key: cord-0752551-in483jb0 authors: Cao, Wei; Chen, Hong-Da; Yu, Yi-Wen; Li, Ni; Chen, Wan-Qing title: Changing profiles of cancer burden worldwide and in China: a secondary analysis of the global cancer statistics 2020 date: 2021-04-05 journal: Chin Med J (Engl) DOI: 10.1097/cm9.0000000000001474 sha: 1a2965dd8b6d9a42d3a960525c7a3530bf05fde0 doc_id: 752551 cord_uid: in483jb0 BACKGROUND: Cancer is one of the leading causes of death globally, but its burden is not uniform. GLOBOCAN 2020 has newly updated the estimates of cancer burden. This study summarizes the most recent changing profiles of cancer burden worldwide and in China and compares the cancer data of China with those of other regions. METHODS: We conducted a descriptive secondary analysis of the GLOBOCAN 2020 data. To depict the changing global profile of the leading cancer types in 2020 compared with 2018, we extracted the numbers of cases and deaths in 2018 from GLOBOCAN 2018. We also obtained cancer incidence and mortality from the 2015 National Cancer Registry Report in China when sorting the leading cancer types by new cases and deaths. For the leading cancer types according to sex in China, we summarized the estimated numbers of incidence and mortality, and calculated China's percentage of the global new cases and deaths. RESULTS: Breast cancer displaced lung cancer to become the most leading diagnosed cancer worldwide in 2020. Lung, liver, stomach, breast, and colon cancers were the top five leading causes of cancer-related death, among which liver cancer changed from the third-highest cancer mortality in 2018 to the second-highest in 2020. China accounted for 24% of newly diagnosed cases and 30% of the cancer-related deaths worldwide in 2020. Among the 185 countries included in the database, China's age-standardized incidence rate (204.8 per 100,000) ranked 65th and the age-standardized mortality rate (129.4 per 100,000) ranked 13th. The two rates were above the global average. Lung cancer remained the most common cancer type and the leading cause of cancer death in China. However, breast cancer became the most frequent cancer type among women if the incidence was stratified by sex. Incidences of colorectal cancer and breast cancer increased rapidly. The leading causes of cancer death varied minimally in ranking from 2015 to 2020 in China. Gastrointestinal cancers, including stomach, colorectal, liver, and esophageal cancers, contributed to a massive burden of cancer for both sexes. CONCLUSIONS: The burden of breast cancer is increasing globally. China is undergoing cancer transition with an increasing burden of lung cancer, gastrointestinal cancer, and breast cancers. The mortality rate of cancer in China is high. Comprehensive strategies are urgently needed to target China's changing profiles of the cancer burden. Cancer is one of the leading causes of death globally, but its burden is not uniform. [1] The cancer burden has grown over time in both developed and developing countries due to the complex reasons involved, which include aging and burgeoning population, accelerating socioeconomic development, and changes in the prevalence of associated risk factors. [2, 3] With the population expanding and aging worldwide, cancer is the primary cause of premature death and decreases life expectancy in many countries. [4] However, disparities in the patterns of cancer diagnoses have been observed. Countries with varying human development index (HDI) have different profiles of common cancer types. For example, colorectal and prostate cancers are common among men in high HDI areas, whereas cervical cancer occurs more frequently in women in low HDI areas. [5] Moreover, standardized incidence rates for some of the leading cancer types are 200% to 300% higher in transitioned economies than in transitioning economies. [2] Countries at the transitioning stage face a predominance of infection-related cancers and an increasing cancer burden that is associated with Western lifestyles. China is one of the countries in the transitioning stage of cancer. [6] The incidence and mortality profiles of China are changing from those of developing countries to those of developed countries. [7] Since China has a population of 1.4 billion, even minimal increases in incidence or mortality rates indicate great threats to individuals at risk and a significant economic burden. Cancer transition increases the difficulty of cancer prevention and control. [8] Therefore, an understanding of the contemporary cancer transition and an analysis of the changing profiles of China's cancer burden are urgently needed to ensure that targeted cancer prevention and control could be tailored and implemented. GLOBOCAN 2020 provided updated estimates of cancer incidence and mortality at the end of 2020. It is estimated that the number of new cancer cases reached 19.3 million globally, and nearly 10 million people died from cancer in 2020. [9] Furthermore, female breast cancer displaced lung cancer and became the most substantially diagnosed cancer for the first time. The current study provides an overview of cancer incidence and mortality in 2020 based on the most recent data compiled by the International Agency for Research on Cancer (IARC), the