Years of life lost due to malignant neoplasms of the digestive system in Poland in the years 2000–2014

Abstract

Background

Every fourth death that occurs in Poland is caused by a malignant neoplasm. A particularly negative epidemiological situation relates to colorectal cancers; in 2015 they constituted the fifth most important cause of years of life lost (YLL) in Poland.

Objective

We aimed to analyse YLL due to malignant neoplasms of the digestive system in Poland in between 2000 and 2014.

Methods

The study material included a database containing information gathered from 5,601,568 death certificates of Poles who died in 2000–2014. YLLs were calculated with the use of the standard expected years of life lost index (SEYLL).

Results

In the 15-year study period, malignant neoplasms of the digestive system contributed to 213,041 deaths in males and 177,644 deaths in females, which corresponded to a loss of 158.6 years per 10,000 men and 105.3 years per 10,000 women. Neoplasms of the large intestine (23.6%), stomach (22.0%) and pancreas (17.4%) contributed the most. A time trend analysis revealed (p < 0.05) a growing tendency of YLLs due to neoplasms of the large intestine and pancreas, and a decreasing trend due to neoplasms of the stomach.

Conclusion

Malignant neoplasms of the digestive system, especially of the large intestine, are becoming a more common cause of premature mortality in Poland.

Key points

 Summarize the established knowledge on this subject.

• Years of life lost (YLL), a component of disability-adjusted life years (DALY), helps to assess socioeconomic aspects of premature mortality.

• Standard expected years of life lost (SEYLL) is a measure of YLLs that enables the comparison of epidemiological situations between different populations.

• According to the Global Burden of Disease study, malignant neoplasms of the large intestine, rectum and anus were, in 2015 in Poland, the 10th most important cause of DALYs, and also the fifth most important cause of YLLs.

What are the significant and/or new findings in this study?

• Malignant neoplasms of the digestive system are becoming a more common cause of premature mortality in Poland. Men who died due to these diseases in the years 2000–2014 lost on average 20.7 years of life, whereas women lost 17.6 years.

• A particularly negative trend can be observed in malignant neoplasms of the colon. The number of YLLs due to this cause is still increasing (p < 0.05) and it has exceeded mean values noted by the European Union.

Introduction

The incidence rate of malignant neoplasms in Poland is lower than the mean value for European Union (EU) countries. However, its constantly increasing tendency is an alarming phenomenon. In the year 2000, the incidence rate of malignant neoplasms for the Polish population was 300.3 per 100,000 population, whereas in 2013, it was as high as 411.5. At those times, the mean rates for EU countries were 448.6 and 556.0, respectively.¹ Also, the mortality rate for Poland, which is much higher than the mean value for EU countries, is of a concern. According to Eurostat, in 2014, standardized death rates (SDRs) due to malignant neoplasms for Poland were 427.8 per 100,000 men and 233.4 per 100,000 women, whereas in EU-28 countries, the mean respective values were 361.0 and 207.7.²

A particularly negative situation is noted in the group of colorectal cancers. Mortality rates due to this cause in Poland are higher than these observed in EU-28 countries (30.5 vs. 24.0 per 100,000 males and 15.4 vs. 13.6 per 100,000 females in 2014). Besides, the time trend analysis shows its less rapid decrease, particularly in inhabitants younger than 65 years (−0.05% vs. −0.2% in males and −0.04% vs. −0.1% in females yearly).³ In 2014, the percentage of deaths caused by colorectal neoplasms in the Polish population was 12.2% in males and 11.6% in females.⁴

An analysis conducted by the Global Burden of Disease (GBD) study showed that of all chronic diseases, malignant neoplasms of the large intestine, rectum and anus were, in 2015 in Poland, the 10th most important cause of disability-adjusted life years (DALYs), and also the fifth most important cause of prematurely lost years of life (YLL).^5,6

Neoplasms of other organs of the digestive system (i.e. the stomach and pancreas) are another highly important oncological causes of mortality in the Polish population. In 2014, they contributed to 6.4 and 4.7% of deaths in males and 4.4 and 5.9% of deaths in females, respectively.⁴

The aim of the study was to analyse YLLs due to premature mortality caused by malignant neoplasms of the digestive system in Poland in the years 2000–2014.

