Cancer Statistics in Korea: Incidence, Mortality, Survival, and Prevalence in 2023.

Introduction
Cancer is one of the leading causes of death worldwide, with an estimated 19.9 million new cancer cases and 9 million deaths worldwide in 2022 [1]. In Korea, cancer has been the leading cause of death since 1983 [2]. In response to this public health challenge, the National Plan for Cancer Control was implemented in 1996, and its fifth plan (2026-2030) was announced on February 24, 2026. As a fundamental part of the Plan, the Korea Central Cancer Registry (KCCR) publishes cancer registration statistics every year [3]. The National Cancer Screening Program, implemented in 2002, currently provides screening services for stomach, colorectal, breast, cervical, liver, and lung cancers in Korea [4]. This program has contributed to sustained increases in the proportion of localized stage diagnosis and improved survival rates. In this study, we report the most recent nationwide statistics on cancer incidence, survival, prevalence, and mortality, and their temporal trends. Additionally, we provide international comparisons of cancer incidence and mortality to contextualize Korea’s cancer burden in the global landscape.

Materials and Methods

1. Data sources
Annual cancer statistics in Korea are calculated using a national and population-based database of cancer occurrence, the Korea National Cancer Incidence Database (KNCI DB). Every year, the KCCR collects information on patients diagnosed with cancer at hospitals across the country during the past year. The data from the previous year is backed up with information compiled by central and 11 regional cancer registries, including information on cancer patients missed in hospital-based registrations. Hence, it takes 2 years to complete and calculate the year’s KNCI DB and cancer statistics. The KCCR has reported nationwide statistics since 1999; other detailed information on the KCCR and KNCI DB is provided in our previous report [3]. Completeness is an important indicator of data quality, and the 2023 KNCI DB was estimated to be 97.4% complete using the method proposed by Ajiki et al. [5].
Annual mid-year population data and recently updated mortality data including causes of death from 1983 were obtained from the Ministry of Data and Statistics [2]. To confirm the validity of individual vital statuses used in survival and prevalence calculation, the KNCI DB was linked to both mortality and population resident registration data, which were obtained from the Ministry of the Interior and Safety. For international comparisons of cancer incidence and mortality, data were downloaded from the Global Cancer Observatory: Cancer Today (gco.iarc.who.int/today) [1]. The analysis included all cancers, stomach cancer, colorectal cancer, and breast cancer, with real data used for Korea to ensure accurate comparisons. Additionally, for stomach, colorectal, and breast cancer, incidence and mortality rates were compared with major countries, including Japan, China, the United States, the United Kingdom, Germany, and Italy.

2. Cancer classification
All cancer cases had been registered in accordance with the International Classification of Diseases for Oncology, 3rd edition (ICD-O-3) [6]. The range of cancers to be registered and used for the national statistics calculation was limited to records with a behavior code of “/2 (carcinoma in situ)” or “/3 (malignant),” from the morphology (i.e., histology) codes of ICD-O-3, by which a patient was initially enrolled in the KNCI DB. Since 2021, neuroendocrine tumors (ICD-O-3: 8152 and 8240) of colorectal cancer and gastrointestinal stromal tumors (ICD-O-3: 8936) of stomach cancer have been classified as malignant cancers. Similar to previous reports, malignant cancer cases and their statistics were mainly assessed in this article. In addition, the supplementary incidence statistics for carcinoma in situ cases were also calculated separately.
For the convenience of classification and reporting, the ICD-O-3 codes were converted to the classification of the International Classification of Diseases, 10th edition (ICD-10) [7]. Exceptionally, some hematopoietic diseases (myeloproliferative disorders/myelodysplastic syndromes) are not classified as malignant cancer in ICD-10 classification; therefore, their ICD-O-3 codes were used without any conversion. For mortality data, causes of death were coded according to the ICD-10.
We adopted cancer classifications with 24 and 61 types; the former was a modified classification based on the GLOBOCAN cancer dictionary [8], and the latter was the taxonomy used in “Cancer Incidence in Five Continents” [9], and both of them were provided by the International Association of Cancer Registries. In this article, cancer classification with 24 types of cancer was used for description. The summary staging system developed under the Surveillance, Epidemiology, and End Results (SEER) program (i.e., SEER summary staging) [10] was used to categorize the extent of tumor invasion or metastasis.