changing profiles of leading cancer types worldwide and in China, projected cancer incidence and mortality over the next two decades, and the implications of the above factors for cancer research and control. A descriptive secondary analysis was conducted using data extracted from the GLOBOCAN 2020 database, as visualized in CANCER TODAY (https://gco.iarc.fr/to day/home). The IARC newly released the estimates of the global cancer burden for the year 2020, including incidence, mortality, and prevalence in 185 countries or territories for 36 types of cancer. The methods for estimating the cancer burden in GLOBOCAN 2020 are country-specific and have been described in detail in a previous study. [10] The quality of the national estimates is largely determined by the coverage and accuracy of the recorded cancer data for each country. The database is accessible online at the IARC Global Cancer Observatory, where a comprehensive assessment of global cancer statistics is systematically quantified to inform cancer research and control via an interactive web-based platform (https://gco.iarc.fr/). We extracted the number of new cases and cancer deaths from the GLOBOCAN 2018 [2] and 2020 databases for the most common cancer types and all cancers combined. Cancer profiles, both worldwide and by continent (as well as by specific countries on each continent), are also available in the GLOBOCAN database, which uses the best available cancer data within each country. We obtained cancer incidence and mortality data explicitly for China from the 2015 National Cancer Registry Report published in China [3] and GLOBOCAN 2020, when sorting the leading cancer types by new cases and deaths for the years 2015 and 2020. The countryspecific data for China in the GLOBOCAN 2020 were built on the recent local data from 91 cancer registries in China. [10] To assess the future cancer burden, we referred to the predicted incidence and mortality, as shown in CANCER TOMORROW (https://gco.iarc.fr/tomorrow/ en), for six continents and China through 2040. The projected number of new cancer cases and deaths in a country for a specific year is calculated by multiplying the age-standardized incidence rate (ASIR) or age-standardized mortality rate (ASMR) estimated in 2020 with the corresponding expected population size for that specific year. [11] The important assumption of the prediction is that the rates in 2020 remain consistent during the prediction period. [9] For ethical considerations, the authors are accountable for all aspects of the work for ensuring the accuracy or integrity of any part of the work. First, we described the 14 leading cancer types globally for new cases and deaths, respectively, with rank changes from 2018 to 2020. We then characterized the cancer incidence and mortality on six continents and in certain countries with a maximum number of cases within each continent. The cancer burdens of the countries mentioned above were ranked by the crude and ASIRs, as well as the crude and ASMRs. Next, the estimated numbers of new cases and deaths for the common cancer types were compiled explicitly for China in 2015 and 2020. For the top ten leading cancer types according to sex in China, we summarized the incidence and mortality, and calculated China's percentage of the new cases and deaths in the world. Finally, the projected data of cancer incidence and mortality from 2020 to 2040 were utilized to analyze the future burden of cancer. Changing global profiles of leading cancer types Figure 1 illustrates that for both sexes combined, female breast cancer was the most frequent cancer in 2020, surpassing lung cancer. Prostate cancer, non melanoma of the skin, and colon cancer ranked third, fourth, and fifth, respectively, followed by stomach, liver, and rectal cancers. Cervical cancer remained the ninth most common type of cancer, surpassing esophageal cancer. Overall, the top 14 cancer types accounted for nearly 75% of newly diagnosed cases in 2020 (69% when non-melanoma of skin cancer was excluded). After sorting by cancer deaths in both sexes in 2020, lung, liver, stomach, breast, and colon cancers were the top five leading causes of death, closely followed by esophageal, pancreatic, and prostate cancers. Notably, stomach cancer deaths decreased by nearly 14,000 cases in 2020. Liver cancer changed from the third-highest cancer mortality in 2018 to the second-highest in 2020. Among the 14 most common cancers, deaths due to breast cancer increased the most. Table 1 indicates the distribution of 19.3 million new cancer cases and Table 2 indicates the distribution of an estimated 10 million cancer deaths in the year 2020. Approximately half of the new cancer cases and 58% of Chinese Medical Journal 2021;134 (7) www.cmj.org As shown in Figure 2 , the distribution of new cases and deaths related to China's most common cancer types is depicted for 2015 and 2020. Lung cancer remained the most common cancer, followed by colorectal and gastric cancer, and had an estimated 0.82 million new cases in 2020 in China. Breast cancer, replacing liver cancer, was estimated to be the fourth most common cancer diagnosed, with the number of new cases increasing from 0.3 million in 2015 to 0.42 million in 2020. Liver cancer