Materials and methods

The study was based on a data set containing information gathered from 5,601,568 death certificates of Poles who died in the years 2000–2014, provided by the Central Statistical Office in Poland. Deaths due to malignant neoplasms of the digestive system (i.e. coded as C15–C26 according to the International Statistical Classification of Diseases and Related Health Problems, 10th revision) were subject to an analysis.

Calculated mortality rates were standardized for age with the direct method, considering the European population (updated in 2013) as referential. Data on the size of the Polish population was obtained from the Local Data Bank of the Central Statistical Office in Poland.⁷ In order to analyse the number of YLL, the authors applied the standard expected YLL (SEYLL) index, calculated according to the method developed by Murray and Lopez:⁸

$$\text{SEYLL}=\sum _{\chi =0}^{\text{I}}{\text{d}}_{\chi }{\text{e}}_{\chi }^{*}$$

where: e*χ stands for a number of expected years of life that remain to be lived by the population that is at age x, dχ stands for a number of deaths at age χ, χ stands for the age when death occurred and I stands for the oldest age in a particular population.

The expected lifespan was determined on the basis of a table prepared by the World Health Organization in 2012, which assumes that life expectancy for both genders at age 0 is 86.02 years.⁹

The authors also applied the SEYLL per person (SEYLL_p) index, which is a ratio of SEYLL and the size of the population, calculated per 10,000 inhabitants, and the SEYLL per death (SEYLL_d) index, being a ratio of SEYLL and the number of deaths due to a particular cause; that is, it expresses the number of YLL calculated per one dead person.

The time trend analysis was conducted with the application of the joinpoint model and the use of Joinpoint Regression Program software provided by the US National Cancer Institute.¹⁰ The authors calculated annual percentage changes (APC) in particular periods and average annual percentage changes (AAPC) in the whole study period, with corresponding 95% confidence intervals (95% CIs) for the SDR and for the SEYLL_p index.¹¹

Results

In the years 2000–2014, malignant neoplasms of the digestive system were the cause of 390,685 deaths of Poles, accounting for 28.6% of deaths due to malignant neoplasms and also 7.0% of the total number of deaths that occurred in the Polish population in the analysed period. The number of male deaths was 213,041 (54.5%), whereas for females it was 177,644 (45.5%).

In subsequent years, the authors observed, both in males and females, an increase in the number of deaths due to the studied diseases (in males from 13,088 to 15,458 deaths in 2014 and in females from 11,375 to 12,393 deaths in 2000 and 2014, respectively) and their growing contribution to overall mortality in the Polish population (from 6.7% to 7.9% in males and from 6.6% to 6.9% in females in 2000 and 2014, respectively) (Table 1).

Table 1.

Deaths due to malignant neoplasms of the digestive system in Poland in the years 2000–2014 according to sex.

Year	Men		Women
	Number of deaths	% of all deaths of men	Number of deaths	% of all deaths of women
2000	13,088	6.7	11,375	6.6
2001	13,155	6.8	11,646	6.8
2002	13,522	7.1	11,502	6.9
2003	13,489	7.0	11,705	6.8
2004	13,710	7.0	11,460	6.8
2005	13,434	6.8	11,432	6.7
2006	13,855	7.0	11,509	6.7
2007	14,219	7.0	11,738	6.7
2008	14,451	7.1	12,216	6.9
2009	14,600	7.2	11,852	6.5
2010	14,787	7.4	12,125	6.8
2011	14,753	7.4	11,784	6.6
2012	15,360	7.6	12,530	6.9
2013	15,160	7.5	12,377	6.7
2014	15,458	7.9	12,393	6.9
Total	213,041	7.2	177,644	6.7

However, values of SDRs for both sexes decreased in this period. In 2000, the value of this measure in the group of men was 13.54 per 10,000 inhabitants, whereas in 2014 it was 12.02. With regards to females, the authors observed a decline from 7.82 to 6.36 (Figure 1).

Figure 1.

Standardized death rates (per 10,000 inhabitants) due to malignant neoplasms of the digestive system in Poland in the years 2000–2014 according to sex.

