Jpn J Clin Oncol 2010;40(4)281– 285 doi:10.1093/jjco/hyp187 Advance Access Publication 18 January 2010

Review Article: Cancer Trends in Asia

Cancer Trends in China Ping Zhao, Min Dai*, Wanqing Chen and Ni Li Chinese Academy of Medical Sciences, Cancer Institute and Hospital, Beijing, People’s Republic of China *For reprints and all correspondence: Min Dai, Chinese Academy of Medical Sciences, Cancer Institute and Hospital, Beijing, People’s Republic of China. E-mail: [email protected] Received September 17, 2009; accepted December 7, 2009

Cancer is the leading death cause in urban China and the second one in rural China. Lung cancer is the most common cancer, followed by stomach cancer, liver cancer, esophageal cancer and colorectal cancer. Cancer Control Programs in China focus on prevention, early diagnosis and treatment. The prevention program includes an anti-smoking campaign and immunization against hepatitis B for infants and children under the age of 15. Screening for breast and cervix cancers is among efforts for the early detection and treatment. Public education and the promotion of healthy lifestyles have been actively carried out. Key words: cancer trends – China

INTRODUCTION Cancer is one of the most important public health problems in China. Cancer prevention and control becomes one of the most important issues Chinese government is carrying out all over China. For example, in June 2009, China Ministry of Health launched six major public health programs including giving booster shots of the hepatitis B vaccine to those under the age of 15 as the supplementation to the immunization of infants against hepatitis B and providing a free screening program for breast and cervix cancers among the rural women in 200 counties.

BURDEN OF CANCER Although there are no national data on cancer incidence, the three national death cause surveys conducted in the 1970s, 1990s and 2004 – 05 provide us a grave picture about cancer burden in China (1 – 3). Cancer now becomes the major killer in today’s China, representing 25% of all deaths in urban areas and 21% in rural areas (3). Cancer mortality in China has been increasing rapidly and continuously during the past three decades, from 74.2/100 000 in the 1970s to 108.3/100 000 in the 1990s and to 135.9/100 000 in 2004 – 05 (Fig. 1). This trend indicated that risk factors for cancer, such as aging population, deterioration of the environment,

western lifestyles etc., were increasing in China in the past 30 years. However, after age standardization, cancer mortality showed the different trend. Age-standardized cancer mortality largely increased from 1970s to 1990s, but it declined a little afterwards till 2004 – 05. This trend revealed that the aging population played more important role in China since 1990s, which is exactly correspondent with the fact that China became the aging society around 2000 (Table 1). Change of cancer burden in China does not only showed by the overall cancer mortality, but also reflected by the mortality of individual cancers. Figure 2 shows the change of cancer mortality for top 10 cancers during the past three decades. Lung cancer, in particular, increased 465% during the past 30 years and became the leading cancer death cause in the current decade. The WHO estimated that by year 2025, more than 1 000 000 Chinese will be diagnosed with lung cancer alone each year (4). Digestive tract cancers, such as gastric cancer, liver cancer and esophageal cancer, continued to stay among top five cancers during the past three decades, although they showed the different trend. In particular, liver cancer kept an increasing trend in the last 30 years and it is estimated that about 280 000 men and 110 000 women are diagnosed with primary liver cancer each year and about 325 000 patients die each year from this disease. China accounts for almost 50% of the world’s liver cancer

# The Author (2010). Published by Oxford University Press. All rights reserved.

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Figure 1. Crude and age-standardized cancer mortality in People’s Republic of China in 1970s, 1990s and 2004– 05. The population from census of China in 1982 was used as standard population.

Table 1. Age-specific proportions (%) of the population in China Age groups (years)

Survey time (year) 1964

1982

1990

2000

2005

2008

0–14

40.4

33.6

27.7

27.0

20.3

19.0

15– 59

53.5

58.8

63.7

63.2

68.7

69.0

6.1

7.6

8.6

9.8

11.0

12.0

60

cases (4). Mortality of breast cancer among women has decreased a lot but incidence has doubled during the past 30 years (4). Other major cancers in China, such as colorectal cancer and leukemia, are increasing. Cancer varies largely in China between urban and rural areas. Mortality of cancer is higher in urban (150.18/100 000) than in rural areas (128.65/100 000). Table 2 shows the top 10 cancers among urban and rural areas in China in 2004–05. Lung cancer is the leading one in urban areas, followed by digestive tract cancers (liver cancer, gastric cancer and esophageal cancer and colorectal cancer). In contrast, liver cancer is the leading cause in rural areas, followed by lung cancer, other digestive tract cancers.

Figure 2. Changes of cancer mortality rate for top 10 cancers.

