Introduction
It is estimated that most regions and countries have undergone unprecedented demographic changes since the second half of the 20th century; as living standards and health conditions improved, the mortality and fertility rates have substantially declined.[1] The consequences of this include the deceleration of population growth, prolonged life expectancies and population ageing. In the 1960s, the global average annual population growth was 2.3%; however, in 2020, it has dropped to just 1.1%. The world population is projected to reach 9.7 billion by 2050,[2] and the global life expectancy is projected to increase by 4.4 years by 2040; life expectancy will reach 74.3 years for men and 79.7 years for women.[3] Approximately 15.9% of the global population will be older than 65 years by 2050, up from 9.3% of the population in 2020.[2]
As cancer is a disease of ageing, the median age for cancer diagnosis in developed countries is approaching 70 years of age, and nearly 70% of all cancer cases are expected to occur in individuals aged 65 and above by 2030.[4] Thus, the global burden of cancer will be significantly increased due to the growing geriatric population. Gastric cancer (GC) is the sixth most common cancer and the third most common cause of cancer-related death worldwide, with 1.089 million newly diagnosed cases and 0.769 million deaths in 2020.[5] The median age of GC diagnosis is 70 years. GC is a multifactorial disease, and the risk factors include Helicobacter pylori infection, ageing, smoking, high salt intake, and low dietary fruit and vegetable intake. The incidence of GC is twice as high in males as it is in females. The incidence and mortality rates vary widely by geography, with East Asia, Eastern Europe, Western Asia, and South America reporting the highest rates.[6]
Globally, the incidence and mortality rates of GC have declined since Helicobacter pylori was eradicated 50 years ago, and they are expected to continue to decline in the future due to improved living conditions and advancements in medical care.[7] However, the absolute numbers of new cases and deaths due to GC are increasing due to population growth and ageing.[8]
To forecast the new cases and deaths due to GC, we utilized the Global Cancer Observatory (GLOBOCAN) 2020 and the United Nations 2022 population projections and further analysed the geographic and temporal variations across ages and sexes. Forecasting the burden of GC will assist in comprehensively understanding global disparities, allocating medical resources effectively, and formulating targeted policies for the prevention, screening and treatment of GC.
Methods
Data sources
The definition of GC was based on the International Classification of Diseases - 10th Revision (ICD-10) code C16. The estimated number of new cases and deaths of GC in 185 countries in 2020 by age, sex, and country were obtained from the GLOBOCAN 2020 database (http://globocan.iarc.fr/) to estimate the rate [Supplementary Table 1, https://links.lww.com/CM9/B461].[9] The cancer incidence data were obtained from Volumes X to XI of Cancer Incidence in Five Continents (CI5). The CI5 volumes comprised cancer data on 5-year incidence reported by selected population-based cancer registries that covered regions within the five continents.[10] A total of 171 cancer registries containing the number of new cancer cases by year, age group, sex, and the corresponding population data were selected to estimate the trends in GC [Supplementary Table 2, https://links.lww.com/CM9/B461]. Both the GLOBOCAN database and the CI5 database were accessed from the International Agency for Research on Cancer.
The 185 countries were geographically grouped into the following 19 regions based on the United Nations geographical divisions: East Asia, Southeast Asia, South Central Asia, West Asia, North America, Central and South America, the Caribbean, Eastern Europe, Northern Europe, Western Europe, Southern Europe, East Africa, Central Africa, North Africa, West Africa, South Africa, Australia/New Zealand, and the Pacific Islands (including Melanesia and Micronesia/Polynesia). The World Population Prospect 2021, produced by the United Nations Population Division,[11] provides population estimates for 2020 to 2040 by age, sex, and region for 185 countries. According to the human development index (HDI) created by the United Nations development program,[12] the 19 regions are classified as regions of very high, high, medium, and low HDI.
Statistical analysis
To analyse the incidence and mortality of GC in 2020, we extracted the data coded as C16 of the ICD-10 from the data source. The crude incidence and mortality rates were calculated by region, sex (male/female) and age group (0–80 in 5 year increments, 85+ years). The temporal trends in the incidence and mortality of GC from 2020 to 2040 were examined by fitting a linear regression model with a large age group (0 to 39, 40 to 65 in 5 year increments, 70+ years) using the data from CI5 Volumes X to XI. Trends are expressed as annual percent changes (APCs).[13] The age-standardized incidence rates (ASIRs) and age-standardized mortality rates (ASMRs) per 100,000 person-years were calculated by using Segi's world standard population. The numbers of new cases and deaths from 2020 to 2040 were predicted by multiplying the projected incidence and mortality rates by the population from 2020 to 2040. The estimated numbers of GC cases and deaths were apportioned according to the change in risk and change in population, including the population size and age structure according to the methods described by Moller et al.[14,15]
For the convenience of comparisons across studies, the group under 40 years old, the group between 40 and 64 years old and the group over 65 years old are referred to as the young group, the middle-aged group and the elderly group, respectively, in the following sections.
Results
Trends in demographic transition
In the next 20 years, the world population will continue to grow at a slower pace, from 7.79 billion in 2020 to 8.55 billion by 2030 (an increase of 9.64% from 2020–2030) and to 9.19 billion by 2040 (an increase of 7.51% from 2030–2040). The population size for all age groups will increase during the two decades. The young group will increase from 4.94 billion in 2020 to 5.20 billion in 2040 (an increase of 5.26%), the middle-aged group will increase from 2.13 billion in 2020 to 2.66 billion in 2040 (an increase of 24.88%), and the elderly group will increase from 0.73 billion in 2020 to 1.33 billion in 2040 (an increase of 82.19%). The proportion of the three groups in the world population will change correspondingly from 63.35%, 27.31% and 9.34% in 2020 to 56.57%, 28.96% and 14.47% in 2040. The proportion of males and females will roughly be equal in the next two decades. It is expected that the sex ratio (male: female) in the young group will drop from 1.060 in 2020 to 1.050 in 2040, that in the middle-aged group will increase from 0.997 to 1.012 in 2040, and that in the elderly group will increase from 0.815 to 0.821 in 2040.
A slow-down in population growth has been observed in most regions of the world. The highest growth occurring in Africa and West Asia, whereas a continuous decline in population is occurring in East Asia, Eastern Europe and Southern Europe. The population will increase by 63.16%, 23.14%, 1.40% and 3.39%, respectively, by 2040 in regions with an HDI ranging from low to very high. However, the greatest variance will be observed in the young group. By 2040, the population of the young group is expected to increase by 55.43% and 6.93% in low and medium HDI regions, respectively, and decrease by 20.39% and 8.89% in high and very high HDI regions, respectively. During the demographic transition in the next 20 years, the population ageing in all regions will be severe and obvious. The elderly population will increase by 105.04%, 108.71%, 104.10%, and 41.45% in low, medium, high, and very high HDI regions, respectively [Supplementary Table 3, https://links.lww.com/CM9/B461 and Figure 1].
;)
Figure 1: Population changes in (A) young, middle-aged and elderly group, (B) males and females in the three age groups, and regions with a very high (C), high (D), medium (E), and low (F) HDI from 2020 to 2040.