A joinpoint analysis of time trends for SDRs revealed that, in both groups, the decrease was statistically significant. In the male group, APC of SDR was −0.83 (95% CI: −1.0, −0.7; p < 0.05), whereas in females it was −1.51% (95% CI: −1.8, −1.3; p < 0.05).

It was noted that both at the beginning and the end of the study period, the death rate was increasing with age and its highest values were observed in the oldest population. Besides, the authors noted that the rate declined over the course of time in all age groups (Figure 2).

Figure 2.

Standardized death rates (per 10,000 inhabitants) due to malignant neoplasms of the digestive system in Poland in 2000 and 2014 according to age.

In 2014, in the group of deaths caused by malignant neoplasms of the digestive system, the highest share had neoplasms of the large intestine (C18) 26.4%, stomach (C16) 18.9% and pancreas (C25) 17.9%. Yet in 2000, the first, second and third positions were held by neoplasms of the stomach, large intestine and pancreas, which contributed to 24.7, 21.9 and 15.4% of deaths, respectively. While forming the group of colorectal neoplasms (C18–C21), the authors observed its dominance throughout the whole study period (in 2000, 34.8% and in 2014, 41.0%) (Table 2).

Table 2.

Deaths due to malignant neoplasms of the digestive system in Poland in 2000 and 2014 according to sex and cause.

Cause of death (according to ICD-10)		2000			2014
		Men	Women	General	Men	Women	General
Malignant neoplasm of oesophagus	C15	1111 (8.5%)	271 (2.4%)	1382 (5.6%)	1171 (7.6%)	344 (2.8%)	1515 (5.4%)
Malignant neoplasm of stomach	C16	3873 (29.6%)	2162 (19.0%)	6035 (24.7%)	3379 (21.9%)	1874 (15.1%)	5253 (18.9%)
Malignant neoplasm of small intestine	C17	80 (0.6%)	59 (0.5%)	139 (0.6%)	101 (0.7%)	100 (0.8%)	201 (0.7%)
Malignant neoplasm of colon	C18	2706 (20.7%)	2652 (23.3%)	5358 (21.9%)	3957 (25.6%)	3400 (27.4%)	7357 (26.4%)
Malignant neoplasm of rectosigmoid junction	C19	75 (0.6%)	106 (0.9%)	181 (0.7%)	295 (1.9%)	194 (1.6%)	489 (1.8%)
Malignant neoplasm of rectum	C20	1122 (8.6%)	996 (8.8%)	2118 (8.7%)	2047 (13.2%)	1272 (10.3%)	3319 (11.9%)
Malignant neoplasm of anus and anal canal	C21	470 (3.6%)	390 (3.4%)	860 (3.5%)	124 (0.8%)	122 (1.0%)	246 (0.9%)
Malignant neoplasm of liver and intrahepatic bile ducts	C22	993 (7.6%)	1078 (9.5%)	2071 (8.5%)	1084 (7.0%)	840 (6.8%)	1924 (6.9%)
Malignant neoplasm of gallbladder	C23	286 (2.2%)	1178 (10.4%)	1464 (6.0%)	225 (1.5%)	767 (6.2%)	992 (3.6%)
Malignant neoplasm of others and unspecified parts of biliary tract	C24	185 (1.4%)	262 (2.3%)	447 (1.8%)	318 (2.1%)	491 (4.0%)	809 (2.9%)
Malignant neoplasm of pancreas	C25	1917 (14.6%)	1847 (16.2%)	3764 (15.4%)	2464 (15.9%)	2519 (20.3%)	4983 (17.9%)
Malignant neoplasm of other and ill-defined digestive organs	C26	270 (2.1%)	374 (3.3%)	644 (2.6%)	293 (1.9%)	470 (3.8%)	763 (2.7%)
Total	C15-C26	13,088 (100%)	11,375 (100%)	24,463 (100%)	15,458 (100%)	12,393 (100%)	27,851 (100%)

ICD-10: International Statistical Classification of Diseases and Related Health Problems 10th revision.