and esophageal cancer ranked as the fifth and sixth leading types of cancer, respectively, with an estimated 0.41 million and 0.32 million new cases, respectively. In terms of cancer mortality in China, lung cancer was the leading cause of death, responsible for 0.72 million deaths in 2020. According to the number of deaths, the top five most common cancers Figures 3 reveal that an estimated 49% increase in new cases and a 62% increase in deaths will occur on six continents in 2040 compared with 2020. China is expected to experience 6.85 million new cancer cases and 5.07 million deaths in 2040. Asia, Latin America and the Caribbean, and Africa are projected to undergo a striking relative magnitude of increased incidence and mortality. Moreover, the absolute cancer burden will continue to increase over the next 20 years. With the increasing incidence and mortality, cancer remains a primary public health problem. The changing profiles of the most common cancer types revealed that breast cancer replaced lung cancer as the most diagnosed cancer globally in 2020. The incidence of breast cancer has increased in both high-HDI and low-HDI countries, and the ASIR in more developed regions is 2 to 4 times that in less developed regions. [1, 9] Potential reasons for this increase may be ongoing changes in reproductive practices, including declining fertility rates, postponement of the first childbearing, and breastfeeding for shorter durations. [12] Excess body weight and a high body mass index are also associated with increased breast cancer risk among older women, especially after menopause. [13, 14] Moreover, variations in breast cancer incidence also reflect disparities in the prevalence and distribution of risk factors in different areas. Countries undergoing rapid societal and economic development are more likely to experience changes in the breast cancer profiles of their population. [15] We also observed rank changes in the mortality attributable to liver cancer, which is currently the second leading cause of cancer-related deaths globally. Etiologically, hepatitis B/C virus infections and alcohol use are responsible for more than 80% of liver cancer deaths. [16] Previous studies illustrated that liver cancer mortality varies considerably depending on the patient's age groups, sex, ethnicity, educational attainment, and geographic area. [17, 18] Targeted interventions, including vaccination, disruption of hepatitis virus transmission, antiviral treatment, and reduced alcohol consumption, are urgently needed to halt the growing burden of liver cancer. In China, comparing new cases and deaths by cancer type between 2015 and 2020 exhibits the changing profiles of the cancer burden. Lung cancer remains the most common cancer type and the leading cause of cancer-related deaths. Tobacco consumption, air pollution, and occupational exposure are the primary carcinogens that contribute to lung cancer incidence. [19] China is experiencing cancer transitioning stage with substantial increases in the new cases of colorectal cancer and female breast cancers. In high-HDI countries, lung, colorectal, and female breast cancers, possibly associated with a Westernized lifestyle, are responsible for nearly one-half of the total cancer incidence. [5] China's cancer incidence profile is becoming similar to that of high-HDI countries. However, the leading causes of cancer-related mortality remained consistent between 2015 and 2020. The cancer mortality rate is higher in China than in developed countries. In addition to lung cancer, gastrointestinal cancers account for 45% of the cancer-related deaths in China, whereas the corresponding figure is much lower in developed countries (eg, the USA and the UK). [7] A possible explanation for this finding is that gastrointestinal cancers may have poorer prognoses, and late-stage presentation may be more common in China. An updated overview of cancer epidemiology would improve our understanding of the cancer patterns and possibly help tackle cancer burden more efficiently in China. The analysis of projected incidence and mortality indicated that the cancer burden will continue to increase over the next 20 years. Much is still required to fight against cancer. However, a "one-size-fits-all" strategy for cancer preven- Chinese Medical Journal 2021;134 (7) www.cmj.org tion and control does not seem to be effective. Consider China as an example, the level of cancer awareness is inversely associated with cancer risk in rural China. [20] Health promotion and education that disseminate cancer knowledge and improve cancer development perceptions are crucial in real practice. [21] As potentially modifiable risk factors have been identified across all provinces in China, [22] tailored healthier lifestyles should be persistently recommended across different areas. Organized cancer screening programs funded by the Chinese government have been implemented for several years in rural and urban China to explore appropriate strategies for early cancer detection. [23, 24] Comprehensive strategies, including vaccination programs and tobacco control policies, also need to be developed. [25] The estimated incidence and mortality vary substantially across continents and