Chinese Journal of Cancer Original Article Wan 鄄 Qing Chen, Rong 鄄 Shou Zheng and Si 鄄 Wei Zhang Abstract Liver cancer is a common cancer and a leading cause of cancer deaths in China. To aid the government in establishing a control plan for this disease, we provided real 鄄 time surveillance information by analyzing liver cancer incidence and mortality in China in 2009 reported by the National Central Cancer Registry. Liver cancer incidence and cases of death were retrieved from the national database using the ICD 鄄 10 topography code 野 C22 冶. Crude incidence and mortality were calculated and stratified by sex, age, and location (urban/rural). China 爷 s population in 1982 and Segi (world) population structures were used for age 鄄 standardized rates. In cancer registration areas in 2009, the crude incidence of liver cancer was 28.71/100,000, making it the fourth most common cancer in China, third most common in males, and fifth most common in females. The crude mortality of liver cancer was 26.0/100,000, making it the second leading cause of cancer death in China and urban areas and the third leading cause in rural areas. Incidence and mortality were higher in males than in females and were higher in rural areas than in urban areas. The age 鄄 specific incidence and mortality were relatively low among age groups under 0 years but dramatically increased and peaked in the 80-8 years old group. These findings confirm that liver cancer is a common and fatal cancer in China. Primary and secondary prevention such as health education, hepatitis B virus vaccination, and early detection should be carried out both in males and females, in urban and rural areas. Key words Liver cancer, cancer registry, incidence, mortality, China Liver cancer is a common and fatal cancer in the world. According to world cancer statistics, 79,000 new cases were diagnosed and 695,000 deaths were reported in 2008 [1]. In China, liver cancer has been the second leading cause of cancer death since the 19s [1]. Time trend analysis showed that the crude incidence of liver cancer is increasing, and a slight downward trend has been observed over the last 20 years after adjusted by age. The National Central Cancer Registry (NCCR) of China is the government organization in charge of collecting cancer information nationwide and reporting cancer statistics annually. Since 2008, the Chinese National Office for Cancer Prevention and Control & National Cancer Center, Beijing 100021, P. R. China. Wan 鄄 Qing Chen, National Office for Cancer Prevention and Control & National Cancer Center, Beijing 100021, P. R. China. Tel: +86 鄄 10 鄄 8778709; Fax: +86 鄄 10 鄄 67718227; Email: chenwq@ cicams.ac.cn. 10.572/cjc.01.10027 Cancer Registry annual report has provided cancer incidence and mortality data with which to create strategies for cancer prevention and control. In 2012, NCCR collected data for the calendar year of 2009 from 10 registries. After comprehensive quality control, data from 72 registries were accepted as sources of the annual report to reflect cancer incidence and mortality in the registration areas in 2009. In this study, liver cancer cases were retrieved from the national database for analysis. Materials and Methods Data source All new cancer cases diagnosed in 2009 were reported to local cancer registries from all hospitals, community health centers, and the other departments, including centers of township medical insurance and the New type Cooperative Medical System. Vital 162 www.cjcsysu.com CACA Chinese Anti 鄄 Cancer Association
