Estimation of Completeness of Cancer Registration for Patients Referred to Shiraz Selected Centers through a Two Source Capture Re-capture Method , 2009 Data

BACKGROUND
Cancer has important social consequences with cancer registration as the basis of moving towards prevention. The present study aimed to estimate the completeness of registration of the ten most common cancers in patients referred to selected hospitals in Shiraz, Iran by using capture-recapture method.


MATERIALS AND METHODS
This cross-sectional analytical study was performed in 2014 based on the data of 2009, on a total of 4,388 registered cancer patients. After cleaning data from two sources, using capture-recapture common findings were identified. Then, the percentage of the completeness of cancer registration was estimated using Chapman and Chao methods. Finally, the effects of demographic and treatment variables on the completeness of cancer registration were investigated.


RESULTS
The results showed that the percentages of completeness of cancer registration in the selected hospitals of Shiraz were 58.6% and 58.4%, and influenced by different variables. The age group between 40-49 years old was the highest represented and for the age group under 20 years old was the lowest for cancer registration. Breast cancer had the highest registration level and after that, thyroid and lung cancers, while colorectal cancer had the lowest registration level.


CONCLUSIONS
According to the results, the number of cancers registered was very few and it seems that factors like inadequate knowledge of some doctors, imprecise diagnosis about the types of cancer, incorrectly filled out medical documents, and lack of sufficient accuracy in recording data on the computer cause errors and defects in cancer registration. This suggests a necessity to educate and teach doctors and other medical workers about the methods of documenting information related to cancer and also conduct additional measures to improve the cancer registration system.


Introduction
CCancer, as a chronic disease, is the main health problem in most countries and has important social consequences.It is the second cause of death in developed countries and the third cause of death in less developed and reliability of data and identifying defect areas of them (Ferlay et al., 2005).More structured medical records, stronger cancer registry systems, desirable data agreement, more agreement regarding the cancer stage data elements as well as the type of the received treatment is required in order to assess the process of cancer care quality (Keshtkaran et al., 2013).Complete coverage of the population in cancer registration means to register all the cancer cases in the population of a restricted area such as a province in cancer registration centers (Jensen et al., 1991;Parkin et al., 1994).The ideal percentage of cancer registration should be near 100% (Esteban et al., 1995).There are different methods to measuring the completeness of cancer registration that "capture-recapture method" is one of them.Capture-recapture is a popular method for estimating the completeness of registration in different diseases (Brenner et al., 1995).This method and eventually the virtual three source model should be established as the standard indicator to monitor the quality of case ascertainment of cancer registries.These simple tools can be used to evaluate the level of completeness for case under ascertainment in cancer registries (Suwanrungruang et al., 2011).In two-source capture-recapture method, data are identified and codified for the first source based on some specifications, and then the same procedure will be used for the second source.By estimating the cases that are unique in both sources and the cases that are captured in them, it is possible to estimate the cases that are not mentioned and estimate the actual population by means of various statistical procedures (Poorolajal et al., 2010).In this study, Chapman and Chao methods were used to estimate the completeness of cancer registration in ten most common types of cancer in Iran and around the world in selected health centers of Shiraz, Iran that covers patients of the south of Iran..

Materials and Methods
This study is a cross-sectional analytical study that was performed during the first half of 2014 (based on the data of 2009).The study has covered the available data about cancer in different centers of Shiraz that service high percentage of the patients in southwest of Iran (including the central station of cancer registration, Nemazi Hospital, Dena Hospital, Shafa Hospital, Khalili Hospital, Shahid Faghihi Hospital, MRI Hospital, Kowsar Heart Hospital, Shahid Beheshti Hospital, Ali Asghar Hospital, Amir Oncology Hospital and related pathology centers).Because the data were not codified and registered in the computer and there was not any possibility to restore the data in Shafa and MRI Hospitals, these hospitals were removed from our study.
This study was conducted to estimate the completeness of cancer registration in ten most common cancers around the world (stomach, lung, rectum and colon, breast, skin, Blood & Reticuloendotelial, thyroid, prostate, bladder, and brain and central nervous system) (Bahador A 2008) in selected centers of Shiraz, and also identifying the effect of some variables such as demographic information on the completeness of cancer registration.