Deaths due to malignant neoplasms of the digestive system in Poland in the years 2000–2014 contributed to 7,528,687.3 prematurely YLL (SEYLL). Of this number, 4,407,302.2 years were lost by males (58.5%) and 3,121,385.1 years by females (41.5%). In the whole study period, the average SEYLL_p was 158.6 years for males and 105.3 years for females. The value of SEYLL_d implied that a man who died due to a malignant neoplasm of the digestive system in Poland in the years 2000–2014 lost, on average, 20.7 years of life, and a woman lost 17.6 years (Table 3).

Table 3.

Lost years of life due to malignant neoplasms of the digestive system in Poland in the years 2000–2014 according to sex.

Year	Men			Women
	SEYLL	SEYLLp	SEYLLd	SEYLL	SEYLLp	SEYLLd
2000	283,566.2	153.0	21.7	206,835.6	104.9	18.2
2001	281,274.0	151.8	21.4	211,825.8	107.4	18.2
2002	288,086.5	155.7	21.3	206,355.6	104.7	17.9
2003	286,241.3	154.8	21.2	209,468.5	106.3	17.9
2004	289,345.9	156.7	21.1	203,102.2	103.1	17.7
2005	281,636.5	152.6	21.0	203,182.8	103.1	17.8
2006	286,636.4	155.6	20.7	204,201.1	103.7	17.7
2007	295,946.8	160.7	20.8	206,955.8	105.0	17.6
2008	295,263.9	160.3	20.4	211,449.4	107.2	17.3
2009	300,005.6	162.8	20.5	205,586.0	104.2	17.3
2010	301,062.0	161.4	20.4	210,305.6	105.8	17.3
2011	297,557.4	159.5	20.2	202,246.7	101.7	17.2
2012	309,493.8	166.0	20.1	216,580.1	108.9	17.3
2013	302,601.5	162.4	20.0	211,055.9	106.2	17.1
2014	308,584.4	165.7	20.0	212,234.2	106.9	17.1
Total	4,407,302.2	158.6	20.7	3,121,385.1	105.3	17.6

SEYLL: standard expected years of life lost; SEYLL_p: standard expected years of life lost per person (per 10,000 inhabitants); SEYLL_d: standard expected years of life lost per death.

The analysis of time trends for SEYLL_p revealed that the number of YLL due to neoplasms of the digestive system for general population statistically increased in the analysed period (APC = 0.4%; 95% CI: 0.2, 0.5; p < 0.05). By gender, only in males was the increase statistically significant (APC = 0.6%; 95% CI: 0.4, 0.8; p < 0.05), and in females it was insignificant (APC = 0.1%; 95% CI: −0.2, 0.3; p = not significant).

Of all malignant neoplasms of the digestive system, neoplasms of the large intestine contributed to the highest number of prematurely YLL: 1,775,043.5 (23.6%). Next were neoplasms of the stomach with 1,659,626.7 (22.0%) YLL and neoplasms of the pancreas with 1,307,676.0 (17.4%) YLL. These three diseases were responsible for 63.0% of all YLL due to neoplasms of the digestive system in the study period.

Of the above diseases, between 2000 and 2014, only neoplasms of the stomach contributed to a decrease in SEYLL_p value (from 45.2 to 36.3 years in males and 20.5 to 17.0 years in females) (Table 4). The joinpoint trend analysis showed that this tendency was statistically significant (in males, APC = −1.4%; 95% CI: −1.6, −1.2; p < 0.05; whereas in females, APC = −1.6%; 95% CI: −2.0, −1.1; p < 0.05) (Figure 3).

Table 4.

Standard expected years of life lost per person (per 10,000) due to malignant neoplasms of the digestive system in Poland in 2000 and 2014 according to sex and cause.

