| Cancer is one of the major non-communicable diseases threatening human life and health seriously.According to the estimate of International Agency for Research on Cancer(IARC),more than 14.1 million new cancer cases and 8.2 million cancer deaths occurred in 2012 globally,making cancer a leading cause of death in the worldwide.In China,cancer is also one of the major public health problems.With increasing incidence and mortality,cancer has become the leading cause of death since 2010.Because of ageing populations,contamination of the environment and increasingly westernized lifestyles,the cancer incidence and mortality may continue to show an upward trend in China in the next few decades.Cancer has posed a threat to Chinese health and brought an enormous burden on society.Thus,comprehensive and accurate information of cancer prevalence can provide scientific basis for cancer prevention and control strategies.Since 2008,National Center of Cancer Registration(NCCR)has regularly published an annual report on status of cancer in China,providing reliable data for cancer prevention and control strategies nationwide.At the end of 2015,there were 416 cancer registries covering about 430 million people and 25%of the Chinese population.With the expanding coverage of cancer registries,the representative and quality of the cancer registration data have been improved rapidly.Meanwhile national Center of Cancer Registration uses the registration data to estimate the cancer incidence and mortality and find out cancer epidemiological traits.It has played an important role in cancer research,prevention and control.However,there are still some deficiencies in cancer registration data,such as data representative and quality.Results on cancer incidence and mortality from nationwide prospective cohort could be an important supplementary to cancer registration.The China Kadoorie Biobank study(CKB)was established in 2004,launched by the Chinese Academy of Medical Sciences and the University of Oxford.The China Kadoorie Biobank study,a large prospective cohort studies,aims to investigate the effects of genetic,environmental and lifestyle aspects on pathogenesis and development of major chronic diseases(such as cancer)in China.Cohort studies have been able to obtain more accurate incidence and mortality information because of their own research design advantages,such as follow-up.In this study,we estimate the cancer incidence and mortality from the China Kadoorie Biobank study large prospective cohort data,comparing with China cancer registration data,to explore the prevalence of cancer in Chinese population and to provide scientific basis for cancer prevention and control.In this study,we use the China Kadoorie Biobank study cohort data.The study took place in 5 urban and 5 rural areas across China and only recruited permanent residents in each area.Finally,a total of 512891 participants aged 30-79 years recruited and successfully followed up by Disease Surveillance Points(DSP)system,disease registries and national health insurance from 2004 to 2013.Diseases were coded by 10th International Classification of Diseases(ICD-10)and causes of death were from official death certificates.For this study,we only select those participants who were cancer free in the recruitment and aged 35-74 years.A total of 497693 participants were included in this cancer incidence and mortality study.Cancer incidence and mortality rates were presented as per 100 000 person years(PY)in this study.The crude incidence and mortality rates were standardized by age,sex,and region(urban/rural)using the population composition of those aged 35-74 years from the 2010 Chinese census population.For each cancer,we calculated the incidence and mortality rates to compare the difference between cancers.The median-cubic-spline,which calculates cross medians and then fits a cubic spline,was used to fit the incidence trend among different age groups for female-specific cancers.The mortality-to-incidence ratio(MIR)was also calculated to compare the difference of cancer burden between urban and rural areas.We compared our results with the 2010 Annual Report by the NCCR to discuss the prevalence of cancers in China.A total of 17 088 new cancer cases and 8052 cancer deaths were diagnosed before 31 December 2013.During 2004-2013,the crude incidence rate of all cancers among 10 regions across China was 483.69 per 100 000 PY.After standardization by age,sex,and region,the incidence rate was 452.69 per 100 000 PY,(517.22 in males,387.33 in females).The standardized cancer standardized incidence rates were 467.80 in urban areas and 446.47 in rural areas per 100 000 PY.The crude mortality rate was 225.90 per 100 000 PY.After standardization by age,sex,and region,the standardized mortality rate was 225.09 per 100 000 PY,(297.96 in males,150.36 in females).The standardized cancer mortality rates were 183.47 in urban areas and 241.22 in rural areas per 100 000 PY.Lung cancer,breast cancer,stomach cancer,esophageal cancer,liver cancer,colorectal cancer,cervix uteri cancer,pancreas cancer,lip-oral cavity and pharynx cancer and leukemia were the ten most frequently diagnosed cancers among Chinese.The cancer incidence was different between males and females.Among males,the ten most frequently diagnosed cancers were lung cancer,stomach cancer,esophageal cancer,liver cancer,colorectal cancer,lip-oral cavity and pharynx cancer,pancreas cancer,leukemia,bladder cancer and lymphoma.Among females,breast cancer,lung cancer,colorectal cancer,cervix uteri cancer,stomach cancer,esophageal