3. Statistical analyses
Incidence, mortality, and prevalence rates were expressed as crude rates (CRs) or age-standardized rates (ASRs) per 100,000 people. The CR was defined as the total number of newly diagnosed (for incidence) or deceased (for mortality) cases in a year divided by the mid-year population. The ASR was defined as the weighted average of the age-specific rates in which the weights represent the proportions of people in the corresponding age groups in a standard population [11]. ASRs were standardized using Segi’s world standard population [12]. The lifetime risk of cancer in Korea in 2023 was estimated by applying age-specific cancer incidence rates to the probability of being alive and cancer-free at each age, incorporating competing risks of death from other causes [13]. Trends in ASRs were estimated using Joinpoint regression, with a maximum number of two joinpoints. The results were summarized as annual percentage changes with the best model fit, based on a linear model for the natural log-transformed ASRs.
The survival rate of cancer patients, diagnosed between 1993 and 2023, was calculated based on the results of follow-up until December 31, 2024. The 5-year relative survival rate was defined as the ratio of observed survival of cancer patients to expected survival in the general population, adjusting the effects of other causes of death using the standard population life table provided by the Ministry of Data and Statistics [2]. Relative survival rates were estimated using the Ederer II method [14] with some minor corrections, based on an algorithm devised by Paul Dickman [15]. Trends in 5-year relative survival rates were evaluated as percent differences in survival rates between 1993-1995 and 2019-2023.
The mortality-to-incidence (M/I) ratio was calculated as the number of cancer deaths in 2023 divided by the number of newly diagnosed cancer cases in the same year. The M/I ratio is a widely used indicator of cancer prognosis and the effectiveness of cancer control programs at the population level [16].
Prevalent cases were defined as the number of cancer patients alive on January 1, 2024, among all the patients diagnosed with cancer between 1999 and 2023. p < 0.05 was considered statistically significant. Joinpoint 5.0.2. (National Cancer Institute) and SAS ver. 9.4 (SAS Institute) were used for statistical analyses.

Results

1. Incidence
The number of new cancer diagnoses in 2023 increased by 7,296 cases (2.5%) compared to 2022. In 2023, a total of 288,613 people were newly diagnosed with cancer in Korea, of which 52.4% (151,126 cases) were men and 47.6% (137,487 cases) were women (Table 1). The five most diagnosed cancers in Korea were thyroid, lung, colorectal, breast, and stomach cancers. In men, prostate and lung cancers were followed by stomach, colorectal, and liver cancers, whereas in women, breast and thyroid cancers were followed by colorectal, lung, and stomach cancers. These top five cancers in each sex accounted for 62.2% and 65.5% of all cancer cases in men and women, respectively. Among the top ten cancers, the increase in new cancer diagnoses in 2023 compared to 2022 was the largest for prostate (9.0%), followed by thyroid (3.4%), lung (2.6%), and breast cancer (2.0%). Prostate cancer ranked first in cancer incidence among men for the first time, whereas breast cancer has continued to rank first among women. Table 2 provides the CRs and ASRs of cancer incidence in 2023. The CR and ASR of all cancer incidence were 564.3 per 100,000 (593.4 for men and 535.5 for women) and 288.6 per 100,000 (294.6 for men and 293.7 for women), respectively. The difference between CR and ASR implies that the majority of cancer patients in Korea belong to the elderly, as opposed to the world’s standard population, which has a higher proportion of young people. The lifetime risk of cancer was 41.2%. That probability was higher in men (44.6%) than in women (38.2%) (data not shown).
Cancer incidence patterns varied markedly by age groups (Fig. 1). In the childhood population (0-14 years), leukemia, brain and central nervous system (CNS) cancer, and non-Hodgkin lymphoma were the top three cancers in both sexes, accounting for 33.7%, 14.1%, and 8.1% of all cancer cases diagnosed in this age group, respectively. Thyroid cancer was the most common cancer in both sexes among the adolescent and young adult populations (15-34 years), accounting for 54.1% of all cancers diagnosed. The most common cancers in that age group, excluding thyroid cancer, were colorectal cancer and leukemia in men, and breast and colorectal cancer in women. In the 35-64-year age group, men were most commonly diagnosed with colorectal, stomach, thyroid, and lung cancers (collectively accounting for 51.2%), while breast and thyroid cancers were the most common in women (collectively accounting for 55.3%).
Given that 50.4% of all newly diagnosed cases in 2023 occurred in individuals aged 65 years and older, the incidence pattern for the elderly population was further analyzed (Fig. 1C and D). Among those aged 65 years and older, prostate and lung cancers were the most common in men, while colorectal and lung cancers were the most common in women. While most cancers have been shown to increase in incidence with age, thyroid cancer in both sexes and breast cancer in women showed the highest incidence in those in their 30-40s and 40-50s age groups, respectively (Fig. 2).