Projection in new cases and deaths of gastric cancer
Trends of incidence and mortality rate
The incidence and mortality rates of GC show a persistent decrease through 2040 worldwide, with an APC of –0.57% for males and –0.65% for females. According to our prediction, the global ASIR and ASMR in 2020 were 11.19 and 7.73 per 100,000, respectively, which will decrease to 10.44 and 7.27 per 100,000 by 2030 and further decrease to 9.90 and 6.90 per 100,000 by 2040. Although the majority of countries had a decreasing trend in the GC incidence and mortality rate, the APC varied greatly by region, ranging from –9.80% in Western Asia to 0.41% in Eastern Africa. As HDI increases, the APC decreases in regions. In the next 20 years, the regions with the highest ASIR and ASMR will be found in East Asia, with expected changes from 22.7 and 14.8 per 100,000 to 22.6 and 14.8 per 100,000, respectively, and an APC of –0.05% for males and –0.27% for females. Meanwhile, the lowest ASIR and ASMR will be found in North America, with expected changes from 4.2 and 1.8 per 100,000 to 3.9 and 1.6 per 100,000, and an APC of –0.53% for males and –0.26% for females [Supplemental Table 4–6, https://links.lww.com/CM9/B461].
Trends of newly diagnosed cases and deaths
Due to population growth, the numbers of newly diagnosed cases and deaths of GC worldwide will continue to increase in the next 20 years. The number of newly diagnosed cases in 2020 was 1.09 million, but this is expected to increase to 1.35 million by 2030 and further increase to 1.63 million by 2040. The number of deaths in 2020 was 0.77 million, and this is expected to increase to 0.96 million by 2030 and 1.18 million by 2040. However, a slowdown in the growth of incident cases and deaths will be observed. Newly diagnosed cases and deaths will increase by 23.90% and 25.11% from 2020 to 2030, and 20.87% and 22.35% from 2030 to 2040, respectively [Tables 1 and 2].
Table 1 -
New cases of gastric cancer in different regions by age group, 2020–2040.
|
|
Total |
Male |
Female |
|
|
|
|
|
| Region |
Year |
Age <40 years |
40 years ≤Age<65 years |
Age≥ 65 years |
Age< 40 years |
40 years ≤Age<65 years |
Age ≥65 years |
Age<40 years |
40 years ≤Age<65 years |
Age≥ 65 years |
| World |
2020 |
26,191 (2.4) |
421,467 (38.7) |
641,445 (58.9) |
12,550 (1.7) |
288,154 (40.0) |
418,819 (58.2) |
13,641 (3.7) |
133,313 (36.1) |
222,626 (60.2) |
|
2030 |
22,744 (1.7) |
467,569 (34.6) |
859,122 (63.7) |
10,595 (1.2) |
319,059 (35.7) |
564,342 (63.1) |
12,149 (2.7) |
148,510 (32.6) |
294,780 (64.7) |
|
2040 |
19,837 (1.2) |
492,780 (30.2) |
1,118,390 (68.6) |
8957 (0.8) |
336,260 (30.9) |
744,005 (68.3) |
10,880 (2.0) |
156,520 (28.9) |
374,385 (69.1) |
| By HDI |
|
|
|
|
|
|
|
|
|
|
| Very high HDI |
2020 |
3963 (1.2) |
87,897 (25.8) |
248,450 (73.0) |
1683 (0.8) |
59,945 (27.1) |
159,188 (72.1) |
2280 (1.9) |
27,952 (23.4) |
89,262 (74.7) |
|
2030 |
3066 (0.8) |
87,766 (22.0) |
308,860 (77.3) |
1275 (0.5) |
60,079 (22.7) |
203,216 (76.8) |
1790 (1.3) |
27,686 (20.5) |
105,644 (78.2) |
|
2040 |
2419 (0.5) |
86,483 (18.9) |
367,629 (80.5) |
982 (0.3) |
59,243 (19.3) |
246,498 (80.4) |
1437 (1.0) |
27,239 (18.2) |
121,131 (80.9) |
| High HDI |
2020 |
11,399 (1.9) |
253,530 (43.2) |
321,969 (54.9) |
5139 (1.3) |
177,625 (44.6) |
215,256 (54.1) |
6260 (3.3) |
75,905 (40.2) |
106,713 (56.5) |
|
2030 |
9847 (1.4) |
258,521 (37.7) |
418,162 (60.9) |
4148 (0.9) |
181,261 (39.3) |
275,601 (59.8) |
5699 (2.5) |
77,260 (34.3) |
142,561 (63.2) |
|
2040 |
8917 (1.2) |
226,832 (30.2) |
516,254 (68.7) |
3537 (0.7) |
159,929 (31.6) |
342,932 (67.7) |
5379 (2.2) |
66,904 (27.2) |
173,322 (70.6) |
| Medium HDI |
2020 |
8737 (6.8) |
64,599 (50.1) |
55,623 (43.1) |
4580 (5.6) |
41,693 (50.9) |
35,680 (43.5) |
4157 (8.8) |
22,906 (48.7) |
19,943 (42.4) |
|
2030 |
9581 (6.1) |
72,399 (46.2) |
74,602 (47.6) |
4252 (4.4) |
46,247 (47.6) |
46,610 (48.0) |
5329 (9.0) |
26,152 (44.0) |
27,993 (47.1) |
|
2040 |
10,240 (5.5) |
79,156 (42.4) |
97,405 (52.1) |
3761 (3.3) |
50,306 (44.2) |
59,699 (52.5) |
6480 (8.9) |
28,850 (39.5) |
37,706 (51.6) |
| Low HDI |
2020 |
1994 (7.1) |
13,940 (49.5) |
12,249 (43.5) |
1110 (7.0) |
8009 (50.4) |
