|Ahead of print
Incidence and age-standardized rates of pancreatic cancer in Sri Lanka from 2001 to 2010: An analysis of national cancer registry data
Umesh Jayarajah, Isuru Almeida, Ashan Fernando, Sanjeewa Seneviratne, Dharmabandhu Nandadeva Samarasekera
Department of Surgery, University of Colombo, Sri Lanka
|Date of Submission||18-Mar-2019|
|Date of Decision||01-Jul-2019|
|Date of Acceptance||01-Apr-2020|
Dharmabandhu Nandadeva Samarasekera,
Department of Surgery, University of Colombo
Source of Support: None, Conflict of Interest: None
Background: Varying trends in the incidence of pancreatic cancer (PC) are observed in many Asian countries. This study aimed at describing the incidence and age-standardized rates of PC in Sri Lanka from 2001–2010.
Methods: A retrospective cohort evaluation of patients with PC from 2001 to 2010 was performed using the population-based data published by the Sri Lanka National Cancer Registry. The trends in the incidence of PC was analyzed by age and sex using joinpoint regression analysis.
Results: A total of 808 PC patients studied from 2001–2010, of which males were 438 (54.2%). The mean (±standard deviation) age of the total population was 55.7 (±13.8) years [males = 56.5 (±13.3) vs. females = 54.8 (±14.3), P=0.07]. The World Health Organization (WHO) age-standardized incidence of PC in Sri Lanka increased marginally from 0.44 per 100,000 in 2001 (95% confidence interval (CI) = 0.34-0.54) to 0.58 per 100,000 in 2010 (95% CI = 0.46-0.69) which is a 1.3-fold increase (P < 0.05 for trend) with an estimated annual percentage change (EAPC) of 3.5 (95% CI = 0.5-6.6). The proportional increase in incidence was more significant in females compared to males. The analysis of the overall cohort rates of PC in Srilanka between 2001–2010 showed the highest rates in the 60-70-year category with an EAPC of 5.06 (95% CI = 1.3–9.0).
Conclusion: In our study, we found that there was a marginal rise in the incidence of PC in Sri Lanka with a higher proportional increase in females compared to males.
Keywords: Age-standardized rate, incidence, national cancer registry, pancreatic cancer, pancreatic neoplasms, Sri Lanka
Key Message: The incidence of pancreatic cancer remains relatively low in Sri Lanka at approximately 0.5 per 100,000 population, although it appears to have increased marginally over the study period of 2001-2010.
|How to cite this URL:|
Jayarajah U, Almeida I, Fernando A, Seneviratne S, Samarasekera DN. Incidence and age-standardized rates of pancreatic cancer in Sri Lanka from 2001 to 2010: An analysis of national cancer registry data. Indian J Cancer [Epub ahead of print] [cited 2020 Oct 20]. Available from: https://www.indianjcancer.com/preprintarticle.asp?id=297019
| » Introduction|| |
Pancreatic cancer (PC) is the seventh most leading cause of death from cancer in both men and women globally. Pancreatic cancer has caused more than 432,000 deaths globally in 2018, and the number of deaths was close to the number diagnosed (n = 459,000). In 2012 and 2018, PC was ranked as the 11th and 14th most common cancer worldwide.,, It is the 5th and 4th common cause of cancer mortality among males and females, respectively, in developed countries., Due to the poor prognosis associated with pancreatic malignancies, the incidence rate of pancreatic cancer is almost equal to its mortality rate.,
The incidence of pancreatic cancer has shown variations across different populations. Incidence rates for pancreatic cancer in 2018 were highest in Europe and North America (9.5–9.9 per 100,000 age-standardized population in males), and the lowest rates (1.1–1.4 per 100,000 population in males) were seen in Eastern Africa and South-Central Asia. Increasing incidence has been shown in Southeast Asian countries, including Singapore (in both men and women), Thailand (in women), and the Philippines (in men and women). So far, there has been limited data from the South Asian region, which includes Sri Lanka.