Cause (according to ICD-10)		2000			2014
		Men	Women	General	Men	Women	General
Malignant neoplasm of oesophagus	C15	14.7	2.7	8.5	14.8	3.5	8.9
Malignant neoplasm of stomach	C16	45.2	20.5	32.5	36.3	17.0	26.4
Malignant neoplasm of small intestine	C17	1.0	0.6	0.8	1.1	0.9	1.0
Malignant neoplasm of colon	C18	29.5	24.0	26.7	39.0	28.0	33.3
Malignant neoplasm of rectosigmoid junction	C19	0.7	0.9	0.8	3.0	1.6	2.3
Malignant neoplasm of rectum	C20	12.3	9.1	10.6	21.0	10.8	15.8
Malignant neoplasm of anus and anal canal	C21	5.1	3.6	4.3	1.4	1.1	1.2
Malignant neoplasm of liver and intrahepatic bile ducts	C22	11.8	10.1	10.9	12.3	7.2	9.7
Malignant neoplasm of gallbladder	C23	3.0	10.7	7.0	2.2	6.7	4.5
Malignant neoplasm of others and unspecified parts of biliary tract	C24	2.0	2.3	2.1	3.3	4.2	3.8
Malignant neoplasm of pancreas	C25	24.9	17.6	21.1	28.4	22.4	25.3
Malignant neoplasm of other and ill-defined digestive organs	C26	2.9	2.9	2.9	3.0	3.4	3.2
Total		153.0	104.9	128.2	165.7	106.9	135.4

ICD-10: International Statistical Classification of Diseases and Related Health Problems 10th revision.

Figure 3.

Time trends of standard expected years of life lost per person (per 10,000 inhabitants) for selected neoplasms of the digestive system in Poland in the years 2000–2014 according to sex.

SEYLL_p: standard expected years of life lost per person (per 10,000 inhabitants).

The authors observed an increase in the value of SEYLL_p due to malignant neoplasms of the large intestine, from 29.5 to 39.0 years in males and from 24.0 to 28.0 years in females. The pace of this trend in males changed from 2.7% (95% CI: 1.8, 3.6; p < 0.05) in 2000–2008 to 0.6% (95% CI: −0.7, 2.0; p < 0.05) in 2008–2014. In females, SEYLL_p grew at the annual rate of 0.9% (95% CI: 0.5, 1.3; p < 0.05) throughout the whole study period.

The value of SEYLL_p due to pancreatic neoplasms also increased, from 24.9 to 28.4 years in males and from 17.6 to 22.4 years in females. APC was 1.2% (95% CI: 0.8, 1.6; p < 0.05) for males and 1.6% (95% CI: 1.2, 2.0; p < 0.05) for females.

Discussion

Malignant neoplasms of the digestive system are responsible for about 7% of deaths in the Polish population yearly. In 2000–2014, the number of deaths due to these diseases was growing but SDR was characterized with a declining trend. This can be explained by the progressive aging of the Polish population and, to a lesser extent, by a slight improvement in the survival rates of patients with malignancies of the digestive system.^7,12

Colorectal, gastric and pancreatic neoplasms were dominant mortality causes of the Polish population in the analysed group of diseases.

In each studied year, the most YLLs were caused by colorectal cancers, and the analysis of this measure showed its continuous upward trend over time. It probably resulted from the progressive adverse changes in the lifestyle and dietary patterns of Poles.^13,14 Yet, the recognized risk factors for this malignancy include consumption of red meat, excessive alcohol intake, smoking nicotine and obesity.^15,16 Above all, a continuous increase in the amount of alcohol consumed by Poles is of a concern. In 2001, it amounted to 7.74 L per capita, while in 2013 it was 11.63 L.¹

Additionally, the reasons for a negative epidemiological situation related to colorectal neoplasms can be found in the ineffectiveness of the screening programme that has been carried out in Poland since 2000. It involves a foecal occult blood test performed annually and an endoscopic examination performed every 5–10 years in all inhabitants of Poland aged 50 years or older who visit selected health centres. People aged 55–64 years old are also sent personal invitations to colonoscopy. Unfortunately, the response rate to those invitations is highly unsatisfactory. In 2015, only 16.8% of the invited respondents arrived for examinations.^17,18

According to the GBD, in 2000, colorectal cancers were a cause of 58.3 prematurely YLL in the Polish population, calculated per 10,000 population. The mean value for EU countries was at that time 54.2 years. In 2010, the number of YLL in Poland increased up to 63.6, whereas in EU it decreased to 51.8.¹⁹ These data confirm a particularly negative epidemiological situation with regards to these neoplasms in Poland in comparison to the rest of Europe. The costs associated with the loss of income from the illness or premature death, and the treatment of this disease, constitute a significant economic burden for society. They have been estimated at 374 million EUR yearly, which is approximately 10.7% of all costs associated with malignant tumors in Poland.²⁰