statistics were linked and matched with the cancer registration database for identifying cancer deaths and missed cases. For all 10 cancer registries (6 cities and 58 counties from 27 provinces) reporting cancer registration data to NCCR, the overall population coverage was,76,7, accounting for 8.20% of the whole population in 2009. The cancer registries coded cancer site and histology according to the International Classification of Diseases for Oncology, third edition (ICD 0) and tenth edition (ICD 10). Invasive cases of liver cancer (topography code as C22) were retrieved from the NCCR database and analyzed. Demographic information was provided by the National Statistics Bureau. Quality control Based on 野 Guideline of Chinese Cancer Regis 鄄 tration 冶 and the standard of data inclusion in 野 Cancer Incidence in Five Continents Volume IX 冶 [2], cancer registration data were evaluated by the following quality indicators: proportion of morphologic verification (MV% ), percentage of cancer cases identified with death certification only (DCO%), and mortality to incidence ratio (M/I) [ 5]. The detailed standard for data inclusion was shown previously [6]. Generally, data with DCO% less than 20%, overall MV% more than %, and M/I between 0. and 0.95 were considered acceptable. Statistical analysis Crude incidence and mortality of liver cancer were calculated by sex, area, and for 19 total age groups (<1, 1, 5 9, 噎 80 8, 逸 85 years). Age standardized rates were calculated using the Chinese population in 1982 and Segi (world) population. The cumulative risk of deve 鄄 loping or dying from cancer before 75 years of age (in the absence of competing causes of death) was calculated and presented as a percentage. Software including MS FoxPro, MS Excel, and IARCcrgTools issued by International Agency for Research on Cancer (IARC) and International Association of Cancer Registry (IACR) were used for data checkup. SAS software was used to calculate the incidence and mortality rates. Results Pooled data Data from 72 population based cancer registries were accepted for the annual report after evaluation based on quality control criteria. The population covered by these cancer registries was 85,70,522, including,21, males and 2,28,968 females, accounting for 6.0% of the whole national population. A total of 1 registries were from urban areas, covering a total population of 57,89,009, and 1 registries were from rural areas, covering a total population of 27,981,51. The MV%, DCO%, and M/I of liver cancer for the national pooled data were.10%, 5.91%, and 0.91, respectively. The MV%, DCO%, and M/I were 8.11%, 6.08%, and 0.91, respectively, in urban areas and 27.6%, 5.6%, and 0.91, respectively, in rural areas. There were 2,5 new cases of liver cancer (18,1 males and 6,81 females) and 22,2 liver cancer deaths (16,09 males and 5,86 females) in 2009. Population and liver cancer incidence and deaths in each cancer registry are shown in Table 1. Incidence The crude incidence of liver cancer was 28.71/100,000 in 2009, accounting for 10.0% of overall new cancer cases and ranking fourth in all cancer sites. The age standardized incidences by the Chinese population (ASIRC) and world population (ASIRW) were 1.78/100,000 and 19.28/100,000, respectively. Among persons under the age of 75, the cumulative incidence was 2.20%. Liver cancer occurred more often in males than in females. For males, liver cancer was the third most common cancer, with a crude incidence of 1.99/ 100,000, whereas the ASIRC and ASIRW were 22.9/ 100,000 and 29.17/100,000, respectively. For females, liver cancer was the fifth most common cancer, with a crude incidence of 15.11/100,000, whereas the ASIRC and ASIRW were 7.11/100,000 and 9.52/100,000, respectively. The crude incidence in urban areas (26.6/ 100,000) was lower than that in rural areas (2.98/ 100,000) but ranked fourth in both areas. After age standardization, the incidence in urban areas (ASIRW = 17.18/100,000) was still lower than that in rural areas (ASIRW = 2.0/100,000) (Table 2). The age specific incidence was relatively low in subjects under 0 years old but