6763 (42.6) |
884 (7.2) |
5931 (48.2) |
5486 (44.6) |
|
2030 |
981 (2.6) |
21,645 (57.9) |
14,732 (39.4) |
535 (2.3) |
14,733 (62.7) |
8240 (35.1) |
446 (3.2) |
6912 (49.9) |
6492 (46.9) |
|
2040 |
465 (0.8) |
36,377 (66.1) |
18,217 (33.1) |
247 (0.7) |
26,917 (71.7) |
10,377 (27.6) |
217 (1.2) |
9460 (54.0) |
7840 (44.8) |
| Geographical regions |
|
|
|
|
|
|
|
|
|
|
| Northern America |
2020 |
930 (3.1) |
10,064 (33.8) |
18,770 (63.1) |
447 (2.5) |
6288 (34.6) |
11,435 (62.9) |
483 (4.2) |
3776 (32.6) |
7335 (63.3) |
|
2030 |
1017 (2.9) |
9841 (28.5) |
23,695 (68.6) |
474 (2.2) |
6030 (28.5) |
14,634 (69.2) |
542 (4.0) |
3812 (28.4) |
9061 (67.5) |
|
2040 |
1064 (2.8) |
10,307 (27.1) |
26,630 (70.1) |
478 (2.1) |
6218 (26.8) |
16,517 (71.2) |
586 (4.0) |
4089 (27.7) |
10,112 (68.4) |
| Eastern Asia |
2020 |
8421 (1.3) |
247,673 (38.0) |
395,770 (60.7) |
3851 (0.9) |
176,568 (39.3) |
269,218 (59.9) |
4570 (2.3) |
71,105 (35.2) |
126,552 (62.6) |
|
2030 |
5835 (0.7) |
270,106 (30.9) |
597,178 (68.4) |
2577 (0.4) |
193,548 (32.2) |
404,400 (67.3) |
3257 (1.2) |
76,558 (28.1) |
192,778 (70.7) |
|
2040 |
4279 (0.4) |
236,627 (21.7) |
850,740 (77.9) |
1875 (0.2) |
171,124 (22.6) |
585,096 (77.2) |
2405 (0.7) |
65,502 (19.6) |
265,644 (79.6) |
| Eastern Africa |
2020 |
1044 (10.5) |
4961 (49.9) |
3943 (39.6) |
629 (12.8) |
2373 (48.3) |
1911 (38.9) |
415 (8.2) |
2588 (51.4) |
2032 (40.4) |
|
2030 |
505 (3.9) |
7689 (59.5) |
4729 (36.6) |
298 (4.2) |
4520 (63.5) |
2301 (32.3) |
208 (3.6) |
3169 (54.6) |
2428 (41.8) |
|
2040 |
237 (1.2) |
13,090 (67.5) |
6077 (31.3) |
136 (1.2) |
8515 (72.8) |
3048 (26.1) |
101 (1.3) |
4574 (59.4) |
3029 (39.3) |
| Middle Africa |
2020 |
178 (5.3) |
1616 (48.3) |
1551 (46.4) |
85 (4.9) |
929 (53.7) |
717 (41.4) |
93 (5.8) |
687 (42.6) |
834 (51.7) |
|
2030 |
191 (4.1) |
2239 (48.6) |
2181 (47.3) |
88 (3.3) |
1482 (56.1) |
1072 (40.6) |
103 (5.2) |
757 (38.4) |
1109 (56.3) |
|
2040 |
203 (3.1) |
3210 (49.1) |
3129 (47.8) |
90 (2.2) |
2384 (58.2) |
1624 (39.6) |
113 (4.6) |
826 (33.8) |
1506 (61.6) |
| Northern Africa |
2020 |
781 (8.3) |
4315 (46.0) |
4283 (45.7) |
389 (7.2) |
2487 (46.0) |
2526 (46.8) |
392 (9.9) |
1828 (46.0) |
1757 (44.2) |
|
2030 |
663 (5.5) |
5535 (45.9) |
5865 (48.6) |
324 (4.2) |
3753 (49.1) |
3572 (46.7) |
339 (7.7) |
1782 (40.4) |
2294 (52.0) |
|
2040 |
578 (3.5) |
7256 (43.8) |
8724 (52.7) |
272 (2.4) |
5532 (48.6) |
5573 (49.0) |
306 (5.9) |
1724 (33.3) |
3151 (60.8) |
| Southern Africa |
2020 |
109 (5.9) |
894 (48.3) |
847 (45.8) |
57 (5.2) |
578 (52.7) |
461 (42.1) |
52 (6.9) |
316 (41.9) |
386 (51.2) |
|
2030 |
86 (3.6) |
1120 (47.2) |
1168 (49.2) |
44 (2.9) |
824 (55.5) |
618 (41.6) |
42 (4.7) |
295 (33.3) |
549 (62.0) |
|
2040 |
66 (2.1) |
1466 (46.4) |
1626 (51.5) |
33 (1.5) |
1184 (54.4) |
961 (44.1) |
33 (3.4) |
282 (28.8) |
665 (67.8) |
| Western Africa |
2020 |
525 (6.7) |
4211 (53.7) |
3113 (39.7) |
268 (6.2) |
2383 (54.9) |
1689 (38.9) |
257 (7.3) |
1828 (52.1) |
1424 (40.6) |
|
2030 |
533 (5.0) |
5608 (52.5) |
4542 (42.5) |
266 (4.0) |
3751 (56.8) |
2589 (39.2) |
267 (6.6) |
1857 (45.5) |
1953 (47.9) |
|
2040 |
546 (3.6) |
8026 (53.3) |
6480 (43.1) |
265 (2.6) |
6071 (59.5) |
3861 (37.9) |
281 (5.8) |
1955 (40.3) |
2619 (54.0) |
| Caribbean |
2020 |
125 (3.0) |
1465 (35.6) |
2530 (61.4) |
69 (2.8) |
934 (37.8) |
1471 (59.5) |
56 (3.4) |
531 (32.3) |
1059 (64.3) |
|
2030 |
135 (2.9) |
1598 (34.1) |
2948 (63.0) |
72 (2.6) |
1013 (36.7) |
1672 (60.6) |
63 (3.3) |
585 (30.4) |
1276 (66.3) |
|
2040 |
132 (2.5) |
1628 (30.7) |
3549 (66.8) |
67 (2.2) |
1024 (33.1) |
2000 (64.7) |
64 (2.9) |
604 (27.2) |
1549 (69.9) |
| Central America |
2020 |
819 (5.9) |
5453 (39.4) |
7553 (54.6) |
369 (4.9) |
2934 (39.3) |
4167 (55.8) |
450 (7.1) |
2519 (39.6) |
3386 (53.3) |
|
2030 |
640 (4.2) |
5833 (38.4) |
8718 (57.4) |
242 (3.1) |
3033 (38.2) |
4657 (58.7) |
398 (5.5) |
2800 (38.6) |
4061 (55.9) |
|
2040 |
477 (2.8) |
5988 (35.5) |
10,402 (61.7) |
147 (1.7) |
3017 (35.4) |
5362 (62.9) |
330 (4.0) |
2971 (35.6) |
5040 (60.4) |
| South-Eastern Asia |
2020 |
1570 (3.9) |
20,009 (50.3) |
18,184 (45.7) |
754 (3.1) |
12,800 (53.0) |
10,588 (43.9) |
816 (5.2) |
7209 (46.1) |
7596 (48.6) |
|