2. Mortality
Since the causes-of-death statistics were published in 1983, cancer has been the number one cause of death in Korea. As of 2023, a total of 85,271 people (61.2% men and 38.8% women) died of cancer, accounting for 24.2% of all deaths in Korea (Tables 1 and 3). The overall CR for cancer deaths was 166.7 per 100,000, and the rate was approximately 1.6 times higher for men than for women (Table 4). Lung cancer was the leading cause of cancer death in both sexes (CR, 53.8 per 100,000 in men and 19.3 per 100,000 in women), followed by liver and colorectal cancers in men, and colorectal and pancreatic cancers in women. When stratified according to the age at the time of death, the most common causes of cancer mortality in both sexes were as follows: leukemia in their 10s and 20s, stomach cancer in their 30s, breast cancer in their 40s, liver cancer in their 50s, and lung cancer among those 60 years old or older (data not shown).

3. Trends in cancer incidence and mortality
Changes in cancer incidence rates from 1999 to 2023 and mortality rates from 1983 to 2023 are shown in Fig. 3. Compared with 1999, cancer incidence increased by approximately 36.1% and mortality decreased about 44.2% by 2023 (Table 5). Overall cancer incidence increased until the early 2010s, followed by a short decline and a modest increase thereafter. In contrast, cancer mortality remained stable until the early 2000s and has steadily declined since then, with a more rapid decrease in recent years. These patterns were observed in both men and women, although the increase in incidence was more pronounced in women, whereas the decline in mortality was greater in men (S1 and S2 Tables).
Cancer incidence patterns varied by site. Breast, pancreas, corpus uteri, testis, leukemia, lymphoma, ovary, and prostate cancers showed overall increasing trends, whereas stomach, liver, cervical, esophageal, and laryngeal cancers demonstrated consistent declines, with more pronounced decreases in recent years for stomach and liver cancers. Thyroid cancer incidence showed marked fluctuations during the study period, increasing rapidly until 2011, declining until 2016, and rising again thereafter. Overall patterns were similar between men and women, although lung cancer incidence increased in women while decreasing in men (Fig. 4, S1 and S2 Tables).
Cancer mortality rates decreased for most cancer sites in Korea. Mortality from stomach, liver, lung, colorectal, and cervical cancers has declined substantially since the early 2000s. Thyroid cancer mortality also decreased after a brief nonsignificant increase in the early period. In contrast, pancreatic and ovarian cancer mortality showed persistent increases over time. These mortality patterns were generally similar between men and women, although breast cancer mortality in women increased until 2014 and has since remained stable (Fig. 5, S1 and S2 Tables).

4. Trends in stage at diagnosis
In terms of distribution of stage at diagnosis across all cancers, the proportion of localized stage increased from 45.6% in 2005, when stage at diagnosis data collection began, to 51.8% in 2023, reflecting a 6.2 percentage point rise. In contrast, the proportion of distant metastasis cases decreased by 2.5 percentage points over the same period. However, the proportion of distant metastasis cases has remained relatively stable at around 20% throughout the years (Fig. 6).
Among the cancers included in the National Cancer Screening Program, the trends in screening rate, stage at diagnosis, and 5-year relative survival were analyzed for stomach, colorectal, and breast cancer. The screening rate for stomach cancer increased from 39.4% in 2005 to 77.4% in 2024, nearly doubling over this period. Correspondingly, the proportion of localized stomach cancer (including carcinoma in situ) at diagnosis rose from 51.9% in 2005 to 73.1% in 2023, reflecting a 21.2 percentage point increase. Additionally, the 5-year relative survival rate for stomach cancer during 2019-2023 reached 78.6%, marking a 20.6 percentage point improvement compared to the 58.0% survival rate observed in patients diagnosed between 2001 and 2005 (Fig. 7A).
Similarly, the screening rate for colorectal cancer increased from 25.0% in 2005 to 74.4% in 2024, approximately 3.0 times higher. Consequently, the proportion of colorectal cancer cases diagnosed at the localized stage (including carcinoma in situ) increased from 36.4% in 2005 to 57.0% in 2023, reflecting a 20.6 percentage point rise. The 5-year relative survival rate for colorectal cancer during 2019-2023 was 75.6%, showing an 8.6 percentage point increase compared to the 67.0% survival rate for those diagnosed between 2001 and 2005 (Fig. 7B).
For breast cancer, the screening rate rose from 38.4% in 2005 to 70.6% in 2024, nearly doubling. In parallel, the proportion of localized stage (including carcinoma in situ) at diagnosis increased from 60.3% in 2005 to 71.8% in 2023, an improvement of 11.5 percentage points. The 5-year relative survival rate for breast cancer during 2019-2023 reached 94.7%, representing a 6.0 percentage point increase from the 88.7% survival rate among patients diagnosed between 2001 and 2005 (Fig. 7C).