Using the above mortality data, cancer incidence rates were estimated in good quality cancer registries in China (5). A total of 2.1 million cancer cases were estimated for the year 2000 (1.3 million in men and 0.8 million in women), with the most common sites being lung, liver and stomach in men, and breast, lung and stomach in women. The total number of new cases is expected to increase by 14.6% by 2005, primarily as a result of population growth and aging. In addition, the rising rates of lung cancer incidence (in both sexes) and breast cancer mean that there will be much greater increases in the number of cases at these two sites (27% for lung cancer in men and 38% for lung and breast cancers in women). These two cancers should now be the priorities for cancer prevention, early detection and therapy in China. The direct and indirect economic costs of cancer are high in China. According to the National Health Service survey in 2003, cancer had the highest economic costs among all diseases. Total economic cost from cancer was 86.85 billion RMB with the direct cost of 28.45 billion RMB and the indirect cost of 58.40 billion RMB, which accounted for 7.23% of the total economic cost of diseases (6). Given the increasing trend in cancer mortality, the economic cost of cancer in China is probably to grow. In the USA, a welldeveloped country with the increasing cancer incidence and

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Table 2. Top 10 cancers among urban and rural areas in People’s Republic of China, 2004– 05 Urban areas

Rural areas

Mortality (/100 000)

Proportion (%)

Mortality (/100 000)

Proportion (%)

26.93

20.94

1

Lung cancer

40.98

27.29

Liver cancer

2

Liver cancer

24.93

16.6

Lung cancer

25.71

19.99

3

Gastric cancer

22.97

15.3

Gastric cancer

25.58

19.89

4

Esophageal cancer

10.97

7.31

Esophageal cancer

17.34

13.48

5

Colorectal cancer

9.78

6.51

Colorectal cancer

5.96

4.64

6

Pancreas cancer

4.44

2.96

Leukemia

3.68

2.86

7

Leukemia

4.17

2.78

Brain tumor

2.8

2.18

8

Female breast cancer

3.98

2.65

Female breast cancer

2.35

1.83

9

Brain tumor

3.77

2.51

Pancreas cancer

1.7

1.32

10

Gallbladder cancer

2.13

1.42

Bone cancer

1.61

1.25

mortality in the last tens of years and higher cancer burden than China, the total cost of cancer in 2005 was US$209.9 billion (7).

RISK FACTORS FOR CANCERS China is the world’s largest tobacco production and consumption country with more than 350 million current tobacco smokers and an additional 500 million people exposed to passive smoking everyday (8). Even more alarming is the fact that there are 15 million regular smokers aged between 13 and 18 years, and an additional 40 million casual smokers in this age range. Average age to start smoking is decreasing from age 22 in 1984 to 19 in 1996 and to 18 in 2002, although the Law of the People’s Republic of China on the Protection of Minors (younger than 18 years) issued in 1999 prohibited the sale of cigarettes to minors. The smoking rate among males (around 60%) is extremely higher than among females (around 4%) and had an insignificant decrease compared with the rate of 10 years ago. However, an increasing trend of smoking rate started to be seen among females, particularly among young females with the increasing speed of 10% annually. Infectious agents are responsible for a high percentage of the cancer burden in China. The role of Helicobacter pylori in causing gastric cancer is well documented and the treatment of H. pylori led to a reduction in the prevalence of precancerous gastric lesions (9). In a high-risk area to stomach cancer, Linqu County in Shandong Province, a 68% positive rate of H. pylori infection was reported among the adults aged 35 – 64 years (10). The causal role of hepatitis B in hepatocellular carcinoma is also well documented. According to the result of a nationwide cross-sectional seroepidemiologic study of hepatitis A, B, C, D and E virus infections in China in 1992, the overall prevalence of HBsAg carrier was 9.75% (11) and China had about 120 million

hepatitis B virus (HBV) carriers at one time (12). Scientific evidence supported a causal role for Epstein – Barr virus (EBV) infection in nasopharyngeal carcinoma, one of carcinomas common in Southeast China, and serological screening for EBV could significantly increase the rate of early detection of nasopharyngeal cancer (13). The proportion of people with overweight and obesity is increasing rapidly in China, especially in the urban areas, due to increasing consumption of animal meat products and physical inactivity. According to the data from the national nutrition and health survey in 2002, 14.7% of Chinese were overweight (body mass index, BMI  25) and another 2.6% were obese (BMI  30), such that there are currently 184 million overweight people, and a further 31 million obese people in China, out of a total population of 1.3 billion (14).

NATIONAL CANCER CONTROL PROGRAMS IN CHINA In 1986, China National Office for Cancer Prevention and Control developed the first National Cancer Control Plan (1986 – 2000). This plan aimed to reduce the incidence and mortality rates of cancer and improve the survival and quality of life of cancer patients. It also outlined the need to carry out studies to improve the prevention and control of several cancers including cancers of stomach, esophagus, liver, lung, colorectum, cervix uteri, breast, nasopharynx and leukemia. After completing the first cancer control plan, China Ministry of Health evaluated the effectiveness of its control effort and confirmed the role of comprehensive intervention and control strategies in decreasing the cancer mortality in high-risk rural areas (e.g. Lin County in Henan Province, high risk to esophageal cancer). Building on the first plan, the Ministry developed the second National Cancer Control Plan (2004 – 10). About the same time, China developed the Hepatitis B Prevention and Control