2030 |
1350 (3.0) |
19,603 (43.9) |
23,664 (53.0) |
571 (2.2) |
12,764 (48.4) |
13,013 (49.4) |
779 (4.3) |
6840 (37.4) |
10,650 (58.3) |
|
2040 |
1138 (2.4) |
18,553 (38.4) |
28,593 (59.2) |
415 (1.5) |
12,418 (45.2) |
14,669 (53.3) |
723 (3.5) |
6135 (29.5) |
13,924 (67.0) |
| South-Central Asia |
2020 |
7001 (6.8) |
49,350 (48.1) |
46,325 (45.1) |
3704 (5.5) |
32,545 (48.1) |
31,452 (46.5) |
3297 (9.4) |
16,805 (48.0) |
14,873 (42.5) |
|
2030 |
8337 (6.2) |
60,983 (45.2) |
65,725 (48.7) |
3638 (4.3) |
38,840 (45.5) |
42,955 (50.3) |
4698 (9.5) |
22,144 (44.6) |
22,770 (45.9) |
|
2040 |
9638 (5.5) |
74,715 (43.0) |
89,418 (51.5) |
3381 (3.2) |
46,320 (43.4) |
57,017 (53.4) |
6258 (9.3) |
28,395 (42.3) |
32,401 (48.3) |
| Western Asia |
2020 |
996 (4.7) |
9153 (43.0) |
11,130 (52.3) |
457 (3.4) |
5965 (44.8) |
6883 (51.7) |
539 (6.8) |
3188 (40.0) |
4247 (53.3) |
|
2030 |
1140 (4.5) |
12,872 (50.5) |
11,469 (45.0) |
481 (2.9) |
8631 (52.4) |
7362 (44.7) |
659 (7.3) |
4241 (47.1) |
4106 (45.6) |
|
2040 |
1331 (4.3) |
15,814 (51.0) |
13,845 (44.7) |
530 (2.6) |
10,635 (51.8) |
9349 (45.6) |
801 (7.6) |
5178 (49.4) |
4496 (42.9) |
| Eastern Europe |
2020 |
885 (1.4) |
23,874 (36.4) |
40,757 (62.2) |
320 (0.8) |
16,390 (41.1) |
23,215 (58.1) |
565 (2.2) |
7484 (29.2) |
17,542 (68.5) |
|
2030 |
619 (1.0) |
20,449 (32.0) |
42,833 (67.0) |
226 (0.6) |
14,160 (35.9) |
25,044 (63.5) |
393 (1.6) |
6289 (25.7) |
17,789 (72.7) |
|
2040 |
519 (0.8) |
19,715 (31.5) |
42,270 (67.6) |
185 (0.5) |
13,844 (35.2) |
25,285 (64.3) |
335 (1.4) |
5871 (25.3) |
16,985 (73.2) |
| Northern Europe |
2020 |
181 (1.6) |
2649 (23.2) |
8611 (75.3) |
83 (1.1) |
1712 (23.6) |
5445 (75.2) |
98 (2.3) |
937 (22.3) |
3166 (75.4) |
|
2030 |
168 (1.4) |
2346 (20.2) |
9102 (78.4) |
87 (1.2) |
1482 (19.9) |
5868 (78.9) |
81 (1.9) |
864 (20.7) |
3235 (77.4) |
|
2040 |
154 (1.3) |
2047 (17.8) |
9275 (80.8) |
87 (1.2) |
1263 (17.1) |
6048 (81.7) |
66 (1.6) |
784 (19.2) |
3227 (79.2) |
| Southern Europe |
2020 |
292 (1.0) |
7334 (24.1) |
22,782 (74.9) |
128 (0.7) |
4791 (25.8) |
13,623 (73.5) |
164 (1.4) |
2543 (21.4) |
9159 (77.2) |
|
2030 |
219 (0.7) |
6631 (21.5) |
24,015 (77.8) |
107 (0.6) |
4193 (22.2) |
14,599 (77.2) |
112 (0.9) |
2437 (20.4) |
9416 (78.7) |
|
2040 |
178 (0.6) |
5217 (16.6) |
26,064 (82.9) |
95 (0.5) |
3178 (16.5) |
15,985 (83.0) |
82 (0.7) |
2039 (16.7) |
10,079 (82.6) |
| Western Europe |
2020 |
427 (1.5) |
8031 (28.2) |
20,021 (70.3) |
217 (1.2) |
5508 (30.8) |
12,168 (68.0) |
210 (2.0) |
2523 (23.8) |
7853 (74.2) |
|
2030 |
322 (1.1) |
7299 (24.9) |
21,646 (74.0) |
140 (0.8) |
4973 (26.8) |
13,443 (72.4) |
183 (1.7) |
2325 (21.7) |
8203 (76.6) |
|
2040 |
242 (0.8) |
6671 (22.7) |
22,494 (76.5) |
86 (0.5) |
4507 (24.2) |
14,065 (75.4) |
157 (1.5) |
2164 (20.1) |
8429 (78.4) |
| Australia/New Zealand |
2020 |
70 (2.6) |
791 (29.6) |
1815 (67.8) |
36 (2.0) |
551 (30.6) |
1212 (67.4) |
34 (3.9) |
240 (27.4) |
603 (68.8) |
|
|
|
|
|
|
|
|
|
|
|
|
2030 |
66 (2.1) |
838 (26.2) |
2299 (71.8) |
36 (1.7) |
593 (27.6) |
1523 (70.8) |
30 (2.9) |
245 (23.3) |
777 (73.8) |
|
2040 |
55 (1.5) |
910 (25.2) |
2644 (73.3) |
31 (1.3) |
656 (27.3) |
1719 (71.4) |
24 (2.0) |
254 (21.1) |
925 (76.9) |
| South America |
2020 |
1705 (3.4) |
17,856 (36.0) |
29,986 (60.5) |
629 (2.1) |
11,376 (37.3) |
18,515 (60.7) |
1076 (5.7) |
6480 (34.1) |
11,471 (60.3) |
|
2030 |
1961 (3.7) |
18,482 (35.2) |
32,023 (61.0) |
589 (1.8) |
11,806 (36.2) |
20,230 (62.0) |
1371 (6.9) |
6676 (33.6) |
11,793 (59.4) |
|
2040 |
2176 (3.9) |
18,623 (33.3) |
35,073 (62.8) |
523 (1.5) |
11,933 (33.9) |
22,704 (64.6) |
1653 (8.0) |
6690 (32.3) |
12,368 (59.7) |
| Melanesia/Micronesia/Polynesia |
2020 |
34 (5.5) |
267 (43.0) |
320 (51.5) |
20 (5.4) |
160 (43.1) |
191 (51.5) |
14 (5.6) |
107 (42.8) |
129 (51.6) |
|
|
|
|
|
|
|
|
|
|
|
|
2030 |
39 (4.5) |
364 (42.1) |
461 (53.3) |
24 (4.6) |
223 (42.6) |
276 (52.8) |
15 (4.4) |
141 (41.4) |
185 (54.2) |
|
2040 |
39 (3.5) |
447 (39.6) |
644 (57.0) |
25 (3.8) |
278 (42.0) |
358 (54.2) |
14 (3.0) |
169 (36.1) |
285 (60.9) |
Data are shown as n (%). HDI: Human development.
Table 2 -
Deaths of gastric cancer in different regions by age group, 2020–2040.
