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Cancer Research and Treatment > Volume 53(2); 2021 > Article
Jung, Won, Hong, Kong, Im, and Seo: Prediction of Cancer Incidence and Mortality in Korea, 2021

Abstract

Purpose

This study aimed to report the projected cancer incidence and mortality for the year 2021 to estimate Korea’s current cancer burden.

Materials and Methods

Cancer incidence data from 1999 to 2018 were obtained from the Korea National Cancer Incidence Database, and cancer mortality data from 1993 to 2019 were acquired from Statistics Korea. Cancer incidence and mortality were projected by fitting a linear regression model to observed age-specific cancer rates against their respective years and then by multiplying the projected age-specific rates by the anticipated age-specific population for 2021. A joinpoint regression model was used to determine the year in which the linear trend changed significantly; we only used the data of the latest trend.

Results

In total, 259,999 new cancer cases and 81,567 cancer deaths are expected to occur in Korea in 2021. The most common cancer site is expected to be the lung, followed by the thyroid, colon and rectum, breast, and stomach. These five cancers are expected to represent half of the overall burden of cancer in Korea. The most common type of cancer leading to death is expected to be lung cancer, followed by liver, colorectal, pancreatic, and stomach cancers.

Conclusion

The incidence rates for all types of cancer in Korea are estimated to gradually decrease. These up-to-date estimates of the cancer burden in Korea could be an important resource for planning and evaluating cancer-control programs.

Introduction

As the leading cause of death in Korea [1], cancer has been a major public health concern in the country since 1983. More than 230,000 patients were newly diagnosed with cancer in Korea, and one-fourth of deaths were due to cancer in 2017 [2]. Although the cancer registration system in Korea is highly efficient and can provide nationwide cancer statistics within a relatively short period, a lag time of at least 2 years is required to collect and analyze data for a specific year. For planning and implementing comprehensive cancer-control programs, it is important to assess the number of new cases and deaths that are expected to occur during the current year. In this study, we report the projected cancer incidence and mortality for the year 2021 based on data from the 1990s to 2018.

Materials and Methods

The Korean Ministry of Health and Welfare initiated a nationwide, hospital-based cancer registry, known as the Korea Central Cancer Registry (KCCR), in 1980. The history, objectives, and activities of the KCCR have been documented in detail elsewhere [3]. Cancer incidence data from 1999 to 2018 were obtained from the Korea National Cancer Incidence Database (KNCI DB). Cancer cases were classified according to the International Classification of Diseases for Oncology, 3rd edition [4] and converted according to the International Classification of Diseases, 10th edition (ICD-10) [5]. Mortality data from 1993 to 2019 were acquired from Statistics Korea [1]. The cause of death was coded and classified according to the ICD-10 [5].
The cancer sites included in this study were (1) all cancer sites combined and (2) the 24 cancer sites as follows: lips, oral cavity, and pharynx (C00-C14), esophagus (C15), stomach (C16), colon and rectum (C18-C20), liver (C22), gallbladder etc. (C23-C24), pancreas (C25), larynx (C32), lung (C33-C34), breast (C50), cervix uteri (C53), corpus uteri (C54), ovary (C56), prostate (C61), testis (C62), kidney (C64), bladder (C67), brain and central nervous system (C70-C72), thyroid (C73), Hodgkin lymphoma (C81), non-Hodgkin lymphoma (C82-C86, C96), multiple myeloma (C90), leukemia (C91-C95), and other and ill-defined sites (remainder of C00-C96).
The population data were obtained from the resident registration population data, reported by Statistics Korea. Data of the mid-year population (July 1 of the respective year) were used as the denominator to obtain the annual incidence and mortality rates. However, for the year 2021, we used the population data on December 31, 2020, as the mid-2021 resident registration population data were not yet available at the time of the analysis.
Linear regression models [6] were used to assess time trends and create projections. We first performed a joinpoint regression analysis on the data available to detect the year when significant changes occurred in cancer trends according to sex and cancer site. A joinpoint regression describes changes in data trends by connecting several different line segments on a log scale at “joinpoints.” This analysis was performed using Joinpoint software (version 4.7.0.0; http://surveillance.cancer.gov/joinpoint) from the Surveillance Research Program of the US National Cancer Institute [7]. For the analysis, we arranged to have at least four data points between consecutive joinpoints. Secondly, to predict age-specific cancer rates, a linear regression model was fitted to age-specific rates by 5-year age groups against their respective years, based on the observed cancer incidence data of the latest trends. Finally, we multiplied the projected age-specific rates by the age-specific population to get the projected number of cancer cases and deaths for the year 2021.
We summarized the results using crude rates (CRs) and age-standardized rates (ASRs) of cancer incidence and mortality. ASRs were standardized using the world standard population [8] and expressed per 100,000 persons.