dramatically increased in those over 0, peaking in the 80 8 years old group in both males and females. Notably, after the age of 0, incidence in males was more than double that in females, although there were slight differences among those under 0. The age specific liver cancer incidence in urban areas was generally lower than that in rural areas both in males and females, especially in older age groups (Table, Figure 1). Mortality The crude mortality for liver cancer was 26.0/ 100,000 in 2009, accounting for 1.2% of overall Chin J Cancer; 201; Vol. 2 Issue Chinese Journal of Cancer 16
Chin J Cancer; 201; Vol. 2 Issue www.cjcsysu.com Registry Area Population Beijing Qianxi Shexian Cixian Baoding Yangquan Yangcheng Chifeng Shenyang Dalian Zhuanghe An'shan Benxi Dandong Donggang Dehui Yanji Daoli District, Harbin Nangang District, Harbin Shangzhi Shanghai Jintan Suzhou Haian Qidong Haimen Lianyungang Donghai Guanyun Chuzhou District, Huai 忆 an Huaiyin District, Huai 忆 an Xuyi Jinhu Sheyang Jianhu Dafeng Yangzhong Taixing Hangzhou Jiaxing Jiashan Haining Shangyu Xianju Feixi Maanshan Tongling Changle Xiamen 7,65,186 1,12 9,9 6, 98,612 68,165 8,165 1,20,006,97,815 2,266,22 915,660 1,71,775 9,09 767,011 60,85 9,95 0,957 71,26 1,020,2 616,06 6,181,,000 2,92,087 9,785 1,11,951 1,016,228 886,862 1,117,858 1,015,229 1,17,877 0,027 759,50 52,292 965,817 805,65 72,17 272,06 1,128,80 6,75,509 509,7 82,75 65,957 771,21,070 858,895 6,77, 67,717 1,160,15,859,586 182,18 205,168 22,621 78,051 6,02 192,119 61,725 1,722,976 1,1,772 61,826 71,916 75,11 78,79 2,798 79,86 215,260 51,071 508,921 1,86,08,96 262,07 1,18,716 6,612 58,805 501,07 52,58 579,751 5,502 609,088 65,502 88,180 176,689 9,682 10,9,26 1,758 61,199,0,89 25,819 189,692 22,969 8,62 2,8 9,882 2,8 221,75,091 58,87,785,600 179,17 189,776 11,712 70,561 7,12 191,06 589,281 1,77,89 1,129,52 5,8 79,859 80,296 88,217 17,0 6,9 225,697 2,19 511,12 01,182,096,88 282,59 1,208,71 7,17 566,16 51,821,50 58,107 80,727 565,789,525 71,270 175,60 71,15 95,096 0,821 17,288 515,61,9,616 2,58 192,78 0,988 87,859 2,62 09,01 09,6 212,170 18,626 576,262 1,98 89 80 161 1 60 796 71 262 6 275 17 228 16 210 20 251 1,729 88 619 1 8 5 19 268 51 281 268 29 77 15 200 26 8 5 2,056 19 15 16 282 177 15 125 67 19 15 1,09 68 9 69 72 8 567 57 189 27 206 212 25 158 121 15 166 167 1,225 60 5 250 611 15 15 201 261 212 21 172 57 02 16 191 50 1,5 9 106 100 22 11 121 105 18 9 05 21 1 58 7 9 117 229 166 7 119 69 105 98 70 25 57 6 8 50 28 17 111 22 129 0 67 69 5 67 20 11 7 7 15 52 5 7 6 59 2 20 2 6 76 1,2 66 80 101 180 92 10 80 622 28 00 282 266 218 228 11 170 217 166 1,59 119 2 78 506 20 220 206 29 1 70 79 19 229 05 1,97 10 160 19 282 18 15 11 6 1 9 970 51 61 72 10 61 8 260 5 58 20 291 218 195 157 157 121 16 111 1,151 85 78 27 569 7 1 168 2 152 197 10 60 270 158 172 1 15 1,0 92 217 19 11 7 12 5 15 19 29 76 1 6 95 21 16 81 6 71 61 71 28 9 5 2 167 95 21 1 9 52 78 5 52 50 10 57 1 5 0 51 7 65 1 2 17 0 81 New cancer cases Cancer death (To be continued) Wan 鄄 Qing Chen et al. 16
Registry Area Population New cancer cases Cancer death Zhanggong District, Ganzhou Linqu Wenshang Feicheng Yanshi Linzhou Xiping Wuhan Yunmeng Hengdong Guangzhou Sihui Zhongshan Liuzhou Fusui Jiulongpo District, Chongqing Qingyang District, Chengdu Ziliujing District, Zigong Yanting Jingtai Liangzhou District, Wuwei Xining Xinyuan Total 20,759 817,857 762,828 7,501 602,266 1,080,21 858,002,82,17 52,801 71,58,968,216 1, 1,68,91 1,08,208,2 798,618 5,701 57,600 610, 2,609 9,58 882,89 271,9 85,70,522 212,159 17, 88,5 58,79 06,192 7,92,899 2,8,622 261,27 7,92 2,01,580 211,51 72, 5,050 2,000 02,961 277,15 179,87 16,99 119,95 52,276 9,175 18,895,21, 208,600 00,2 7,7 7,762 296,07 522,89 2, 2,7,2 26,56 9,55 1,95,6 202,012 7,058 505,158 208,2 95,657 257,57 177,727 29,60 11,656 66,07,66 1,09 2,28,968 17 21 11 175 119 17 279 1,211 