|
|
Total |
Male |
Female |
|
|
|
|
|
| Region |
Year |
Age <40 years |
40 years ≤Age<65 years |
Age≥ 65 years |
Age< 40 years |
40 years ≤Age<65 years |
Age ≥65 years |
Age<40 years |
40 years ≤Age<65 years |
Age≥ 65 years |
| World |
2020 |
16,033 (2.1) |
271,818 (35.4) |
480,942 (62.6) |
7563 (1.5) |
184,768 (36.7) |
310,457 (61.7) |
8470 (3.2) |
87,050 (32.7) |
170,485 (64.1) |
|
2030 |
13,892 (1.4) |
301,778 (31.4) |
646,182 (67.2) |
6355 (1.0) |
204,808 (32.5) |
419,660 (66.5) |
7538 (2.3) |
96,970 (29.3) |
226,521 (68.4) |
|
2040 |
12,150 (1.0) |
317,851 (27.0) |
846,822 (72.0) |
5386 (0.7) |
215,727 (27.7) |
556,786 (71.6) |
6763 (1.7) |
102,124 (25.6) |
290,036 (72.7) |
| By HDI |
| Very high HDI |
2020 |
2090 (1.2) |
37,417 (22.2) |
129,352 (76.6) |
936 (0.9) |
25,401 (24.3) |
78,392 (74.9) |
1154 (1.8) |
12,016 (18.7) |
50,960 (79.5) |
|
2030 |
1609 (0.8) |
37,353 (18.5) |
162,562 (80.7) |
703 (0.5) |
25,447 (19.9) |
101,723 (79.6) |
905 (1.2) |
11,907 (16.2) |
60,839 (82.6) |
|
2040 |
1272 (0.5) |
36,760 (15.5) |
198,814 (83.9) |
545 (0.4) |
25,056 (16.4) |
126,962 (83.2) |
727 (0.9) |
11,704 (13.9) |
71,853 (85.3) |
| High HDI |
2020 |
6300 (1.4) |
166,974 (36.2) |
287,885 (62.4) |
2729 (0.9) |
116,130 (37.4) |
192,020 (61.8) |
3571 (2.4) |
50,844 (33.8) |
95,865 (63.8) |
|
2030 |
5390 (1.0) |
171,912 (31.0) |
377,718 (68.1) |
2150 (0.6) |
119,773 (32.4) |
248,285 (67.1) |
3240 (1.8) |
52,139 (28.2) |
129,433 (70.0) |
|
2040 |
4967 (0.8) |
150,647 (24.1) |
470,678 (75.2) |
1873 (0.4) |
105,549 (25.2) |
311,766 (74.4) |
3094 (1.5) |
45,098 (21.8) |
158,912 (76.7) |
| Medium HDI |
2020 |
5919 (5.3) |
54,897 (49.4) |
50,334 (45.3) |
2947 (4.1) |
36,024 (50.4) |
32,511 (45.5) |
2972 (7.5) |
18,873 (47.6) |
17,823 (44.9) |
|
2030 |
6541 (4.8) |
61,395 (45.3) |
67,585 (49.9) |
2732 (3.2) |
39,835 (46.8) |
42,505 (50.0) |
3809 (7.6) |
21,560 (42.7) |
25,080 (49.7) |
|
2040 |
7040 (4.3) |
67,170 (41.3) |
88,548 (54.4) |
2410 (2.4) |
43,332 (43.2) |
54,585 (54.4) |
4630 (7.4) |
23,838 (38.2) |
33,963 (54.4) |
| Low HDI |
2020 |
1672 (6.8) |
11,783 (48.0) |
11,092 (45.2) |
929 (6.7) |
6767 (49.1) |
6094 (44.2) |
743 (6.9) |
5016 (46.6) |
4998 (46.5) |
|
2030 |
824 (2.5) |
18,281 (56.3) |
13,338 (41.1) |
448 (2.2) |
12,438 (61.2) |
7424 (36.6) |
375 (3.1) |
5843 (48.2) |
5914 (48.7) |
|
2040 |
391 (0.8) |
30,719 (64.5) |
16,485 (34.6) |
208 (0.6) |
22,717 (70.4) |
9342 (29.0) |
183 (1.2) |
8001 (52.2) |
7142 (46.6) |
| Geographical regions |
| Northern America |
2020 |
389 (2.9) |
3946 (29.5) |
9056 (67.6) |
199 (2.5) |
2474 (30.6) |
5417 (67.0) |
190 (3.6) |
1472 (27.8) |
3639 (68.6) |
|
2030 |
427 (2.7) |
3868 (24.3) |
11,590 (73.0) |
213 (2.2) |
2377 (24.7) |
7047 (73.1) |
214 (3.4) |
1491 (23.9) |
4543 (72.7) |
|
2040 |
447 (2.5) |
4060 (22.4) |
13,634 (75.2) |
216 (2.0) |
2454 (22.4) |
8303 (75.7) |
231 (3.2) |
1607 (22.4) |
5331 (74.4) |
| Eastern Asia |
2020 |
3912 (0.9) |
143,989 (33.3) |
284,424 (65.8) |
1628 (0.6) |
101,556 (34.6) |
190,376 (64.9) |
2284 (1.6) |
42,433 (30.6) |
94,048 (67.8) |
|
2030 |
2636 (0.4) |
158,140 (26.7) |
431,738 (72.9) |
1021 (0.3) |
112,201 (28.0) |
287,609 (71.8) |
1615 (0.8) |
45,939 (24.0) |
144,129 (75.2) |
|
2040 |
2001 (0.3) |
138,043 (18.2) |
617,544 (81.5) |
782 (0.2) |
98,858 (19.1) |
417,842 (80.7) |
1219 (0.5) |
39,185 (16.3) |
199,703 (83.2) |
| Eastern Africa |
2020 |
887 (10.2) |
4120 (47.3) |
3695 (42.5) |
511 (12.0) |
1958 (46.0) |
1786 (42.0) |
376 (8.5) |
2162 (48.6) |
1909 (42.9) |
|
2030 |
431 (3.8) |
6367 (56.7) |
4428 (39.4) |
243 (4.0) |
3729 (61.0) |
2145 (35.1) |
189 (3.7) |
2638 (51.6) |
2283 (44.7) |
|
2040 |
203 (1.2) |
10,836 (64.8) |
5679 (34.0) |
111 (1.1) |
7037 (70.5) |
2831 (28.4) |
92 (1.4) |
3799 (56.4) |
2848 (42.3) |
| Middle Africa |
2020 |
163 (5.5) |
1338 (45.0) |
1471 (49.5) |
80 (5.2) |
772 (50.3) |
683 (44.5) |
83 (5.8) |
566 (39.4) |
788 (54.8) |
|
2030 |
175 (4.3) |
1861 (45.4) |
2062 (50.3) |
83 (3.5) |
1236 (52.8) |
1022 (43.7) |
92 (5.2) |
625 (35.6) |
1040 (59.2) |
|
2040 |
186 (3.2) |
2678 (46.0) |
2957 (50.8) |
85 (2.3) |
1994 (54.9) |
1551 (42.7) |
101 (4.6) |
683 (31.2) |
1406 (64.2) |
| Northern Africa |
2020 |
543 (7.0) |
3371 (43.7) |
3799 (49.3) |
272 (6.1) |
1973 (44.0) |
2235 (49.9) |
271 (8.4) |
1398 (43.2) |
1564 (48.4) |
|
2030 |
462 (4.6) |
4352 (43.6) |
5174 (51.8) |
227 (3.6) |
2984 (46.9) |
3153 (49.5) |
234 (6.5) |
1368 (37.8) |
2021 (55.8) |
|
2040 |
407 (2.9) |
5747 (41.3) |
7753 (55.7) |
194 (2.0) |
4416 (46.1) |
4964 (51.9) |
213 (4.9) |
1331 (30.7) |
2789 (64.4) |
| Southern Africa |
2020 |
78 (5.0) |
735 (46.7) |
762 (48.4) |
41 (4.3) |
486 (50.9) |
427 (44.8) |
37 (6.0) |
249 (40.1) |
335 (53.9) |
|
2030 |
62 (3.0) |
928 (45.3) |
1059 (51.7) |
32 (2.4) |
695 (53.2) |
580 (44.4) |
30 (4.1) |
233 (31.4) |
479 (64.5) |
|
2040 |
47 (1.7) |
1224 (44.4) |
1483 (53.8) |
23 (1.2) |
1002 (52.0) |
903 (46.8) |
24 (2.9) |
222 (26.9) |
580 (70.2) |
| Western Africa |
2020 |
429 (6.2) |
3563 (51.2) |
2964 (42.6) |
221 (5.7) |
2027 (52.5) |
1612 (41.8) |
208 (6.7) |
1536 (49.6) |
1352 (43.7) |
|
2030 |
436 (4.6) |
4760 (50.0) |
4330 (45.5) |
219 (3.7) |
3192 (54.2) |
2478 (42.1) |