The study consists of five steps
Step 1: Information about cancer patients were collected from the central station of cancer registration of Shiraz, then information about all cancer cases under the study were compiled from pathology centers related to each hospital based on their hospital documents and demographic data.Step 2: All the information about the patients of each hospital and pathologic center were entered in Excel software and repeated cases were removed and the exact number of the cases from each source were identified.
Step 3: In this stage, the two sources (eight files related to the hospital and eight files related to their pathologic centers) were combined by using Excel software to identify the number of the cases mentioned in each source and the number of them mentioned in both sources.Required data for creating data link are: fist and last name of the patient, father's name, date of birth, and age that all of them were controlled.
Step 4: In this stage, designing form, Chapman and Chao methods, a confidence interval of 95%, and the statistical formulas were described through Excel.Numerical data from each source and also common data were entered into the software and the percentages of the completeness of cancer registration related to each hospital and each cancer type were specifically estimated and the completeness of all cancer types in all centers was analyzed.
Step 5: The effect of demographic variables on the completeness of the cancer registration was investigated.

Chapman method
L1= number of the cases in the first source L2= number of the cases in the second source d= number of the cases in both sources N was also calculated another time with a confidence interval of 95%: Chao method F1= [L1+L2-2d] and f2=d in Chapman method N was also calculated another time with a confidence interval of 95%:

Results
Totally 4388 cases of cancer in ten cancer types, from eight selected hospitals and eight pathology centers related to them were studied based on the data of 2009.After eliminating repeated cases, the total number of registered cancer reduced to 4031 that 1904 of them were registered in hospitals and 2127 of them in pathology centers and 715 of them were common (Table 1).
Estimating the percentages of the completeness of cancer registration for breast, lung, thyroid, and bladder cancers in the selected centers by Chapman methods were 82%, 70.4%, 66.6% and 66.3%, respectively and by Chao method were 81.7%, 59.9%, 66% and 64.3% respectively, that they showed the highest percentages of the registration.The percentages of the completeness of the cancer registration in blood, prostate, and colorectal cancers by Chapman method were 32%, 37.9% and 38.9% and by Chao method were 31%, 35.3% and 26.5% that they were the lowest.Registration percentages of skin, stomach, and brain cancers by Chapman method were 60.9%, 58.7% and 54.9% and by Chao method were 41.6%, 56.9% and 46.6%.
The results showed that the overall estimation of the completeness of cancer registration in all the selected hospitals of Shiraz by Chapman method was 58.6% and by Chao method was 58.4% (Table 1).
The findings showed that the percentages of the completeness of cancer registration in all the selected hospitals of Shiraz in ages between 40 to 49, 30 to 39, and 50 to 59 by Chapman method were 71.2%, 67.9% and 62.5% respectively and by using Chao method were 71.1%, 67.4% and 62.3% respectively which had the highest percentages in cancer registration there.The lowest percentage was related to the ages under 20 which was 39% by Chapman method and 38.4% by Chao method.The percentages of completeness of cancer registration in ages between 60 to 69, 20 to 29 and above 69 years old were 54%, 52.7% and 51.8% respectively by Chapman method and 53.4%, 51.9% and 51.1% respectively by Chao method (Table 3).
Total percentages of the completeness of cancer registration in the selected hospital of Shiraz for males and females were respectively 41.4% and 67.6% by using Chapman method and 40.9% and 67.5% by using Chao method which shows that the registration of females were higher than males.