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Plan (2006 – 10). Through the implementation of these two complementary plans, the Ministry hopes to accelerate the cancer prevention and control efforts in China. In order to lead the nationwide efforts to prevent and control cancer, the Ministry is establishing China National Cancer Center. The anti-smoking campaign has been initiated in China for a couple of years and several programs are ongoing. China signed the WHO Framework Convention on Tobacco Control in 2003 and ratified it in 2005. The convention went into effect in China in January 2006. In 2005 and 2006, Chinese government provided a special fund of more than 10 million RMB to improve the ability of tobacco control including building the national tobacco control network, creating the smoke-free places, establishing the surveillance system on tobacco smoking among high-risk populations and providing the service for quitting smoking. In April 2007, a program aiming at preventing the passive smoking—‘Towards a Smoke-free China’—was initiated with the special fund from Bloomberg School of Public Health of John Hopkins University. In 2008, being the first country to host the Olympic Games since the Convention came into effect, China organized a complete smoke-free green Olympic. Vaccination of infants against hepatitis B was initiated in 1992. From then on, China has put tremendous efforts in implementing mass vaccination. The overall coverage of hepatitis B vaccine in infants has increased steadily and reached more than 95% in urban and 83 2 97.0% in rural areas in 2005 (12). The chronic HBV carrier rate in children younger than 10 years of age decreased from 10% before the mass vaccination to 1 – 2% in 2006 and that in general population decreased from 10% to 7.2%. Overall, the nationwide mass HBV vaccination has reduced more than 30 million of chronic HBV infections and HBV-related severe sequelae, although no obvious decline has been observed for liver cancer yet (12). In order to broaden the effect of HBV vaccination, in June 2009, China launched a program giving booster shots of the hepatitis B vaccine to those under the age of 15. According to this plan, the hepatitis B vaccination will be given to all non-immune people born between 1994 and 2001 nationwide within 3 years. Early detection and treatment is the important aspect of cancer prevention and control. It was initiated in 2004 with the special fund from China Ministry of Health and focusing on screening programs on breast cancer, cervix cancer and digestive tract cancers. Till now, 530 000 women and 113 000 women were screened for breast cancer and cervical cancer, respectively, with this special fund. After some trials in cities and counties, China is now expanding the population coverage of screening programs, particularly on cervical cancer and breast cancer. In urban areas where the medical condition and insurance are well established, screening for cervical cancer and breast cancer is covered by medical insurance. In rural areas, a program just issued in June 2009 will screen these two cancers for free among all the women in 200 counties (more than 1500 counties in total in China). Moreover, in some high-risk areas for digestive

tract cancers such as Huaihe Region, a program to screen gastric cancer, liver cancer and esophageal cancer is ongoing with the special fund from the government. The first death cause survey in 1973 – 75 identified more than 60 high-risk areas for specific cancers including cancer of the stomach, esophagus, liver, nasopharynx and cervix, mostly in rural areas. Since then, many experts on epidemiology, clinic and basic research worked together to carry out the various interventional studies to control the cancers in these high-risk areas. For example, Lin County was famous for its high risk for esophageal cancer for a long period. Since 1970s, several working groups composed of epidemiologists, clinicians and researchers have made great effort in controlling the occurrence and death of esophageal cancer. The current result has showed an obvious decline for the incidence and mortality of esophageal cancer in Lin County (15). Moreover, a new cancer prevention system was being explored in urban China with the involvement of three partners (hospital, medical insurance company and health management company). In this system, high-risk population for cancers will be identified based on their reported information during the questionnaire interview and using the mathematical models, and then cancer screening program will be carried out to high-risk population only. Therefore, this system could largely increase the efficiency of the screening program and benefit for both cancer patients and insurance companies. A well-designed cancer prevention and control program aiming at verifying this system is being carried out in some cities in China (personal communication with M.D.).

NON-GOVERNMENT ORGANIZATIONS Cancer Foundation of China (CFC) and China Anti-cancer Association (CACA) are two independent, non-profit organizations dedicated to cancer prevention and control in China. They put its utmost efforts at organizing scientific cooperation and conferences, promoting international non-governmental exchanges, conducting various training courses and seminars, fostering scientific, technological and medical personnel in the field of oncology, compiling and publishing academic periodicals, and mobilizing social forces to take part in popularization and dissemination of the knowledge of cancer prevention and control. In particular, they are actively leading the early detection and treatment programs on breast cancer, cervical caner and digestive tract cancers all over China.

CONCLUSIONS China is facing a big challenge from cancer due to the high incidence and mortality of cancer and the complicated cancer spectrum. Although some programs on cancer prevention and control are being carried out, a long way needs to go. Heterogeneity of cancer types and imbalance of medical resources across China, particularly between urban and rural

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areas, will bring more difficulty in carrying out these programs. The recent medical reform aiming at building the basic medical network will accelerate the process of cancer prevention and control in China.

Conflict of interest statement None declared.

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