Cancer registries are the primary source of cancer data in high-income countries. Data from these registries are a significant resource in cancer control efforts. These registries are essential to study the trends in cancer epidemiology and to monitor and predict changes in cancer incidence and survival. In Sri Lanka, the National Cancer Control Program (NCCP) has been collecting island-wide cancer data since 1985. Over the last three decades, the coverage has gradually increased, and as of 2014, it is estimated to include at least 80% of all cancers diagnosed in Sri Lanka. These include all cancers treated at national cancer institutions and other major government and private hospitals and pathology laboratories. This study aimed to describe the patterns in the incidence and age-standardized rates of pancreatic cancer in Sri Lanka based on the data from the NCCP. Furthermore, the age and sex-specific differences in PC rates were assessed. Further, we compared our results with other cancer registries from South Asia and with migrant South Asian populations living in the United States, United Kingdom, and Singapore.
| » Methods|| |
The cancer-related details of all patients diagnosed with pancreatic cancer between 01/01/2001 and 31/12/2010 were retrieved from the published data by the National Cancer Control Program of Sri Lanka. The classification of PC was based on the International Classification of Diseases (ICD)-10 system (C25). The data were analyzed based on age, sex, and histology type. The age-standardized rates of PC per 100,000 population were calculated for each year by sex, using the World Health Organization (WHO) age-standardized populations. Also, the age group and sex-specific rates were calculated for each year under consideration. Age (in years) categories were classified as less than 45, 45–59, 60–74, and ≥75. We did not do any data cleaning as it had already been done by the NCCP. Rates were calculated based on WHO age standardization.
The trends in the incidence of PC were analyzed by Joinpoint Regression Analysis, which is useful to detect points where a statistically significant change over time in the linear slope of the trend occurred. This analysis starts with the minimum number of joinpoints and tests whether one or more joinpoints were statistically significant. Joinpoint tests of significance use a Monte Carlo permutation method. In the final model, each joinpoint indicates a statistically significant change in trend. We computed an estimated annual percentage change (EAPC) for each of those trends using generalized linear models, assuming Poisson distribution. The rate and the direction of change in incidence was calculated and P values < 0.05 were considered statistically significant. The Joinpoint Software Version 4.3 was used for Joinpoint regression analysis. This study follows a similar methodology of previously published reports on the incidence of breast, thyroid, esophageal, and colorectal cancer in Sri Lanka.,,,
A comparison with other countries in South Asia and migrant South Asian populations using data from specific cancer registries was also made in both population and hospital data.
| » Results|| |
This study included a total of 808 pancreatic cancers diagnosed over a 10-year study period, i.e., 2001–2010. The majority of the cancers were in males (n = 438, 54.2%) with a male to female ratio of 1.2: 1. The mean (± standard deviation (SD)) age of the total study population was 55.7 (±13.8) years (males = 56.5 (±13.3) vs. females = 54.8 (±14.3), P = 0.07). The highest incidence of pancreatic cancers was observed in the 65–69 age group. The overall incidence was 1.8 per 100,000 population, 2.0 per 100,000 males and 1.6 per 100,000 females, respectively.
The most common histological pattern of PC was carcinoma not specified, seen in 41.3% of the patients. The adenocarcinoma in 325(%) and other variants of adenocarcinoma were seen in 63 (13.3%) of the patients. The other histological types of PC (viz. squamous cell carcinoma, adenosquamous carcinoma, islet cell carcinoma, neuroendocrine tumors, and pancreatoblastoma) were seen in 18.1% (n=86).
In the majority of the PC patients, the location of the tumor was not available (n = 513, 63.5%). In individuals where data was available, the most common sites included the head of the pancreas in 270 (91.5%), the body of the pancreas in 8 (2.7%), the tail of pancreas in 2 (4.0%), duct involvement in 3 (1%) and overlapping lesions of the pancreas (n = 2, 0.7%).
The WHO age-standardized incidence of pancreatic cancer in Sri Lanka was observed to have increased significantly from 0.44 per 100,000 in 2001 (95% confidence interval (CI) = 0.34–0.54) to 0.58 per 100,000 in 2010 (95% CI 0.46–0.69) which is a 1.3-fold increase (P < 0.05 for trend) [Figure 1]. This increase translates into an estimated annual percentage change (EAPC) of 3.5 (95% CI = 0.5–6.6). The proportional increase in incidence was greater for females (from 0.4 to 0.6 per 100,000 population, a 1.5-fold increase, P > 0.05 for trend) compared with males (from 0.47 to 0.56, a 1.2-fold increase, P > 0.05 for trend).
|Figure 1: Joinpoint regression curve for WHO age standardized incidence rates for pancreatic cancer per 100,000 overall population in Sri Lanka 2001–2010|
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The analysis of the overall cohort in terms of the age-related incidence of pancreatic cancer revealed a maximum increasing trend in the 60-74 years category with an EAPC of 5.06 (95% CI = 1.3-9.0). The pattern was statistically significant (P < 0.05). Interestingly, the age category 0-44 years showed a decreasing trend, while all other age groups showed increasing trends, none of which were statistically significant [Figure 2]. A similar pattern was seen in males where a decreasing trend in the incidence was seen in the 0–44 year age category and increasing trend in other groups. The maximum increase in rate was observed in ≥75 years of age group with an EAPC of 8.5 (95% CI = 0.6-17.1), and this trend was statistically significant (P < 0.05) [Figure 3]. In females, however, a decreasing trend in the incidence was noted in both 0–44 and ≥75-year categories. Furthermore, in the 60–74 year category, a more significant increase in direction was noted in the latter half of the study period from 2006 onwards [Figure 4].