Results

1. Incidence

In total, 259,999 new cancer cases are expected to occur in 2021 (Table 1, Fig. 1); more men (n=135,577) than women (n=124,422) are expected to be affected.
The projected CRs per 100,000 for all of the sites combined in 2021 are 524.7 cases and 478.8 cases for men and women, respectively (Table 2). The projected ASRs per 100,000 for all of the sites combined are 280.0 cases and 265.2 cases for men and women, respectively. In men, the five leading primary sites of cancer are expected to be the lung (CR, 82.1; ASR, 39.7), stomach (CR, 69.3; ASR, 35.8), colon and rectum (CR, 66.2; ASR, 34.4), prostate (CR, 64.8; ASR, 31.5), and liver (CR, 42.5; ASR, 22.0), accounting for 61.9% of all new cancer cases in 2021. In women, the five leading primary sites are expected to be the breast (CR, 103.2; ASR, 63.6), thyroid (CR, 89.3; ASR, 66.3), colon and rectum (CR, 42.6; ASR, 17.7), lung (CR, 42.1; ASR, 18.1), and stomach (CR, 34.1; ASR, 15.7), accounting for 65.0% of all new cancer cases in 2021 (Fig. 1).
The five most common cancer sites expected in 2021 according to sex and age group are shown in Table 3. Leukemia and thyroid cancer are expected to be the most common forms of cancer in both sexes for those aged 0–14 years and 15–34 years, respectively. Stomach cancer is predicted to be the most prevalent cancer in men aged 35–64 years, while lung cancer is expected to be more frequent in men aged 65 years and above. Breast cancer is predicted to be the most common cancer in women aged 35–64 years, whereas colorectal cancer is expected to be the most common form in women aged 65 years and above. According to the projection, the incidences of stomach, lung, liver, colorectal, and prostate cancers will increase gradually with age for men (Fig. 2A). In women, the age-specific incidence rates for stomach, colorectal, liver, lung, and cervical cancers denote an increasing trend with age; however, the incidences of breast and thyroid cancers in women are expected to level off after the age of 45 and 50 years, respectively (Fig. 2B).

2. Mortality

It is estimated that 81,567 cancer deaths will occur in Korea during 2021 (Table 1, Fig. 1). The projected CRs per 100,000 for all of the sites combined in 2021 for men and women are 192.1 cases and 122.9 cases, respectively, whereas the projected ASRs per 100,000 for all sites combined for men and women are expected to be 92.6 cases and 45.5 cases, respectively (Table 4). The predicted five leading cancer sites causing mortality in men are the lung (CR, 52.7; ASR, 24.4), liver (CR, 27.2; ASR, 13.5), colon and rectum (CR, 19.0; ASR, 9.2), stomach (CR, 14.9; ASR, 7.2), and pancreas (CR, 14.1; ASR, 6.9). During the same period, lung cancer (CR, 18.4; ASR, 6.2) is projected to be the leading cause of cancer death in women, followed by colon and rectal (CR, 15.2; ASR, 4.9), pancreatic (CR, 13.1; ASR, 4.6), liver (CR, 10.9; ASR, 3.6), and breast (CR, 10.9; ASR, 5.7) cancers.
The predicted age-specific mortality rates of the leading causes of cancer-associated death in men and women in 2021 are shown in detail in Fig. 3. According to age, Korean men and women aged at least 60 years are expected to have the highest mortality rates due to lung cancer.

Conclusion

A total of 259,999 new cancer cases and 81,567 cancer deaths are expected to occur in Korea during 2021. Lung cancer is predicted to be the most common type of cancer among men, followed by stomach, colorectal, prostate, and liver cancers. Lung, liver, colorectal, stomach, and pancreatic cancers are expected to be the most common causes of cancer deaths among men. In women, the five leading primary cancer sites are expected to be the breast, thyroid, colon and rectum, lung, and stomach, while lung, colorectal, pancreatic, liver, and breast cancers are projected to be the most common causes of cancer deaths.
Cancer is currently one of the foremost public health concerns in Korea. Although cancer incidence rates are anticipated to slightly decrease, the burden of most types of cancers will continue to grow with the increasing age of the population. The current projections of cancer incidence and mortality for 2021 represent an important resource for planning and evaluating cancer-control programs. As the estimates in this study are model-based, these results should be interpreted with caution.

Notes

Author Contributions

Conceived and designed the analysis: Won YJ.

Contributed data or analysis tools: Jung KW, Won YJ, Kong HJ.

Performed the analysis: Jung KW.

