|Year : 2019 | Volume
| Issue : 1 | Page : 16-20
The incidence of testicular cancer in Iran from 1996 to 2017: A systematic review and meta-analysis
Soheil Hassanipour1, Mohammad Ghorbani2, Milad Derakhshan3, Hamed Fouladseresht4, Shokrollah Mohseni5, Elham Abdzadeh6, Shirin Riahi7, Morteza Arab-Zozani8, Hamed Delam4, Hamid Salehiniya9
1 Gastrointestinal and Liver Diseases Research Center, Guilan University of Medical Sciences, Rasht; Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
2 Department of Public Health and School of Health, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran
3 Department of Public Health, Faculty of Health, Baqiyatallah University of Medical Sciences, Tehran, Iran
4 Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
5 Social Determinants in Health Promotion Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
6 Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran
7 Non-Communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran
8 Iranian Center of Excellence in Health Management, Tabriz University of Medical Sciences, Tabriz, Iran
9 Department of Public Health, Zabol University of Medical Sciences, Zabol; Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran
|Date of Web Publication||4-Jan-2019|
Zabol University of Medical Sciences, Zabol; Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran
Source of Support: None, Conflict of Interest: None
Objective: Testicular cancer (TC), although it is one of the most unusual cancers, seems to be increasing. There is no accurate information on the incidence of this cancer in Iran. The present study is conducted to evaluate the incidence rates of TC in Iran. Methods: A systematic search was conducted on all published studies of TC incidence using Medline/PubMed, Scopus, Embase, Web of Science, Google Scholar and four Iranian databases (Scientific Information Database, MagIran, IranMedex and IranDoc) until June 2018. This systematic review was done according to the preferred reporting items for systematic reviews and meta-analyses. Result: The database searching yielded 132 potentially relevant studies. A total of 11 studies were included in the study. The results of the random-effects model were demonstrated that the age-standardised rate (ASR) of TC was 1.13, 95% confidence interval (0.97–1.29) among Iranian males. Conclusion: ASR for TC in Iran is lower than the world average; however, it has a higher incidence than other Asian countries.
Keywords: Incidence, Iran, systematic review, testicular neoplasms
|How to cite this article:|
Hassanipour S, Ghorbani M, Derakhshan M, Fouladseresht H, Mohseni S, Abdzadeh E, Riahi S, Arab-Zozani M, Delam H, Salehiniya H. The incidence of testicular cancer in Iran from 1996 to 2017: A systematic review and meta-analysis. Adv Hum Biol 2019;9:16-20
|How to cite this URL:|
Hassanipour S, Ghorbani M, Derakhshan M, Fouladseresht H, Mohseni S, Abdzadeh E, Riahi S, Arab-Zozani M, Delam H, Salehiniya H. The incidence of testicular cancer in Iran from 1996 to 2017: A systematic review and meta-analysis. Adv Hum Biol [serial online] 2019 [cited 2019 Dec 16];9:16-20. Available from: http://www.aihbonline.com/text.asp?2019/9/1/16/249525
| Introduction|| |
Testicular cancer (TC), although it is one of the most unusual cancers, seems to be increasing. Age-standardised rate (ASR) of TC is 1.5 in 100,000 worldwide. The incidence of this disease in developed countries was higher than in developing countries (5.2 per 100,000 vs. 0.7 per 100,000). The incidence of this cancer has increased in recent years in the United States and several other countries. The most common areas for this cancer are Western and Northern Europe (8.7 per 100,000 for Western Europe and 7.2 per 100,000 for Northern Europe). The lowest level of this cancer has been detected in Central Africa with ASR <0.2 per 100,000., Cancer does not have a high mortality rate, and according to the reported death rate, its ASR is around 0.3 per 100,000 worldwide. Known risk factors for TC are limited. Possible risk factors for this cancer include undescended testicle, familial history of TC and HIV infection.,, Undescended testicle is one of the main risk factors for TC. The condition occurs when testicles do not move from inside the abdomen to the outside of the body in childhood. Another possible risk factor for TC is family history, so that cancer in the father or in the brother will increase the odds of developing TC.,, Other risk factors, such as HIV infection and lentil disease, are the subject of this cancer;, however, further studies are needed. Most of the TCs occur between the ages of 20 and 34 years. The average age at detection of TC is 33 years but can be observed at any age, such as childhood or aging., Due to the current treatment of this disease, survival has been reported to be desirable. TC in Iran is higher than neighbouring areas. Crude rate in Iran is equal to 1.9 and ASR equal to 1.7. This cancer is one of the most common urological cancers, so that a study in Iran showed that 7% of urological cancers were associated with TC. Studies on the epidemiology of cancer in Iran are limited in general. According to reports, TC is not one of the major cancers in Iran. There is no complete and accurate information on the incidence of this cancer in Iran, and studies have revealed the incidence of this cancer in different regions. Precise information on the incidence of this cancer is necessary for planning. Therefore, this study was conducted to determine the ASR of TC in Iran through a systematic review and meta-analysis.
| Methods|| |
The systematic review and meta-analysis were designed in 2018 and undertaken in accordance with the preferred reporting items for systematic reviews and meta-analyses guideline.
Search strategy of systematic reviews
A literature search of published studies was conducted using international databases such as Medline/PubMed, Scopus, Web of Science, Google Scholar and Embase for English papers and Iranian databases such as Scientific Information Database (www.sid.ir), MagIran (www.magiran.com), IranMedex (www.barakatkns.com) and IranDoc (www.irandoc.ac.ir), for Persian papers.
