan province and Mazandaran province, 54% between Bushehr province and Khozestan province, 26% between Ilam province and Khuzestan province, 32% between Qazvin province and Tehran province (capital of Iran), 43% between Markazi province and Tehran, and 37% between Qom province and Tehran. CONCLUSION: Policy makers should consider the regional misclassification in the time of programming for cancer control, prevention and resource allocation.

Evaluation of prognostic factors effect on survival time in patients with colorectal cancer, based on Weibull Competing-Risks Model.

AIM: The aim of this study was to assess the association between survival of patients with colorectal cancer and prognostic factors in a competing risk parametric model using Weibull distribution. BACKGROUND: The prognosis of colorectal cancer is relatively good in terms of survival time. In many prognostic studies, patients may be exposed to several types of competing events. These different causes of death are called competing risks. METHODS: Data was recorded from 372 patients with colorectal cancer who registered in the Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences (Tehran, Iran) from 2004 to 2015 in a retrospective study. Analysis was performed using competing risks model and Weibull distribution. Software used for data analysis was R, and significance level was regarded as 0.05. RESULTS: The result indicated that, at the end of follow-up, 111 (29.8%) deaths were from colorectal cancer and 14 (3.8%) deaths were due to other diseases. The average body mass index (BMI) was 24.61(SD 3.98). The mean survival time for a patient in 372 was 62.05(SD 48.78) month with median equals to 48 months. According to competing-risks method, only stageIII (HR, 1.69; 95% CI, 1.246-2.315 ), stageIV( HR, 4.51; 95% CI,2.91-6.99 ) and BMI( HR, 0.96; 95% CI, 0.96-0.975) have a significant effect on patient's survival time. CONCLUSION: This study indicated pathologic stage (III,IV) and BMI as the prognosis, using a Weibull model with competing risks analysis, while other models without the competing events lead to significant predictors which may be due to over-estimation.

Bayesian correction model for over-estimation and under-estimation of liver cancer incidence in Iranian neighboring provinces.

AIM: The aim of this study was to obtain more accurate estimates of the liver cancer incidence rate after correcting for misclassification error in cancer registry across Iranian provinces. BACKGROUND: Nowadays having a thorough knowledge of geographic distribution of disease incidence has become essential for identifying the influential factors on cancer incidence. METHODS: Data of liver cancer incidence was extracted from Iranian annual of national cancer registration report 2008. Expected coverage of cancer cases for each province was calculated. Patients of each province that had covered fewer cancer cases than 100% of its expectation, were supposed to be registered at an adjacent province which had observed more cancer cases than 100% of its expected coverage. For estimating the rate of misclassification in registering cancer incidence, a Bayesian method was implemented. Beta distribution was considered for misclassified parameter since its expectation converges to the misclassification rate. Parameters of beta distribution were selected based on the expected coverage of cancer cases in each province. After obtaining the misclassification rate, the incidence rates were re-estimated. RESULTS: There was misclassification error in registering new cancer cases across the provinces of Iran. Provinces with more medical facilities such as Tehran which is the capital of the country, Mazandaran in north of the Iran, East Azerbaijan in north-west, Razavi Khorasan in north-east, Isfahan in central part, and Fars and Khozestan in south of Iran had significantly higher rates of liver cancer than their neighboring provinces. On the other hand, their neighboring provinces with low medical facilities such as Ardebil, West Azerbaijan, Golestan, South and north Khorasans, Qazvin, Markazi, Arak, Sistan & balouchestan, Kigilouye & boyerahmad, Bushehr, Ilam and Hormozgan, had observed fewer cancer cases than their expectation. CONCLUSION: Accounting and correcting the regional misclassification are necessary for identifying high risk areas of the country and effective policy making to cope with cancer.

Systematic review of pancreatic cancer epidemiology in Asia-Pacific Region: major patterns in GLOBACON 2012.

Pancreatic cancer is one of the deadliest cancers with short-term survival rates. Trends for pancreatic cancer incidence and mortality varied considerably in the world. To date, the causes of pancreatic cancer are not known sufficiently, although certain risk factors have been identified such as, smoking, obesity, life style, diabetes mellitus, alcohol, dietary factors and chronic pancreatitis. Since there are no current screening recommendations for pancreatic cancer, primary prevention is very important. Therefore, up-to-date statistics on pancreatic cancer occurrence and outcome are essential for the primary prevention of this disease. Due to the lack of information on epidemiology of pancreatic cancer in most Asian countries, and limited of statistics and registration system in this area, we conducted a systematic review study to evaluate the most recent data concerning epidemiology of pancreatic cancer in Asia-Pacific region. In this review we focused on collected recent data on incidence, mortality, survival and risk factors of pancreatic cancer in this region. In addition, we reviewed and used the data of GLOBOCAN 2012 in this paper to complete the information as a source of compiling pancreatic cancer incidence and mortality rate.

Years of life lost due to gastric cancer is increased after Bayesian correcting for misclassification in Iranian population.

AIM: To estimate the change in years of life lost (YLL) due to gastric cancer mortality after correcting for misclassification in registering causes of death using the Bayesian method. BACKGROUND: For evaluating the health status of a country and determining priority of risk factors, some epidemiologic indicators are needed. Due to premature death, YLL is one of the most widely used indicators. To have an exact estimate of YLL, an accurate death registry data is needed, but the Iranian death registry is subject to misclassification error. MATERIAL AND METHODS: Gastric cancer mortality data from 2006 to 2010 for Iran were extracted from national death statistics. The rate of misclassification in registered causes of deaths was estimated, using Bayesian method for each year. Then YLL of gastric cancer is estimated for different age-sex categories before and after implementing Bayesian method. RESULTS: Using Bayesian method, the estimated misclassification rate for gastric cancer in cancer without label group were 5%, 3%, 3%, 7% and 7% respectively from 2006 to 2010. Estimated Years of life lost due to gastric cancer before correcting misclassification were respectively 111684.93, 114957.31, 112391.93, 112250.53 and 113300.92 person-years for years 2006 to 2010. After correcting misclassification, the total YLL of gastric cancer increased to 1535.19, 921.11, 908.39, 2566.39 and 2507.00 person-years, respectively from 2006 to 2010. CONCLUSION: If health policy makers ignore the existence of misclassification in registered causes of death, they may underestimate the burden of some causes of death and overestimate some others.