5. International Comparison of incidence and mortality
In the international comparison of cancer incidence and mortality for all cancers, the overall cancer incidence in Korea was 288.6 per 100,000 population, which was higher than Japan (267.1), Germany (274.2), and Italy (284.5), but lower than the United Kingdom (307.8) and the United States (367.0), showing a relatively high incidence rate comparable to developed countries. However, Korea recorded the lowest cancer mortality rate among the major comparison countries, at 64.3 per 100,000 population, which was lower than the rates in Japan (78.6), Germany (99.7), Italy (94.2), the United Kingdom (98.3), and the United States (82.3), as well as other European countries (Fig. 8D).
Next, the incidence and mortality rates of stomach, colorectal, and breast cancer were compared across major countries. The incidence rate of stomach cancer in Korea was the second highest after Japan. However, Korea had the lowest M/I ratio (0.21) among the comparison countries (Fig. 8A). Similarly, the incidence rate of colorectal cancer in Korea was also the second highest after Japan, but the M/I ratio was the lowest at 0.22 (Fig. 8B).
For breast cancer, Korea’s incidence rate was lower than that of the United States, the United Kingdom, Italy, Germany, and Japan, but higher than that of China. The M/I ratio for breast cancer in Korea was 0.08, the lowest among the comparison countries (Fig. 8C).

6. Survival rates
Over the past two decades, when cancer survival statistics have been compiled, the relative survival rates of cancer patients have increased significantly and steadily. The 5-year relative survival rates for all patients diagnosed with cancer in the recent 5 years, from 2019 to 2023 were 73.7% in both sexes; 68.2% in men and 79.4% in women (Table 6). The temporal increasing trends in survival rates, from 42.9% in 1993-1995 to 73.7% in 2019-2023, were maintained even after excluding thyroid cancer (from 41.2% in 1993-1995 to 69.6% in 2019-2023), which has an excellent prognosis with a 5-year relative survival rate of 100%.
After thyroid cancer, survival rates were the highest for prostate and testis cancers in men (96.9% and 96.8%, respectively) and breast cancer in women (94.8%). On the contrary, the survival rates were the lowest for cancers of the pancreas (17.0%), and gallbladder plus other and unspecified parts of the biliary tract (29.0%) in both sexes. Prostate cancer (men), lung cancer (women), stomach cancer (both sexes), and lip, oral cavity, and pharynx (men) were associated with outstanding improvements in survival rates over the observed period. In contrast, brain and CNS cancer showed a decline in both sexes.
In terms of stage distribution at diagnosis and recent survival rates according to the SEER summary stage in each cancer, Fig. 9 shows the top 10 most common cancers for each sex in 2023. In men, bladder, kidney, and stomach cancers revealed the highest proportions of patients who were diagnosed at the localized stage (73.5%, 73.3%, and 65.3%, respectively), accompanied by the 5-year survival rates of 87.3%, 99.0%, and 98.3%, respectively. In contrast, pancreatic and lung cancers demonstrated the highest proportions of patients diagnosed at the distant metastatic stage, which approximated to 45%, with corresponding 5-year survival rates of 2.5% and 11.1%, respectively. In women, 71.4%, 65.3%, and 61.0% of uterine corpus, stomach, and breast cancers, respectively, were diagnosed at the localized stage, with 5-year survival rates of 96.4%, 96.3%, and 99.2%, respectively. However, more than 40% of pancreatic and ovarian cancers were diagnosed at the distant metastatic stage, with 5-year survival rates of 2.2% and 45.3%, respectively.