The Medical Subject Headings keywords included 'Testicular Neoplasms', 'T Testicular cancer', 'Testicular Tumour', 'Cancer of T Testicular', 'Neoplasms of Thyroid', 'Testis Cancer', 'Testis Neoplasm', 'Testis Tumour', 'Epidemiology', 'Incidence' and 'Iran'. The obtained papers were imported into an EndNote X7 (Thomson Reuters, Carlsbad, CA, USA) library, and the duplicates were removed. No language and time limitations were considered.
Inclusion and exclusion criteria
All studies with results of ASR of TC and reports of Iranian populations were included in this review. Furthermore, studies with following criteria were not considered in this review; studies which reported prevalence rate, studies with inadequate sample size and other types of articles (all type of conference abstracts, poster papers, letters, comments and editorial).
To assess the quality of the articles, a checklist prepared by The Joanna Briggs Institute was used. The purpose of this appraisal is to assess the methodological quality of a study and to determine the extent to which a study has addressed the possibility of bias in its design, conduct and analysis. All papers were evaluated on the basis of data relevance and methodological rigor. The results of quality assessment are presented in [Table 1].
|Table 1: Joanna Briggs Institute critical appraisal checklist applied for included studies|
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Risk of bias across studies
Random-effects model was used for minimising risk of bias across the studies.,
STATA version 12.0 (Stata Corp LP, College Station, TX, USA) software was used to perform all analysis. Statistical heterogeneity between the results of obtained studies was assessed using Cochran's Q statistic (with a significance level of P ≤ 0.1) combined with I2 statistic (with a significance level of >50%). The meta-analysis was conducted with a random-effects model (with inverse variance method) in the studies with significant heterogeneity (P ≤ 0.1 and I2 ≥50%).
| Results|| |
Description of literature search
The database, grey literature searches and hand searching yielded 132 potentially relevant studies. In total, 81 unique studies were reviewed and 37 studies were entered into the second stage of evaluation. Overall, our review included 11 unique studies. Study retrieval and selection has been outlined in [Figure 1]. Some studies were excluded from the review due to not being relevant to the topic (n = 46), incorrect study population (n = 14), inadequate data (n = 7) and duplicate study (n = 3). The flowchart of the included studies in this review has been shown in [Figure 1].
|Figure 1: Flowchart of the included eligible studies in the systematic review.|
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Description of the included studies
The included studies were published from 2003 to 2016. Based on geographical locations, three studies were conducted in all states of Iran,,, two in Fars Province,, two in Ardabil Province,, one in East Azerbaijan Province, one in Semnan Province, one in Kerman Province and one in Shahroud city. All the studies have reported ASRs. The main characteristics of the selected studies are presented in [Table 2].
The results of individual studies
The highest ASR was reported from Shahroud city between 2000 and 2010 (2.18 per 100,000). The lowest ASR was reported from Fars Province between 1998 and 2002 (0.4 per 100,000).
The results of meta-analysis
The results of the random-effects model were demonstrated that the ASR of TC was 1.13, 95% confidence interval (0.97–1.29) among Iranian males. In addition, the results of Cochran's test showed the heterogeneity of the studies (Q = 610.5, df = 12, I2 = 98%, P < 0.001). The forest plots of the random-effects meta-analysis for ASR of TC in Iran are presented in [Figure 2].
|Figure 2: Forest plot of the random-effects meta-analysis for age-standardised rate of testicular cancer in males in the Iran.|
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Publication bias was assessed using Egger's tests. Results of Egger's tests showed lack of publication bias (P = 0.165).
| Discussion|| |
Cancer is the third case of death in Iranian population. Little studies have been done on the epidemiology of cancer in developing countries such as Iran.,,,,, Significant differences have been observed between the incidence of this cancer in developed and developing regions. This difference could be due to the exposure of people with potential risk factors or more accurate reporting in developed regions.,, The result of this study showed that ASR of TC in Iranian male has a low global average (1.13 per 100,000). Compared to other parts of Asia, Iran has a relatively high incidence. The highest incidence in Asia is related to Western Asia (ASR of 1.7 per 100,000), while in the East Asia region (0.5 per 100,000), it has a low incidence. In the neighbouring countries of Iran, Turkey has a relatively ASR (3.2 per 100,000). This difference can be due to environmental contexts, familial history, diagnostic methods and lifestyle., In a study that examined the role of the social development index and TC in Asia, there was a positive and significant correlation between this index and the ASR of TC in Asian countries (r = 0.298, P = 0.009).
The results of our study showed that the highest ASR of TC in Iranian males was in Shahroud city (2.18 in 100,000). The high incidence rate in this province can be attributed to the demographic characteristics of people living in this area, lifestyle, diet, genetics, exposure to more likely risk factors and more accurate reporting of TC cases., According to the results of our study, the lowest rate of ASR in TC was in Fars Province (0.4 per 100,000). One of the possible reasons for this issue can be low reporting and more cases of other cancers in the area. The findings in this province in recent years also confirm this finding., According to the studies conducted in Fars Province, TC has been found to be <0.5 per 100,000 in all studies.
| Conclusion|| |
Based on our findings, ASR for TC in Iran is lower than the world average; however, it has a higher incidence than other Asian countries.
The present study was financially supported by Guilan University of Medical Sciences, Rasht, Iran.
Financial support and sponsorship
The present study was financially supported by Guilan University of Medical Sciences, Rasht, Iran
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
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