1 25 1,20 16 7 11 19 120 18 16 61 182 215 66 2,5 15 1 85 12 81 98 189 9 105 179 1,0 127 288 277 256 117 21 8 128 11 8 18,1 29 71 29 52 8 9 278 50 56 277 7 70 2 0 29 2 5 7 18 6,81 18 210 15 11 100 19 25 91 188 19 1,22 10 00 250 29 189 107 101 280 5 297 129 5 22,2 110 157 112 101 6 96 17 722 1 11 951 250 197 195 15 8 78 1 210 89 16,09 8 5 1 0 80 219 291 1 50 5 2 2 18 87 0 17 5,86 Location Sex No. of cases Crude incidence (1/10 5 ) Percentage (%) ASIRC (1/10 5 ) ASIRW (1/10 5 ) Cumulative rate (%) Age 0-7 Rank a All areas 2,5 18,1 6,81 15,07 11,25,882 9,229 6,70 2,99 28.71 1.99 15.11 26.6 9.2 1.62 2.98 7.2 18.19 10.0 1.21 5.97 8.78 11.9.9 1.19 16.12 8.86 1.78 22.9 7.11 1.1 20.2 6.05 18.52 27. 9.57 19.28 29.17 9.52 17.18 26. 8.15 2.0 5.26 12.70 2.20.1 1.11 1.95 2.98 0.9 2.77.0 1.8 5 5 5 a The proportion rank of liver cancer in all cancer types. ASIRC, age 鄄 standardized incidence by Chinese population; ASIRW, age 鄄 standardized incidence by world population. cancer deaths in 2009. The ASMRC and ASMRW for mortality were 1.06/100,000 and 17.26/100,000, respectively. Among patients at 0 7 years of age, the cumulative mortality was 1.96%. The mortality was higher in males than in females. The crude mortality, ASMRC, and ASMRW were 7.96/100,000, 19.91/100,000, and 26.1/100,000, respectively, for males and 1.8/100,000, 6.28/100,000, and 8.5/100,000, respectively, for females. These values were 2.15/100,000, 11.51/100,000, and 15.27/100,000, respectively, in urban areas and 29.91/100,000, 16.5/100,000, and Chin J Cancer; 201; Vol. 2 Issue Chinese Journal of Cancer 165
Age group All areas areas areas All 0-1- 5-10- 15-20- 25-0- 5-0- 5-50- - 60-65- 70-75- 80-85- 28.71 1.1 0. 0.1 0.18 0.1 0.7 1.5 5.18 11.51 21.82 0.81 9.50 60.65 71.62 8.2 101.76 121.72 1.99 119. 1.99 1.5 0. 0.16 0.17 0.57 0.87 2.66 8.9 19.82.1 50.0 79. 95.18 106.20 119.88 10.1 16.58 182.7 165.76 15.11 0.68 0.1 0.12 0.18 0.0 0.59 0.7 1.91.10 7.02 10.50 18.51 25..9 9. 66.9 8.6 95.0.12 26.6 1.0 0.65 0.1 0.2 0.28 0.61 1..7 9.5 17. 27.57 2.9 52.96 6.7 75.07 92.66 11.57 11.10 119.0 9.2 1.99 0. 0.18 0.22 0. 0.78 2.19 7.79 16.9 0.28 6.27 70.06 85.51 96.5.9 127.1 1.97 180.85 166.5 1.62 0. 0.7 0.10 0.2 0. 0.5 1.65 2.51 5.29 8.09 1.20 20.77 1.06 1.97 61.5 77..66 88. 2.98 0.85 0.10 0.1 0.10 0.7 1.02 1.98 5.97 15.5 29.69 8.12 67. 79.0 89.2 102.52 12.65 10.27 11.29 120.8 7.2 0.79 0.1 0.10 0.61 1.10.72 9.7 26.1 8.7 59.76.7 117.58 126.0 18.87 170.9 187.5 187.76 16.1 18.19 0.91 0.21 0.1 0.11 0.11 0.9 0.18 2.0.28 10.51 15.89 29.59 8.52 50.10 6.95 78.76 99.6 106.61 9.6 All values are presented as incidence (1/100,000). 200 180 160 10 120 100 80 60 0 20 0 males females males females 20-25- 0-5- 0-5- 50- - 60-65- 70-75- 80-85- Age (years) Figure 1. The age 鄄 specific incidence kept increasing with the age increase and reached at peak in the 80-8 years old group. Incidences in rural areas were higher than those in urban areas and incidences in males were higher than those in females in any age group. 21.72/100,000, respectively, in rural areas. Liver cancer was ranked the second leading cause of cancer death in urban and third in rural areas (Table, Figure 2). Mortality was relatively low in age groups under 5 166 www.cjcsysu.com Chin J Cancer; 201; Vol. 2 Issue
Location Sex No. of cases Crude mortalty (1/10 5 ) Percentage (%) ASMRC (1/10 5 ) ASMRW (1/10 5 ) Cumulative rate (%) Age 0-7 Rank a All areas 22,2 16,09 5,86 1,885 10,268,617 8,70 6,11 2,229 26.0 7.96 1.8 2.15 5. 12.69 29.91.11 16.2 1.2 16.9 10.19 1.28 15.85 9.09 16.82 19.10 12.66 1.06 19.91 6.28 11.51 17.76 5.9 16.5 2.65 8. 17.26 26.1 8.5 15.27 2.0 7.8 21.72 2.17 11.22 1.96 2.95 0.99 1.72 2.62 0.8 2.50.66 1.2 2 2 2 2 a The proportion rank of liver cancer in all cancer types. ASMRC, age 鄄 standardized mortality by Chinese population; ASMRW, age 鄄 standardized mortality by world population. 