cancer,liver cancer,ovary cancer,pancreas cancer and leukemia were the ten most common cancers.The leading causes of cancer death among Chinese were lung cancer,liver cancer,stomach cancer,esophageal cancer,colorectal cancer,pancreas cancer,breast cancer,cervix uteri cancer,leukemia and lymphoma.The cancer mortality between males and females was similar.Lung cancer,liver cancer,stomach cancer,esophageal cancer,colorectal cancer,pancreas cancer,lip-oral cavity and pharynx cancer,leukemia,lymphoma and prostate cancer were the leading causes of cancer death among males.Among females,lung cancer,liver cancer,stomach cancer,esophageal cancer,colorectal cancer,breast cancer,pancreas cancer,cervix uteri cancer,leukemia and ovary cancer were the leading causes of cancer death.There were significant differences in the incidence of cancers in urban and rural areas.Breast cancer,lung cancer,colorectal cancer,stomach cancer,liver cancer,cervix uteri cancer,esophageal cancer,ovary cancer,lip-oral cavity and pharynx cancer and endometrium cancer were the ten most frequently diagnosed cancers among urban areas.Lung cancer,esophageal cancer,stomach cancer,liver cancer,breast cancer,colorectal cancer,cervix uteri cancer,pancreas cancer,leukemia and lip-oral cavity and pharynx cancer were the ten most frequently diagnosed cancers among rural areas.The most commonly diagnosed cancer in urban areas,such as breast cancer and colorectal cancer,were only the fifth and sixth most common in rural areas.In contrast,esophageal cancer,which was the second most frequently diagnosed cancer in rural areas,ranked only seventh in urban areas.The cancer mortality between urban and rural areas was quite similar.The leading causes of cancer death among urban areas were lung cancer,liver cancer,stomach cancer,colorectal cancer,esophageal cancer,breast cancer,pancreas cancer,ovary cancer,leukemia and prostate cancer.The leading causes of cancer death among rural areas were lung cancer,liver cancer,esophageal cancer,stomach cancer,colorectal cancer,pancreas cancer,cervix uteri cancer,breast cancer,leukemia and lymphoma.Lung cancer and liver cancer were top two deadly cancers both in urban and rural areas.Esophageal cancer,stomach cancer and colorectal cancer also had high mortality rates in urban and rural areas.The MIR of all cancers in rural areas was 0.54,which was 38.46%higher than that in urban areas with 0.39.Compared with those in urban areas,the MIRs of the top ten common cancers were consistently higher in rural areas.This was especially obvious for female breast cancer,stomach cancer,colorectal cancer,and cervical cancer,which all showed at least a 20%increase in rural areas.Pancreas cancer had the highest MIR(0.78 in all people)among all the 15 cancers,followed by liver and lung cancer,while breast cancer had the lowest MIR.The median-cubic-spline was used to fit the incidence trend among different age groups for female-specific cancers.As expected,we observed a bimodal age distribution for breast cancer,cervix uteri cancer,and ovarian cancer.Compared to the results from the 2008-2012 Annual Report by the NCCR,which were mainly based on cancer registry system of China,the standardized cancer incidence was much higher in our data,while the mortality rate was almost equal.The age-specific analyses showed that the cancer incidence curves from the two sources were almost parallel but with an obvious upward offset of our data.However,the mortality curves generated from our data almost perfectly coincided with those from the NCCR.In this study,we performed a comprehensive analysis on the incidence and mortality of cancer in China based on the nationwide,prospective cohort-CKB.We found that lung cancer,stomach cancer,liver cancer,colorectal cancer,esophageal cancer and breast cancer were the most frequently diagnosed cancers and the leading causes of cancer death among Chinese.We observed that the standardized incidence rates of all cancers were almost comparable between urban and rural areas,while the standardized mortality rates were relatively higher in rural areas.The MIR of all cancers in rural areas was higher than that in urban areas,which indicates that the medical care and health awareness were quite different in urban and rural areas of China.The cancer profiles were different between urban areas and rural areas.In urban areas,the cancer profiles of China were transiting to Western distributions,which were characterized by higher incidence rates of lung cancer,breast cancer and colorectal cancer.Unlike urban cancer profiles,it is needed to point out that tumors in upper digestive system(e.g.stomach cancer,liver cancer,and esophageal cancer),remain keeping at high incidence rate in rural China.Compared to the results from the 2008-2012 Annual Report by the NCCR,which were mainly based on cancer registry system of China,the standardized cancer incidence was much higher in our data,while the mortality rate was almost equal.This suggested that cancer incidence rates in China were probably underestimated by the traditional cancer registry system,while the mortality rates were relatively credible.In summary,we found that the burden of cancer was still huge in China.Lung cancer,stomach cancer,liver cancer,colorectal cancer,esophageal cancer and breast cancer still needed to pay enough attention to.Considering the different cancer incidence and mortality,different cancer control strategies should be taken into account for urban and rural areas in the future. |
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