217 (6.0) |
1568 (43.1) |
1852 (50.9) |
|
2040 |
446 (3.3) |
6830 (50.8) |
6174 (45.9) |
218 (2.4) |
5172 (56.9) |
3700 (40.7) |
228 (5.2) |
1657 (38.0) |
2474 (56.8) |
| Caribbean |
2020 |
86 (2.6) |
1078 (32.7) |
2133 (64.7) |
45 (2.2) |
708 (34.9) |
1278 (62.9) |
41 (3.2) |
370 (29.2) |
855 (67.5) |
|
2030 |
93 (2.5) |
1177 (31.4) |
2479 (66.1) |
47 (2.1) |
768 (33.9) |
1450 (64.0) |
46 (3.1) |
408 (27.5) |
1029 (69.4) |
|
2040 |
92 (2.1) |
1197 (27.9) |
3002 (70.0) |
44 (1.7) |
776 (30.3) |
1741 (68.0) |
47 (2.7) |
421 (24.4) |
1261 (72.9) |
| Central America |
2020 |
536 (4.9) |
3798 (35.1) |
6499 (60.0) |
257 (4.3) |
2113 (35.1) |
3649 (60.6) |
279 (5.8) |
1685 (35.0) |
2850 (59.2) |
|
2030 |
413 (3.5) |
4052 (33.9) |
7496 (62.7) |
167 (2.6) |
2176 (33.9) |
4078 (63.5) |
246 (4.4) |
1876 (33.9) |
3417 (61.7) |
|
2040 |
304 (2.3) |
4145 (30.9) |
8985 (66.9) |
101 (1.4) |
2153 (30.9) |
4713 (67.7) |
204 (3.1) |
1992 (30.8) |
4272 (66.0) |
| South-Eastern Asia |
2020 |
982 (3.0) |
14,841 (45.2) |
16,991 (51.8) |
470 (2.3) |
9665 (48.1) |
9971 (49.6) |
512 (4.0) |
5176 (40.7) |
7020 (55.2) |
|
2030 |
845 (2.2) |
14,586 (38.8) |
22,191 (59.0) |
357 (1.6) |
9686 (43.4) |
12,299 (55.1) |
489 (3.2) |
4900 (32.1) |
9891 (64.7) |
|
2040 |
714 (1.7) |
13,853 (33.2) |
27,166 (65.1) |
259 (1.1) |
9470 (39.8) |
14,044 (59.1) |
454 (2.5) |
4383 (24.4) |
13,121 (73.1) |
| South-Central Asia |
2020 |
4888 (5.5) |
43,885 (49.0) |
40,822 (45.6) |
2465 (4.1) |
29,411 (49.2) |
27,956 (46.7) |
2423 (8.1) |
14,474 (48.6) |
12,866 (43.2) |
|
2030 |
5863 (5.0) |
54,191 (45.9) |
57,892 (49.1) |
2414 (3.2) |
35,081 (46.4) |
38,187 (50.5) |
3449 (8.2) |
19,110 (45.2) |
19,705 (46.6) |
|
2040 |
6818 (4.5) |
66,602 (43.7) |
78,822 (51.8) |
2231 (2.3) |
41,980 (44.2) |
50,780 (53.5) |
4587 (8.0) |
24,621 (43.0) |
28,042 (49.0) |
| Western Asia |
2020 |
595 (3.4) |
7046 (39.8) |
10,060 (56.8) |
252 (2.2) |
4680 (41.7) |
6292 (56.1) |
343 (5.3) |
2366 (36.5) |
3768 (58.2) |
|
2030 |
686 (3.3) |
9975 (47.7) |
10,240 (49.0) |
266 (1.9) |
6819 (49.6) |
6661 (48.5) |
419 (5.9) |
3156 (44.1) |
3579 (50.0) |
|
2040 |
802 (3.2) |
12,320 (48.5) |
12,287 (48.4) |
292 (1.7) |
8454 (49.2) |
8426 (49.1) |
510 (6.2) |
3866 (46.9) |
3861 (46.9) |
| Eastern Europe |
2020 |
724 (1.4) |
16,402 (32.8) |
32,892 (65.8) |
314 (1.0) |
11,441 (37.6) |
18,688 (61.4) |
410 (2.1) |
4961 (25.3) |
14,204 (72.6) |
|
2030 |
486 (1.0) |
14,043 (28.5) |
34,753 (70.5) |
202 (0.7) |
9867 (32.5) |
20,292 (66.8) |
284 (1.5) |
4176 (22.1) |
14,461 (76.4) |
|
2040 |
416 (0.9) |
13,562 (27.7) |
35,004 (71.5) |
174 (0.6) |
9678 (31.6) |
20,800 (67.9) |
242 (1.3) |
3884 (21.2) |
14,203 (77.5) |
| Northern Europe |
2020 |
98 (1.3) |
1501 (19.4) |
6149 (79.4) |
35 (0.7) |
986 (20.5) |
3796 (78.8) |
63 (2.1) |
515 (17.6) |
2353 (80.3) |
|
2030 |
89 (1.1) |
1327 (16.5) |
6603 (82.3) |
37 (0.7) |
853 (16.9) |
4164 (82.4) |
52 (1.7) |
474 (16.0) |
2439 (82.3) |
|
2040 |
80 (1.0) |
1159 (14.4) |
6822 (84.6) |
37 (0.7) |
729 (14.2) |
4355 (85.0) |
43 (1.5) |
430 (14.6) |
2467 (83.9) |
| Southern Europe |
2020 |
167 (0.8) |
4267 (20.0) |
16,889 (79.2) |
80 (0.6) |
2832 (21.7) |
10,152 (77.7) |
87 (1.1) |
1435 (17.4) |
6737 (81.6) |
|
2030 |
126 (0.6) |
3866 (17.7) |
17,834 (81.7) |
67 (0.5) |
2485 (18.5) |
10,916 (81.1) |
59 (0.7) |
1381 (16.5) |
6918 (82.8) |
|
2040 |
104 (0.5) |
3044 (13.4) |
19,504 (86.1) |
60 (0.4) |
1887 (13.5) |
12,053 (86.1) |
44 (0.5) |
1157 (13.4) |
7451 (86.1) |
| Western Europe |
2020 |
197 (1.1) |
3923 (22.1) |
13,629 (76.8) |
90 (0.8) |
2724 (24.7) |
8220 (74.5) |
107 (1.6) |
1199 (17.9) |
5409 (80.6) |
|
2030 |
151 (0.8) |
3567 (19.3) |
14,740 (79.9) |
58 (0.5) |
2462 (21.2) |
9108 (78.3) |
93 (1.4) |
1105 (16.2) |
5632 (82.5) |
|
2040 |
115 (0.6) |
3250 (17.2) |
15,573 (82.2) |
35 (0.3) |
2223 (18.6) |
9694 (81.1) |
79 (1.1) |
1027 (14.7) |
5879 (84.2) |
| Australia/New Zealand |
2020 |
28 (2.1) |
316 (23.3) |
1011 (74.6) |
12 (1.4) |
200 (23.8) |
627 (74.7) |
16 (3.1) |
116 (22.5) |
384 (74.4) |
|
|
|
|
|
|
|
|
|
|
|
|
2030 |
26 (1.6) |
334 (20.0) |
1310 (78.4) |
12 (1.2) |
215 (20.8) |
810 (78.1) |
14 (2.2) |
119 (18.7) |
501 (79.0) |
|
2040 |
21 (1.1) |
361 (18.6) |
1556 (80.3) |
10 (0.9) |
238 (20.0) |
942 (79.1) |
11 (1.5) |
122 (16.4) |
614 (82.1) |
| South America |
2020 |
1262 (3.2) |
12,754 (32.6) |
25,149 (64.2) |
561 (2.3) |
8196 (33.5) |
15,692 (64.2) |
701 (4.8) |
4558 (31.0) |
9457 (64.3) |
|
2030 |
1421 (3.4) |
13,179 (31.8) |
26,792 (64.7) |
527 (2.0) |
8501 (32.5) |
17,097 (65.4) |
894 (5.9) |
4678 (30.6) |
9696 (63.5) |
|
2040 |
1545 (3.5) |
13,273 (29.9) |
29,595 (66.6) |
467 (1.6) |
8596 (30.3) |
19,329 (68.1) |
1078 (6.7) |
4676 (29.2) |
10,266 (64.1) |
| Melanesia/Micronesia/Polynesia |
2020 |
17 (3.5) |
198 (41.0) |
268 (55.5) |
8 (2.8) |
120 (41.7) |
160 (55.6) |
9 (4.6) |
78 (40.0) |
108 (55.4) |
|
|
|
|
|
|
|
|
|
|
|
|
2030 |
19 (2.9) |
269 (39.9) |
386 (57.2) |
10 (2.4) |
167 (40.9) |
231 (56.8) |
10 (3.6) |
103 (38.4) |
155 (58.0) |
|
2040 |
19 (2.1) |
330 (37.2) |
540 (60.7) |
10 (1.9) |
206 (39.9) |
300 (58.1) |
9 (2.4) |
124 (33.3) |
239 (64.3) |
Data are shown as n (%). HDI: Human development.