250 200 150 100 500 0 males females males females 20-25- 0-5- 0-5- 50- - 60-65- 70-75- 80-85- Age (years) Figure 2. The age 鄄 specific mortality kept increasing with the age increase and reached at peak in the 80-8 years old group except for urban females. Mortalities in rural areas were higher than those in urban areas and mortalities in males were higher than those in females in any age group. and peaked in the 80 8 year old age group in overall areas and urban areas. In rural areas, mortality in the over 85 age group was the highest among all age groups. After the age of 15, age specific mortality was higher in rural areas than in urban areas and was higher in males than in females (Table 5). Discussion For this analysis of liver cancer incidence and mortality, we assessed data from 72 cancer registries covering 85.7 million people from 27 provinces 要 the largest population coverage since NCCR started to publish annual reports in 2008. We found that there were 2,5 new cases and 22,2 deaths from liver cancer. Although a large sample size was included in this study, further representative analysis should follow. In terms of quality control, morphologic verification for liver cancer is relatively low compared with other cancers, especially in rural areas, because medical resources are limited and pathologic examination cannot always be performed (e.g., for late stage liver cancer). In global data, the MV% of liver cancer fluctuated markedly among different countries and registries [7]. The national cancer registry program was established by the Ministry of Health in 2008, providing grants from central finance to build a national cancer registry network. The number of cancer registries has increased from in 2007 to 222 in 2012, with the covered population reaching 200 million. It is estimated that there will be more than 00 registries covering 20% of the national population by the end of 2015. Chin J Cancer; 201; Vol. 2 Issue Chinese Journal of Cancer 167
Age group All areas areas areas All 0-1- 5-10- 15-20- 25-0- 5-0- 5-50- - 60-65- 70-75- 80-85- 26.0 0.8 0.7 0.08 0.0 0.2 0.57 1.02.27 8.80 17.8 26.9 1.98 51.61 6.8 78.18 99. 125. 1.15 1.80 7.96 0.61 0.2 0.11 0.0 0.9 0.7 1.6 5.6 1.89 29.21.15 67.95 82.20 95.1 111.1 1.8 172.50 200.7 187.58 1.8 0. 0.1 0.06 0.05 0.08 0.9 0.9 1.0 2.6 5.1 8.17 15.21 20.81 1.71 5.82 65.25 8.6 99.6 10.66 2.15 0.78 0.7 0.05 0.0 0.1 0.50 0.88 2.68 7.50 1. 2.65.17.50 5.98 68.96 91.8 119.9 1.2 1.6 5. 1.00 0.68 0.09 0.07 0.28 0.67 1.29.5 12.62 22.86 0.19 60.0 72.82 82. 100.01 126.22 16.05 202.21 18.60 12.69 0. 0.25 0.2 0.5 0.80 2.5.07 6.1 11.69 16.51 26.11 9.9 60.09 80.22 95.62 102.21 29.91 0.19 0.1 0.05 0.2 0.7 1.5.2 11.8 25.09 2. 56.77 68.59 8.99 96.5 118. 11.18 16.01 12..11 0.1 0.61 0.92 2.9 7.12 19.8 1.9 5.12 87..95 121.59 12.88 160.1 197.50 195.86 195.81 16.2 0.1 0.1 0.11 0.22 0.56 0.27 1.6.21 7.80 12.12 2.2 1..29 58.97 78.00 92. 108.81 110.8 All values are presented as mortality (1/100,000). Compared with the results in 2008 [8], the crude incidence and mortality fluctuated slightly in 2009 due to different population coverage. However, after adjusting for age, the rates remained stable, reflecting the good quality of the registration data [6]. Chen. reported that there were 9,000 incident cases of liver cancer in China in 2005 [9] and predicted that number would reach 81,000 in 2020 [10]. Recent trend analysis showed that although age adjusted incidence has decreased, the liver cancer burden is increasing [11]. China is a high risk region for liver cancer, representing more than half of new cases and liver cancer deaths in the world [12]. Since high risk areas like Qidong in Jiangsu province implemented hepatitis B virus (HBV) vaccination for children, the HBV infection rate has fallen, reducing the incidence of liver cancer in the young generation. Early