countries. In addition to several socioeconomic and lifestyle factors, it is noteworthy that the coverage and data quality of the cancer registry play a critical role in cancer surveillance. [26] Currently, highquality registry data are not extensively available in most low-and middle-income countries. For instance, cancer registries cover only small proportions of the population (less than 10%) in Latin America and Asia, whereas the corresponding figure is 98% in the USA. [27, 28] China's national cancer registry has made remarkable improvements in data representativeness and quality since its establishment in 2002. [29] The total number of local population-based cancer registries has increased significantly from 501 in 2015 to 1152 in 2020, presently covering up to 598 million people in China. [3, 30] However, the data quality in these registries is inconsistent. Persistent efforts should be devoted to improving and achieving more reliable national cancer data, laying a solid foundation for precise burden estimates and evidence-based cancer control programs. GLOBOCAN 2020 has shown that it is vital for global cancer control to deliver cancer prevention and care in transitioning countries. [9] China, a transitioning country, bears a massive burden of cancer incidence and mortality. This study depicts the most recent changing profile of the cancer burden, particularly in China, and compares the cancer data of China with those of other regions. Future implications for tailored policies and targeted practices on cancer control in China may be drawn from the findings of this study. However, potential limitations should be noted when interpreting the findings. Although GLOBOCAN 2020 provides reasonably accurate estimates of recent cancer data, caution should be exercised when evaluating the real burden under the impact of the global COVID-19 pandemic on decreased access to health care and delayed cancer diagnosis. Second, the cancer burden varies considerably according to sex, age group, race/ethnicity, and geographic location. [31] Cancer disparities should be addressed explicitly in research to enable customize targeted cancer control programs. Additionally, by performing our analysis of the future cancer burden using only five years of data, we did not account for other data sources and variables, which could have improved our understanding of the burden and related trends in the near future. The burden of breast cancer is increasing globally. China is undergoing cancer transitioning with an increasing burden of lung cancer, colorectal cancer, and female breast cancer. In China, cancer mortality is high, and gastrointestinal cancers account for 45% of all cancer deaths in 2020. An overview of the updated cancer epidemiology would renew our understanding of the recent cancer burden. Comprehensive strategies, including health education, dissemination of essential cancer knowledge, advocacy of healthy lifestyle, effective cancer screening, vaccination programs, and tobacco-control policies, need to be tailored to target China's cancer pattern. Global cancer patterns: causes and prevention Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries Cancer incidence and mortality in China Years of life lost as a measure of cancer burden on a national level Cancer transition and priorities for cancer control Cancer burden and trends in China: a review and comparison with Japan and South Korea Current cancer situation in China: good or bad news from the 2018 Global Cancer Statistics? Cancer burden and control in China Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries GLOBOCAN 2020 annexes International Agency for Research on Cancer (IARC) International Agency for Research on Cancer (IARC) Dual effects of weight and weight gain on breast cancer risk Proportion of US trends in breast cancer incidence attributable to long-term changes in risk factor distributions International variation in female breast cancer incidence and mortality rates Global Burden of Disease Liver Cancer Collaboration. The burden of primary liver cancer and underlying etiologies from 1990 to 2015 at Temporal trends in liver cancer mortality by educational attainment in the United States Mortality due to cirrhosis and liver cancer in the United States, 1999-2016: observational study Epidemiology of lung cancer in China Association of cancer awareness levels with the risk of cancer in rural China: a population-based cohort study Incidence and mortality of female breast cancer in China, 2014 (in Chinese) Disparities by province, age, and sex in site-specific cancer burden attributable to 23 potentially modifiable risk factors in China: a comparative risk assessment Progress of cancer screening program in urban China (in Chinese) Health economic evaluation of cancer screening in China (in Chinese) Cancer deaths and cases attributable to lifestyle factors and infections in China What is a Cancer Registry XI Lyon, IARC. International Agency for Research on Cancer Progress, challenges and ways forward supporting cancer surveillance in Latin America Cancer statistics in China Cancer statistics Changing profiles of cancer burden worldwide and in China: a secondary analysis of the global cancer statistics 2020 None.