Discussion
The results totally showed that between different cancer types under the study, the estimation of the completeness of breast cancer registration in all the selected centers of Shiraz was the highest one and this is similar to some researches like Dortag (2011), Bailly (2008), andBrenner (1994).One reason for this similarity may be the spread of the breast cancer in female group all around the world.Other reasons may be the difference between the survivals of various types of cancer, the special concentration on females' healthcare programs, supporting screening, self-care, and diagnosing and treatment of the disease in early stages, long survival due to adjuvant treatments in compare of other cancer types and older background of developed countries in using data registration and appropriate management in information systems.As the ideal percentage for cancer registration is about 90% to 100% (Esteban et al., 1995;Kroll et al., 2011), the results of the present research show that the registration for breast cancer is not satisfactory.The registration of the breast cancer in this research is higher than the other types of the cancer, but is still needs to be improved.
The results of some studies such as Schmidtmann (Schmidtmann, 2008) and Croccetti (Crocetti et al., 2001) also indicate that the registration in those researches were higher than our research.The reasons may vary from differences between societies and structural and management differences in health and treatment systems of these countries to differences between the attitudes of the health system managers about the importance of the information for making policies and planning for the future to control the disease, prevention and treatment in early stages, and improving the quantity and the quality of the patients' lives.
In contrast, Seddon's (1997) research in England, as a developed country, showed that the completeness of breast cancer registration was 47.5% (Seddon and Williams, 1997) that was lower than our research.This difference may be because of the time of that research (two decades ago), so this comparison seems to be not logical.
Estimations of the completeness of stomach cancer registration in selected centers were 58.7% and 56.9% that put it in the sixth place among the ten cancer types under the study.The results are not similar Dortag's (2011) study. In Jeong-Soo IM's (2000) study in South Korea, the lowest registration rate was for stomach cancer (Jeong-Soo Im et al., 2000) that is similar to the present.Generally the study in South Korea showed registration rates which are very similar to the present study, especially for stomach cancer.Also both studies emphasize on the improvement of cancer registration indices.
The percentages of the completeness of lung cancer registration in all selected centers were 70.4% and 59.9% that put this cancer in the second place.This may be because of the spread of the disease and also the ability to diagnose the disease based on its different risk factors.As already mentioned, the percentage of lung cancer registration in the target population is in an appropriate condition in compare to other cancer types, but it still needs to be improved.Croccetti ( 2001) carried out a research in Tuscany, Italy which the results of that research were more satisfactory (Seddon DJ and Williams EMI, 1997).
Finally it seems that according to the acceptable results in the registration of breast and lung cancers in the selected centers of Shiraz University of Medical Sciences, it is necessary to perform complementary studies for finding the reason of these differences comparing with other cancer types.
The percentages of the completeness of skin cancer registration in the selected centers were 60.9% and 41.6% that put it in the sixth place which is not acceptable.Therefore, it needs to be improved in data registration.It is suggested to compare the results of this study to some countries like Australia that has the highest regional spread of the disease to have a better comparison.
Estimating the completeness of the colorectal cancer in the selected centers were 38.9% and 26.5% which put it in the lowest place and it is similar to Dortag's research (Dortag et al., 2011).Bailly's (2008) research showed that colorectal cancer had higher registration percentage than the present research, but it had lower registration percentage in compare to other cancer types (Brenner et al., 1997) that is similar to the present research.One reason for this may be the different spread of colorectal cancer in developed countries and developing countries like Iran due to the differences in life styles, diets, eating fast foods and drinking alcoholic drinks in that countries.
The estimations of the completeness of Blood & Reticuloendotelial cancer registration in the selected centers were 32.5% and 31% that put it in the ninth place, which is not acceptable.The reasons for this may be the low survival, high fatality, and the short time for diagnosing this disease due to metastatic and end stage.
For thyroid cancer, the percentages of the completeness of the cancer were 66.6% and 66% which put this cancer in the second place.The result for thyroid cancer is similar to Jeong-Soo Im's (Jeong-Soo et al., 2000) research, but the percentage of the present research is lower.According to the registration, this cancer also doesn't have a good condition in the present research.As the diagnosis of thyroid cancer can be based on concise pathologic examinations and also low spread of this disease in Iran (eighth in females and fifteenth in males), it seems that Shiraz University of Medical Sciences can be used as the reference for other provinces.
About prostate cancer, the registration percentages were 37.9% and 35.3% which is in the ninth place and is not acceptable.The results are not similar to Dortag's (Dortag et al., 2011) andMcClish's (McClish andPenberthy, 2004) researches.It is important to know that prostate cancer is in the fourth place (in males) in Iran, therefore, it shows the importance of the registration for the future and planning for prevention programs.The estimations of bladder cancer registration were 66.3% and 64.3% which put it in the fourth place among the cancer types under the study, but it is not satisfactory.The estimations of the completeness of bladder cancer in all the selected centers were 66.3% and 64.3% that put it in the fourth place, which is not again acceptable.The importance of this cancer is more obvious when we notice that it is common in Iranian males (third place among all the cancers) and it is essential to do further studies to find the reason of the incompleteness of the registration related to this cancer to organize and complete the it in future.