in the 21st century, when expanded program immunization was carried out in China, hepatitis B was effectively controlled, providing a benefit for liver cancer control [1,1]. In Qidong, liver cancer screening programs were introduced in 2006 [15]. Similarly, some high risk areas gradually started early detection and treatment for liver cancer. HBV vaccination and screening as well as health education and promotion have become areas of focus for high risk areas in China. In conclusion, although the incidence of liver cancer has started to decrease in most age groups, especially in the young generation, it is still a major public issue in China. The cancer registry provides timely and dynamic information for making national, regional, and local policies for cancer control. As NCCR continues to expand the national cancer registry system, primary and secondary prevention of liver cancer is expected to improve. Acknowledgments We thank all staff from local cancer registries for providing access to their registration databases. Received: 201 02 0; revised: 201 02 16; accepted: 201 0 05. References 咱 1 暂 Ferlay J, Shin HR, Bray F, et al. Estimates of worldwide burden of cancer in 2008: Globocan 2008. Int J Cancer, 2010,127:289-2917. 咱 2 暂 Chen WQ, Zhang SW, Zou XN, et al. An analysis of lung cancer mortality in China, 200-2005. Zhonghua Yu Fang Yi Xue Za Zhi, 2010,:78-82. [in Chinese] 168 www.cjcsysu.com Chin J Cancer; 201; Vol. 2 Issue
咱 暂咱 暂咱 5 暂咱 6 暂咱 7 暂咱 8 暂咱 9 暂 Chen JG, Zhang SW. Liver cancer epidemic in China: past, present and future. Semin Cancer Biol, 2011,21:59-69. Curado M, Edwards B, Shin H, et al. Cancer incidence in five continents. Volume ix. Lyon, France: International Agency for Research on Cancer, 2008. Parkin DM. Comparability and quality control in cancer registration. Lyon, France: International Agency for Research on Cancer, 199. Ferlay J, Burkhard C, Whelan S, et al. Check and conversion programs for cancer registries. Lyon, France: International Agency for Research on Cancer, 2005. National Office for Cancer Prevention and Control, National Center for Cancer Registry, Disease Prevention and Control Bureau, MOH. Chinese cancer registry annual report (2010). Beijing: Military Medical Science Press, 2011:2. Ferlay J. International Agency for Research on Cancer. International Association of Cancer Registries. CI5VII electronic database of cancer incidence in five continents, Vol. vii. IARC cancerbase No. 2 Lyon, France: International Agency for Research on Cancer, 1997. Chen WQ. Estimation of cancer incidence and mortality in China in 200-2005. Zhonghua Zhong Liu Za Zhi, 2009,1: 66-668. [in Chinese] 咱 10 暂咱 11 暂咱 12 暂咱 1 暂咱 1 暂咱 15 暂 Chen W, Zhang S, Zou X. Estimation and projection of lung cancer incidence and mortality in China. Zhongguo Fei Ai Za Zhi, 2010,1:88-9. [in Chinese] Chen W, Zhang S, Zou X. Evaluation on the incidence, mortality and tendency of lung cancer in China. Thoracic Cancer, 2010,1:8-5. Ferlay J SH, Bray F, Forman D, et al. GLOBCAN 2008 v1.2, cancer incidence and mortality worldwide: LARC CancerBase No. 10 [Internet]. Lyon, france: International agency for research on cancer; 2010. Available from: http://globocan.iarc. Fr, accessed on 1/8/2011. Chen JG, Lu JH, Zhu YR, et al. A thirty 鄄 one year prospective follow 鄄 up program on the hbsag carrier state and primary liver cancer in Qidong, China. Zhonghua Liu Xing Bing Xue Za Zhi, 2010,1:721-726. [in Chinese] Chen JG, Zhu J, Zhang YH, et al. Evaluation of secular trend of liver cancer incidence in Qidong, Jiangsu province, 197-2002. Zhonghua Yi Xue Za Zhi, 2005,85:052-056. [in Chinese] Chen JG, Parkin DM, Chen QG, et al. Screening for liver cancer: results of a randomised controlled trial in Qidong, China. J Med Screen, 200,10:20-209. Chin J Cancer; 201; Vol. 2 Issue Chinese Journal of Cancer 169