Variation trend in age
The number of new cases in the young group was 26.19 thousand by 2020, decreasing to 22.74 thousand by 2030 and to 19.84 thousand by 2040. The number of new cases in the middle-aged group was 0.42 million in 2020, increasing to 0.47 million in 2030 and to 0.49 million in 2040, and in the elderly group, it was 0.64 million in 2020, increasing to 0.86 million in 2030 and to 1.12 million in 2040. The number of deaths in the young group was 16.03 thousand in 2020, decreasing to 13.89 thousand by 2030 and to 12.15 thousand by 2040; the number of deaths in the middle-aged group in 2020 was 0.27 million, increasing to 0.30 million in 2030 and to 0.32 million in 2040; the number of deaths in the elderly group was 0.48 million in 2020, increasing to 0.65 million in 2030 and to 0.85 million in 2040 [Tables 1 and 2].
From 2020 to 2040, the proportion of incident cases and deaths in the three groups will change. The proportion of the young group in global newly diagnosed cases and deaths gradually will decline from 2.4% and 2.1% in 2020 to 1.2% and 1.0% in 2040, respectively, and that of the middle-aged group will gradually decline from 38.7% and 35.4% in 2020 to 30.2% and 27.0% in 2040, respectively, while in the elderly group, they will increased from 58.9% and 62.6% in 2020 to 68.6% and 72.0% in 2040, respectively.
Variation in trends by sex
The newly diagnosed cases and deaths in males will increase from 0.72 million and 0.50 million in 2020 to 0.89 million and 0.63 million in 2030, and to 1.09 million and 0.78 million in 2040, respectively. The male-to-female ratios of new cases and deaths will be 1.95, 1.96 in 2020, 2.01 and 1.89 in 2030, 1.91, 1.95 in 2040, respectively. The ratios will also vary with age group. A significant difference was found in the middle-aged group, in which the male-to-female ratio of new cases will decrease from 2.16 in 2020 to 2.15 in 2040 and that of deaths will decrease from 2.12 in 2020 to 2.11 in 2040. This is followed by the elderly group, in which the male-to-female ratio of new cases will increase from 1.88 in 2020 to 1.99 in 2040, and the ratio of deaths will increase from 1.82 in 2020 to 1.92 in 2040. The lowest male-to-female ratio will be observed in the young group, in which the ratio for new cases will decrease from 0.92 to 0.82, and that for deaths will decrease from 0.89 to 0.80.
Variation trend in regions
In the next 20 years, the number of newly diagnosed cases and deaths in almost all regions of the world will continue to increase. East Asia is a high HDI region that is expected to be one of the hotspots of incidence and mortality for GC. East Asia alone had 59.85% of the global new cases and 56.23% of deaths in 2020, and by 2040, these will increase to 66.93% and 64.37%, respectively. Overall, the high HDI regions accounted for 53.89% of the global new cases and 59.98% of deaths in 2020. From 2020 to 2040, Middle Africa will have the largest increase in incident cases and deaths (95.58% and 95.86%), while Eastern Europe will have the only decrease in incident cases and deaths (–4.60% and –2.07%).
It is worth noting that the composition of new cases and deaths in each HDI region will vary by age group over the next 20 years. In very high HDI regions, the proportion of the elderly group will be over 70% and that of the middle-aged group will be approximately 20%. In high HDI regions, the proportion of new cases and deaths in the middle-aged group will decrease from 43.20% and 36.21% in 2020 to 30.16% and 24.05% in 2040, respectively. The proportion of the elderly group will increase from 54.86% and 62.43% in 2020 to 68.65% and 75.15% in 2040, respectively. The proportion of the young group will increase from 1.94% and 1.37% in 2020 to 1.19% and 0.79% in 2040, respectively. The proportion of the elderly group will be similar in the medium- and low-HDI regions. The proportion of new cases and deaths in the young group will be lower than 10% in all regions [Tables 1 and 2, Figures 2 and 3].
Figure 2: Number of new cases in (A) young, middle-aged and elderly groups, (B) males and females in the three age-groups, and (C–F) regions with a very high, high, medium, and low HDI from 2020 to 2040.
Figure 3: Number of deaths in (A) young, middle-aged and elderly groups, (B) males and females in the three age-groups, and (C–F) regions with a very high, high, medium, and low HDI from 2020 to 2040.
Comprehensive influence of population growth, ageing structure change, and risk reduction on the prevalent trends of GC
The number of new GC cancer incident cases will increase by approximately 23.90% between 2020 and 2030, with age-specific incidence rates (or changes that can be explained by changes due to risk) contributing a 6.99% decrease, age structures contributing a 21.26% increase, and population growth contributing a 9.64% increase to the overall increase. The number of new GC cancer incident cases will increase by approximately 49.76% between 2020 and 2040, with age structures contributing 46.87% to this change [Figure 4A, Supplemental Table 7, https://links.lww.com/CM9/B461]. The number of GC cancer deaths will increase by approximately 25.11% between 2020 and 2030, with changing age-specific mortality rates contributing a 6.93% decrease and changing age structures contributing a 32.04% increase to the overall increase. However, the number of GC cancer deaths will increase by approximately 53.07% between 2020 and 2040, and changing age structures will contribute a 50.16% increase to this [Figure 4B, Supplemental Table 8, https://links.lww.com/CM9/B461]. The detailed results are listed in [Supplemental Figures 1–3, https://links.lww.com/CM9/B461].