Wrote the paper: Jung KW, Won YJ.

Interpretation and review: Hong S.

Review and comment: Im JS, Seo HG.

Conflicts of Interest

Conflict of interest relevant to this article was not reported.

Acknowledgments

The authors would like to thank the tumor registrars (health information managers) of the KCCR-affiliated hospitals and non-KCCR-affiliated hospitals for the assistance with data collection, abstraction, and coding. Additionally, we acknowledge the cooperation of the National Health Insurance Service and Statistics Korea for their support with the data.
This work was supported by the National Cancer Center research grant (No. 1910131).

Fig. 1
The 10 leading types of estimated new cancer cases and deaths by sex in 2021. (A) Estimated new cases. (B) Estimated deaths.
crt-2021-290f1.jpg
Fig. 2
Projected age-specific incidences of major cancers during 2021 in Korea. (A) Men. (B) Women.
crt-2021-290f2.jpg
Fig. 3
Projected age-specific mortality rates of major cancers during 2021 in Korea. (A) Men. (B). Women.
crt-2021-290f3.jpg
Table 1
Estimated new cancer cases and deaths by sex during 2021 in Korea
Site Estimated new cases Estimated deaths


Both sexes Men Women Both sexes Men Women
All sites 259,999 135,577 124,422 81,567 49,630 31,937

Lip, oral cavity, and pharynx 4,077 2,926 1,151 1,257 913 344

Esophagus 2,622 2,379 243 1,260 1,125 135

Stomach 26,768 17,899 8,869 5,808 3,842 1,966

Colon and rectum 28,177 17,110 11,067 8,865 4,907 3,958

Livera) 14,707 10,991 3,716 9,856 7,033 2,823

Gallbladderb) 8,338 4,460 3,878 5,387 2,890 2,497

Pancreas 8,812 4,569 4,243 7,031 3,634 3,397

Larynx 1,066 1,005 61 250 231 19

Lungc) 32,149 21,206 10,943 18,379 13,611 4,768

Breast 26,926 102 26,824 2,840 18 2,822

Cervix uteri 3,105 - 3,105 794 - 794

Corpus uteri 3,467 - 3,467 403 - 403

Ovary 3,080 - 3,080 1,344 - 1,344

Prostate 16,749 16,749 - 2,140 2,140 -

Testis 326 326 - 18 18 -

Kidney 6,244 4,290 1,954 1,174 814 360

Bladder 5,067 4,020 1,047 1,564 1,157 407

Brain and CNS 2,170 1,165 1,005 1,387 719 668

Thyroid 31,144 7,938 23,206 344 98 246

Hodgkin lymphoma 350 216 134 64 39 25

Non-Hodgkin lymphoma 5,791 3,333 2,458 2,247 1,288 959

Multiple myeloma 2,012 1,046 966 1,171 639 532

Leukemia 3,865 2,237 1,628 2,102 1,231 871

Other and ill defined 22,987 11,610 11,377 5,882 3,283 2,599

CNS, central nervous system.

a) Includes the liver and intrahepatic bile duct,

b) Includes the gallbladder and other/unspecified parts of the biliary tract,

c) Includes the lung and bronchus.

Table 2
Estimated crude and age-standardized cancer incidences by sex during 2021 in Korea
Site Crude incidence rates per 100,000 Age-standardized incidence rates per 100,000a)


Both sexes Men Women Both sexes Men Women
All sites 501.7 524.7 478.8 266.5 280.0 265.2

Lip, oral cavity, and pharynx 7.9 11.3 4.4 4.3 6.3 2.5

Esophagus 5.1 9.2 0.9 2.3 4.5 0.4

Stomach 51.7 69.3 34.1 25.0 35.8 15.7

Colon and rectum 54.4 66.2 42.6 25.6 34.4 17.7

Liverb) 28.4 42.5 14.3 13.5 22.0 5.8

Gallbladderc) 16.1 17.3 14.9 6.7 8.3 5.4

Pancreas 17.0 17.7 16.3 7.6 8.9 6.5

Larynx 2.1 3.9 0.2 0.9 1.9 0.1

Lungd) 62.0 82.1 42.1 27.5 39.7 18.1

Breast 52.0 0.4 103.2 31.9 0.2 63.6

Cervix uteri 6.0 - 12.0 3.9 - 7.8

Corpus uteri 6.7 - 13.3 4.0 - 8.0

Ovary 5.9 - 11.9 3.6 - 7.2

Prostate 32.3 64.8 - 14.3 31.5 -

Testis 0.6 1.3 - 0.7 1.3 -

Kidney 12.1 16.6 7.5 6.7 9.6 3.9

Bladder 9.8 15.6 4.0 4.2 7.6 1.6

Brain and CNS 4.2 4.5 3.9 3.0 3.4 2.7

Thyroid 60.1 30.7 89.3 43.8 22.1 66.3

Hodgkin lymphoma 0.7 0.8 0.5 0.6 0.7 0.5

Non-Hodgkin lymphoma 11.2 12.9 9.5 6.6 8.1 5.3

Multiple myeloma 3.9 4.1 3.7 1.8 2.0 1.6

Leukemia 7.5 8.7 6.3 5.6 6.6 4.6

Other and ill defined 44.4 44.9 43.8 22.7 25.4 20.3

CNS, central nervous system.