For brain and central nervous system the estimations of the completeness were 54.9% and 46.6% that put this cancer in the seventh place, which is low and unacceptable.Considering the spread of this cancer (thirteenth place in men and eleventh place in women) this result is justifiable.
Totally, the estimations of all the cancer types in all the selected centers after combining were 54.9% and 46.6% which are not generally acceptable and they need to be improved through scientific and also practical plans to reach an appropriate place in data registration.The results of the present study were compared to some studies like Kroll (2011), Larsen (2009), Bailly (2008), Schmidtmann (2008), Croccetti (2001), McClish (2005), Song (2012), Razum (2000), Ballivet (2000), Brenner (1994), Seddon (1997), Gholamzadeh (2013), (Suwanrungruang, 2011), andZemestani (2013) and the results of these comparisons showed that the percentages of the completeness of cancer registration in this study are lower than the other studies, But they are identical to Drog's (2011) study and higher than Azevedo-Silva's (Azevedo-Siva et al., 2009) research.Also the results show that in all the selected centers of Shiraz, the age group between 40-49 years old has the highest percentage for cancer registration and the age group less than 20 years old has the lowest one.Considering the consequences of the cancer in young patients, the importance of paying attention to this age group is obvious.Ghojazadeh's (Ghojazadeh et al., 2013) research showed that there were fewer registrations in the age group under 20 year old that is similar to the present research, while in the age group upper than 45 years old the results were not similar to the present study.Maybe the reason is various target populations of these two studies.Zemestani's (2013) reseach in Guilan showed that the highest percentage of the completeness of cancer registration was related the age group between 5 to 14 years old (Zemestani et al., 2013) that is not similar to the present study, but the lowest percentage was related to the age group under 4 years old that is similar to the present study.
Peragallo's (Peragallo et al., 2011), Leong-Soo Im's (Jeong-Soo et al., 2000), Bailly's (Bailly et al., 2011) studies were almost identical to the present study, while Kroll's (Kroll ME et al., 2011) results were not similar to this study.Totally, the comparison between the previous studies and the present study shows that in previous studies in some age groups like young or children patients the percentages of cancer registration were higher than the other age groups which is maybe because of the special concern about the cancer in early ages in developed countries.The existence of specific centers for children's cancer registration in developed countries is the evidence of the special attention to these age groups.The results also show that in all the selected centers, females had higher cancer registrations than males.Regarding this difference, the results of the present study is similar to Bailly's (Bailly DOI:http://dx.doi.org/10.7314/APJCP.2015.16.13.5549 Completeness of Cancer Registration in Shiraz Selected Centers through two Source Capture Re-Capture Method, 2009Data et al., 2011) study in France and McClish's (McClish and Penberthy, 2004) , while it is in contrast with Zemestani's (Zemestani et al., 2013) study, Ghojazadeh's (Ghojazadeh et al., 2013) investigation, Aagahi's (Aghaei et al., 2013) study in Tehran, Croccetti's (Crocetti et al., 2001) study in Tuscany, Italy, and Seddon's (Seddon DJ and Williams EMI., 1997) in England.According to the WHO's (2008) report the patterns of stomach cancer registration are similar in males and females (Boyle and Levin, 2008).
In conclusion, the results totally show that breast cancer had the highest registration in the selected hospitals and colorectal had the lowest registration there.The completeness of cancer registration in all the selected centers was not satisfactory.Patients, who had operation o radiotherapy before, had higher registration.The low percentages in cancer registration show the need of paying more attention to improve the methods and plans of cancer registration from the principals.Appropriate training about documenting data for physicians and other staffs, precise diagnosis about the types of cancer and correctness of medical documents, high accuracy in recording data on the computer, and some other activities for improving the cancer registration system are some important factors to complete the information in health and treatment system.The results of the current study provide useful implications for Health Information managers and cancer registrars.
First, hospital managers and other authorized people should design special and efficient training programs with retraining points in cancer documentation and registration for their staffs and physicians.Second, managers can create opportunities for research on cancer registry and documentation.Third, participating users, managers, external consultants, and all those who are somehow related to Cancer Information Systems or work with them in planning for information systems can be helpful in better cancer registering.
Therefore, it is necessary to strengthen these factors in all organizations, especially hospitals due to the importance of data and information completeness.Investigating different aspects of the completeness of cancer registration in the society based on cancer registration in other geographic situations and regions and comparing the results with the present study is recommended.

Table 3 . Estimation of Completeness of Cancer Registration in Patients Referring to Selected Hospitals and their Related Pathology Centers of Shiraz, 2009 using Capture-recapture Method, Regarding the Age Groups
DOI:http://dx.doi.org/10.7314/APJCP.2015.16.13.5549Completeness of Cancer Registration in Shiraz Selected Centers through two Source Capture Re-Capture Method, 2009 Data