Figure 4: The overall increasing trend of the new GC cancer incident cases (A) and deaths (B) from 2020 to 2040, with the contributing factors including changing age-specific incidence rates, changing age structures and population growth.
Discussion
We present a comprehensive analysis of the predicted global burden of GC from 2020 to 2040, including not only the effect of demographic transition on the incidence of cases and deaths but also the trend of incidence and mortality in the next 20 years. Furthermore, we also estimated the influence of age structure changes on the burden of GC. We predicted a 49.76% increase in the number new cases and a 53.07% increase in the number of deaths. We assumed that the global population will continue to grow by 17.9% and that the incidence rate of GC will continue to decrease, with an APC of –2.13% for males and –1.53% for females in the next two decades.
Several key observations can be derived from our study. First, unprecedented ageing and population growth will offset the decline in incidence and mortality rate, leading to noteworthy increases in the number of newly diagnosed cases and deaths, which will profoundly affect the future burden of GC. Second, a large proportion of the increase in the incidence of cases and deaths will be caused by population ageing, while the increase in population growth will account for a much lower proportion of the increase. Third, the age demographics of incidence and death will also change, especially in high HDI regions that experience severe demographic transitions. They will experience a progressive increase in the proportion of the elderly population accounting for both incident cases and deaths. In the future, more targeted prevention strategies need to be formulated.
There are two key elements determining the number of newly diagnosed cases and deaths—demographic changes and incidence/mortality rates.[16] In the past several decades, steady declines in the incidence and mortality rates of GC have been observed consistently across the world. Furthermore, the mortality rate has decreased more rapidly than the incidence rate.[17-20] We predicted the variation in incidence and mortality rates by analyzing The CI5 Time Trends data, which were similar to the results of previous studies, and we obtained more detailed trends for each age group and region. The worldwide decline in incidence and mortality is in fact an “unplanned triumph” attributable to the decrease in risk factors for GC in the absence of active primary prevention and population-based screening.[7]Helicobacter pylori infection is the most important cause of gastric cancer and induces inflammation-associated oncogenesis. Environmental factors also play an important causal role in the occurrence of gastric cancer. Low consumption of fruits and vegetables and high intake of salts, nitrates, and pickled foods, as well as smoking, have been associated with an increased risk of gastric cancer.[21] Improvements in socioeconomic factors have led to improved food preservation practices and medical treatment, as well as improved living conditions. Intervention studies indicated that the eradication of Helicobacter pylori has been shown to reduce the risk of early GC by nearly 50%,[22] while the adoption of a healthy lifestyle with a healthy diet, no smoking or alcohol use, a normal body mass index, and regular physical activity resulted in a 10% reduction in gastric cancer risk.[23]
Countries have entered a period of demographic transition. The period between 2020 and 2040 is will be a later stage of this transition,[1] and the ageing of the population will be aggravated. The world's demographics are expected to diverge sharply in the coming decades, with the population of developed countries stagnating or possibly declining, while the population of developing countries continue to grow rapidly. Notably, the level of ageing is positively correlated with the HDI of a country. By 2040, the majority of high HDI countries will enter the superaged phase, while medium HDI countries will enter the ageing phase. Very high and high HDI countries will experience 20.39% and 8.89% decreases in the young population and 41.45% and 104.0% increases in the elderly population, respectively. GC is considered to be an age-related disease, and the median age at diagnosis is 70 years.[4] An ageing demographic overpowers risk factor improvement and contributes to an increase in GC. This point of view is also supported by a study predicting the global gastric cancer burden through 2070.[16]
Our projections show that the age structure of GC incident cases and deaths will also change with the demographic transition in the next 20 years and will be mainly concentrated in high HDI regions. The proportions of elderly and middle-aged populations will be comparable in low and medium HDI regions, which will be maintained at 70% to 80% and 20% in the very high HDI regions, respectively. In the high HDI regions, the proportion of the elderly and middle-aged population will gradually increase from 60% and 30% in 2020 to 70% and 20% in 2040, respectively. In other words, with the increase in HDI levels, the proportion of elderly patients with GC will continue to increase.
Geographic variations in the incidence and mortality rates will be observed in GC. The GLOBOCAN2020 data indicated that the highest ASIR and ASMR were observed in high HDI regions. The reason for this is that most of the hot-spot countries for GC are high HDI regions, such as East Asia, Eastern Europe, and South America, in which account for 54.78% and 64.18% of the new cases and deaths globally, respectively. To date, there is no national screening program in these high-risk countries. Therefore, tailored local strategies are needed based on each country's risk factor profile and level of socioeconomic development. National programs aimed at reducing mortality rates and improving survival rates have been implemented in Japan and South Korea, two high-risk countries from East Asia. Hence, the screening and eradication of Helicobacter pylori can be effective in preventing gastric cancer in high-risk developed countries. For developing regions at high risk, there is an urgent need to increase accessibility to high-level medical technologies, availability of medical resources and early detection methods for GC. Our projections suggest that a further decrease in the absolute number of new cases and deaths could be possible if the rates in East Asia are further reduced through effective measures.[18]
In addition, we found that the male-to-female ratio of new cases and deaths among the three age groups differed, and the most significant difference in the male-to-female ratio was observed in the middle-aged group, followed by the elderly group and the young group. The main reason for this is as follows: first, the incidence and mortality rate increase significantly after the age of 40; second, males are more susceptible to GC since smoking and alcohol consumption are more common among males; third, the proportion males decreases in the elderly population over 65 years of age. A study on the sex difference based on GBD data showed that the most significant difference was in the group aged 65 to 69 years.[24] Therefore, further analyzing the age-specific patterns of the sex difference in incidence may provide aetiological clues on risk factors with age-dependent associations with gastric cancer risk.[25]
This study's strengths are that we analysed both demographic changes and trends in incidence and mortality rates in the future 20 years to project variations in geography, social economy, sex and age among gastric cancer patients worldwide. However, there were also several limitations. First, our estimates of the incidence and mortality trends were based on two databases, including the GLOBOCAN2020 database and CI5 database. Second, gastric cancer can be classified into cardiac and noncardiac cancers aetiologically and anatomically, but in our study, they were treated as one entity. Third, in our research, we only considered the impact of population growth and age structure changes on the incidence and mortality rate of GC, but we did not consider the impact of economic and medical development, improvement of people's health awareness and lifestyle changes on the occurrence and development of GC.
In conclusion, our study indicates that population growth and ageing offset the decline in the GC incidence and mortality rates, resulting in a substantial increase in newly diagnosed cases and deaths largely resulting from the ageing of populations. As the population ages, the age of the population impacted GC incidence and death will increase. Additionally, the disease burden of GC will still be concentrated in East Asia and high HDI regions, which are undergoing profound demographic changes. These high-risk regions need more targeted prevention and screening strategies in the future.
Acknowledgements
The views expressed are those of the authors only and do not represent any official position of the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing) or Peking University Cancer Hospital & Institute.
Funding
The work was supported by a grant from the Summit Talent Plan of Beijing Hospitals Authority (No. DFL20181103).
Conflicts of interest
None.
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