a) Age adjusted to the world standard population,

b) Includes the liver and intrahepatic bile duct,

c) Includes the gallbladder and other/unspecified parts of the biliary tract,

d) Includes the lung and bronchus.

Table 3
Estimated cancer incidence by age group and sex during 2021 in Korea
Rank Age group (yr)
0–14 15–34 35–64 ≥65
Men
 1 Leukemia (4.8) Thyroid (22.9) Stomach (65.3) Lunga) (426.0)
 2 Non-Hodgkin lymphoma (3.3) Leukemia (3.9) Colon and rectum (61.7) Prostate (351.5)
 3 Brain and CNS (2.3) Non-Hodgkin lymphoma (3.3) Thyroid (44.4) Stomach (264.8)
 4 Kidney (0.4) Testis (3.0) Lunga) (44.0) Colon and rectum (251.3)
 5 Testis (0.3) Colon and rectum (2.9) Liverb) (42.3) Liverb) (154.5)
Women
 1 Leukemia (4.0) Thyroid (69.3) Breast (171.6) Colon and rectum (150.0)
 2 Brain and CNS (2.1) Breast (12.1) Thyroid (135.1) Lunga) (142.8)
 3 Non-Hodgkin lymphoma (1.7) Cervix uteri (5.6) Lunga) (33.0) Breast (108.0)
 4 Ovary (0.8) Ovary (3.5) Stomach (30.9) Stomach (104.3)
 5 Thyroid (0.6) Corpus uteri (2.7) Colon and rectum (30.5) Pancreas (65.1)

CNS, central nervous system.

a) Includes the lung and bronchus,

b) Includes the liver and intrahepatic bile duct.

Table 4
Estimated crude and age-standardized cancer mortality rates by sex during 2021 in Korea
Site Crude mortality rates per 100,000 Age-standardized mortality rates per 100,000a)


Both sexes Men Women Both sexes Men Women
All sites 157.4 192.1 122.9 65.6 92.6 45.5

Lip, oral cavity, and pharynx 2.4 3.5 1.3 1.1 1.8 0.5

Esophagus 2.4 4.4 0.5 1.0 2.0 0.2

Stomach 11.2 14.9 7.6 4.5 7.2 2.4

Colon and rectum 17.1 19.0 15.2 6.8 9.2 4.9

Liverb) 19.0 27.2 10.9 8.3 13.5 3.6

Gallbladderc) 10.4 11.2 9.6 4.0 5.2 2.9

Pancreas 13.6 14.1 13.1 5.6 6.9 4.6

Larynx 0.5 0.9 0.1 0.2 0.4 0.0

Lungd) 35.5 52.7 18.4 14.0 24.4 6.2

Breast 5.5 0.1 10.9 2.9 0.0 5.7

Cervix uteri 1.5 - 3.1 0.8 - 1.5

Corpus uteri 0.8 - 1.6 0.4 - 0.7

Ovary 2.6 - 5.2 1.3 - 2.4

Prostate 4.1 8.3 - 1.4 3.7 -

Testis 0.0 0.1 - 0.0 0.1 -

Kidney 2.3 3.2 1.4 1.0 1.6 0.5

Bladder 3.0 4.5 1.6 1.1 2.1 0.4

Brain and CNS 2.7 2.8 2.6 1.6 1.7 1.4

Thyroid 0.7 0.4 1.0 0.2 0.2 0.3

Hodgkin lymphoma 0.1 0.2 0.1 0.1 0.1 0.0

Non-Hodgkin lymphoma 4.3 5.0 3.7 1.8 2.4 1.3

Multiple myeloma 2.3 2.5 2.1 0.9 1.2 0.7

Leukemia 4.1 4.8 3.4 2.0 2.6 1.5

Other and ill defined 11.4 12.7 10.0 4.9 6.5 3.7

CNS, central nervous system.

a) Age adjusted to the world standard population,

b) Includes the liver and intrahepatic bile duct,

c) Includes the gallbladder and other/unspecified parts of the biliary tract,

d) Includes the lung and bronchus.

References

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