Currently, there is no screening programme for the early detection of malignant neoplasms of the stomach in Poland. Yet, the mortality rate, as well as the number of YLLs to this disease, are constantly decreasing. According to the GBD, in 2000, the number of YLLs in Poland due to neoplasms of the stomach was 36.9 per 10,000 population, and in 2010 it was 32.0, while the values for EU countries were 31.7 and 24.9, respectively.¹⁹

A growing number of tests, performed in order to detect a symptomatic Helicobacter pylori infection, as well as attempts to eradicate the bacteria, which is considered the most potent risk factor for this disease, have probably contributed to an improvement in mortality rates due to stomach neoplasms.²¹ It is estimated that 84% of adults and 32% of children up to the age of 18 years in Poland are carriers of H. pylori bacteria. However, only 10–20% of them develop symptoms of the disease. Of this number, neoplastic changes are observed in 1% of the affected population.²²

Most likely, changes in dietary behaviors, especially the departure from traditional methods of food preparation through smoking and salt preservation, have also contributed to a decrease in mortality from gastric malignancies in Poland.²³ Besides, many researchers have mentioned a negative effect of underconsumption of fruit and vegetables, obesity and smoking nicotine.^24,25 The identification of modifiable risk factors may allow the creation of a programme for primary prevention of this disease, which still remains a global problem. Gastric neoplasms are the second most important cause of deaths due to malignant neoplasms in the world.²⁶

Of all malignancies, pancreatic neoplasms take 11th place globally with regard to their incidence and seventh with regard to mortality causes.²⁷ Geographical differences in mortality due to this disease most probably stem from smoking habits. Current smokers are most at risk, but the hazard persists for at least 10 years after quitting.^28,29 It must be pointed out that there is a declining trend in smoking cigarettes in Poland. In 2015, 24% of Poles declared daily smoking, while in 2009 it was 31% of the population and in 1993 it was 39%.¹ Genetic mutations are estimated to cause about 5–10% of pancreatic cancers. The importance of other factors is even more unclear, which poses a serious health hazard for all worldwide population.²⁷ According to the GBD, in Poland in 2000, the number of YLLs was not higher than the average value for EU countries (25.1 vs. 25.5), but the index was growing for both populations and in 2010 it was 27.3 and 28.4, respectively.¹⁹

Potential measures (including YLLs) rather than standard rates seem to better express social and economic effects of diseases, particularly those that contribute to a high mortality of people at a productive age. However, methodological differences in calculating YLLs observed in various publications make it difficult to compare the results between populations.^30–35 Among other limitations of the study is the use of a database that contains only primary causes of death, without including coexisting diseases. This may lead to an underestimation of the calculated values. The problem particularly concerns the oldest members of the population who are often characterized by the phenomenon of multimorbidity. It should also be noted that some errors may have occurred while diagnosis of the cause of death was made or in placing appropriate disease codes on death certificate. However, analysis of this issue indicates that, in Poland, it primarily affects cardiovascular diseases. Yet, due to the nearly 100% completeness of the death registry, it remains the best indirect source of information on the health status of the population.^30,36

In conclusion, neoplasms of the digestive system pose a growing health problem in the Polish population. Males who died due to this cause in the years 2000–2014, lost on average 20.7 years of life, whereas females lost 17.6 years. A particularly negative trend can be observed in malignant neoplasms of the colon. The number of premature YLLs due to this cause is still increasing and has exceeded the mean values noted for EU countries. It is essential that we disseminate methods of early detection of this disease and implement educational programmes aimed at reducing its development through its risk factors. Further research aimed at determining risk factors for the most common malignancies of the digestive system is also needed.

Declaration of conflicting interests

None declared.

Funding

The work was supported by the Medical University of Łódź (grant number 502-03/6-029-07/502-64-113).

Informed consent

Not applicable.

Ethics approval

The Bioethics Committee of the Medical University of Lodz gave consent for the study to be conducted (No. RNN/183/17KE of 13th June, 2017).