7. Prevalence rates
The total prevalent cancer cases in 2023 (identified as survivor at the time of January 1, 2024) were 2,732,906, surpassing 2 million since 2018 (Table 1). It suggested that one in 19 people (5.3% of the entire Korean population; 4.7% of men and 6.0% of women) has a history of being diagnosed with cancer. Of these, 1,408,234 (51.5% of all prevalent cases) were aged ≥ 65 years, indicating that one in seven people in that age group (17.9% of, or one in six, men and 12.5% of, or one in eight, women) would have experienced cancer (data not shown).
Table 7 provides the CRs and ASRs of prevalence for all cancers combined and for specific cancers. In total, the cancer prevalence rate for 2023 in Korea was 5,343.4 per 100,000 people. Thyroid cancer had the highest prevalence (CR, 1,148.3 per 100,000; 456.8 per 100,000 for men and 1,834.1 per 100,000 for women), followed by stomach cancer (CR, 717.0 per 100,000) and breast cancer (CR, 693.5 per 100,000). Following this, Colorectal cancer in men and breast cancer in women revealed the highest prevalence rates (CR, 785.4 and 1,376.4 per 100,000, respectively).
The number of prevalent cases for common cancers, according to the time since cancer diagnosis, are described in Fig. 10. In total, 1,697,799 (62.1% of all prevalent cases) had survived > 5 years after cancer diagnosis, majority of them being survivors of thyroid, stomach, breast, and colorectal cancers. Another 552,373 (20.2% of all prevalent cases) have been alive 2-5 years after their cancer diagnosis, in which period they need regular follow-up; and the rest were 482,734 (17.7% of all prevalent cases) for whom it had been < 2 years since their cancer diagnosis, in which period they still need active cancer treatment.

8. Carcinoma in situ incidence
A summary of carcinoma in situ cases in 2023 is provided as a Supplementary Material (S3 Table, S4 Fig.).

Discussion
The 2023 cancer statistics reflect ongoing demographic changes in Korea, particularly rapid population aging, with individuals aged 65 years and older account for 50.4% of all newly diagnosed cases. This demographic transition is accompanied by shifts in the cancer profile, including the emergence of prostate cancer as the most common cancer in men.
These patterns have occurred alongside national cancer control efforts and are reflected in the divergence between increasing incidence and decreasing mortality. Over time, the proportion of caners diagnosed at a localized stage has increased, while distant-stage disease has slightly declined. These findings are consistent with the expansion of population-based cancer screening and improvements in access to diagnostic services, although potential contributions from lead-time effects and changes in diagnostic practices should also be considered.
The international comparison analysis, first introduced in the 2022 report, provides a useful benchmark for evaluating cancer control and performance [17]. Korea showed the lowest M/I ratios for stomach (0.21), colorectal (0.22), and breast (0.08) cancers among major high-income countries. These findings may reflect differences in stage distribution at diagnosis, access to treatment, and overall healthcare system performance. However, direct comparisons should be interpreted with caution due to differences in data sources and reference years, as international estimates are based on GLOBOCAN 2022, whereas Korean data are derived from observed national statistics for 2023.
With continued improvements in early detection and treatment, the number of cancer survivors has steadily increased, exceeding 2.7 million in 2023. Notably, more than 60% of these individuals have survived for over 5 years after diagnosis, highlighting the growing importance of long-term survivorship care. At the same time, cancers with poor prognosis, such as pancreatic cancer and biliary tract cancers, continue to pose substantial challenges, with persistently low survival rates.
This study has several limitations. First, cancer incidence data are subject to a 2-year reporting delay due to the time required for data collection and validation. Second, international comparisons rely on modeled estimates for other countries, which may limit comparability with observed national data. Despite these limitations, the KNCI DB provides comprehensive and high-quality population-based data, supporting the reliability of these findings.
In conclusion, Korea has achieved substantial improvements in cancer survival and mortality outcomes over the past two decades. However, as the country enters a super-aged society, the overall cancer burden and the number of survivors are expected to continue increasing. These findings underscore the need for sustained cancer control efforts, with an increasing focus on survivorship care and management of high-mortality cancers.