|Figure 2: Joinpoint regression curve for pancreatic cancer incidence by age category in per 100,000 overall population in Sri Lanka 2001–2010|
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|Figure 3: Joinpoint regression curve for pancreatic cancer incidence by age category in males per 100,000 population in Sri Lanka 2001–2010|
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|Figure 4: Joinpoint regression curve for pancreatic cancer incidence by age category in females per 100,000 population in Sri Lanka 2001–2010|
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| » Discussion|| |
According to the data from the national cancer registry, the incidence of PC in Sri Lanka appears to have increased by approximately 30% over the 10-year study period. However, this increase in terms of absolute numbers is small and may be due to the improvement of the coverage of the national cancer data, better diagnosis, and reporting.
A comparison with other countries of South Asia showed a wide range of variation in the incidence of pancreatic cancer. The overall age-standardized incidence rates among both males and females were highest in India and lowest in Sri Lanka [Table 1]. The highest incidence was seen in Indian males from 2003 to 2007. The overall incidence in Indian males was higher than females.
|Table 1: Comparison of age-standardised rates of pancreatic carcinoma in different South Asian populations|
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Many studies have compared PC rates in migrant South Asian population with their native counterparts [Table 1].
All migrant population from the respective countries had considerably higher age-standardized rates of pancreatic cancer than their native counterparts. The highest rates were seen among UK South Asians followed by USA Indians and Pakistanis. Similar to the native population, ASR was lower among females compared to males in migrant population [Table 1].,,,,,
Interestingly, a wide range of variations in PC incidence rates was seen between native South Asian and migrant populations.,,,,, Remarkably, there seems to be an increased incidence of pancreatic cancer in the migratory population of South Asians in the developed countries than their native population.,,,,, The low rates in India compared with South Asians in UK, USA, and Singapore may be due to early cancer detection methods, better awareness programs, and a low threshold for screening for pancreatic cancer.,,,,, There is also some evidence to show that migratory population seek health care more readily. The higher rates of PC overall observed among South Asians migrants living in the UK, USA, and Singapore may be due to acculturation, as seen for other ethnic groups when they migrate. Similarly, other cancers in Asian groups in the USA have shown similar patterns.,
Although the national pancreatic cancer data from Sri Lanka had a nationwide coverage, registries in other South Asian countries during the study period had regional population-based registries such as population-based cancer registry (PBCR) of Mumbai from India and Karachi Cancer Registry from Pakistan [Table 1].,,,,, Although there are limitations, we used these regional data for comparison due to the unavailability of nationwide data from those countries during the study period.
There were several limitations in our study. There is difficulty in obtaining a histological diagnosis of pancreatic cancer in patients with inoperable disease and such patients may have been missed. The coverage of pancreatic cancer data collection may have increased gradually over the study period which probably has contributed to the small observed increase in the pancreatic cancer incidence. Another possible limitation of incidence data gathered from 2001 to 2010 includes the civil war in the northern and eastern parts of the country during 1983–2009. Thus, during this period, access to health care would have not been uniform in these parts of the island and the number of pancreatic cancers that were reported from those regions may not have been accurate. Furthermore, NCCP data did not include many other important information that would have helped to identify possible reasons for the observed trends in the incidence of PC in Srilanka. For instance, tumor biological characteristics, prevalence of smoking, diabetes, and other possible risk factors were not available in the NCCP database. Collection of such information in the future may help to understand the reasons for observed increases in incidence better. Regardless, NCCP data constitutes the largest and most comprehensive database on pancreatic cancer in Sri Lanka. While acknowledging the above limitations, these findings may help to initiate further studies to understand the patterns of PC in Sri Lanka.
| » Conclusion|| |
In this study, analysis of the national cancer data base from 2001 to 2010 showed that there is a marginal increase in the incidence of pancreatic cancer. The proportional increase in incidence was more significant in females compared to males.
Ethics approval and consent to participate
The ethical approval for this study was obtained from the Ethics Review Committee of the Faculty of Medicine, Colombo, Sri Lanka (EC 18-064). As only anonymised previously collected data were obtained from the National Cancer Registry for analyses, no patient consent process was involved.
The authors wish to thank Mr Pragatheeshkumar Sriskantharajah for providing his expertise in editing the artwork.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]