Cancer Incidence and Mortality in Zhejiang Province, Southeast China, 2016: A Population-Based Study
Introduction
Cancer remains one of the leading causes of death worldwide, posing a significant threat to human health and life expectancy. Understanding the burden of cancer through population-based cancer registration is essential for developing effective prevention and control strategies. Zhejiang Province, located on the southeastern coast of China, is one of the country’s most economically developed regions. The Zhejiang Provincial Office for Cancer Prevention and Control has been responsible for cancer registration and the public release of cancer incidence and mortality data. This study aims to analyze the cancer incidence and mortality rates in Zhejiang Province in 2016, providing a comprehensive overview of the cancer burden in the region.
Methods
Data for this study were collected from 14 population-based cancer registries across Zhejiang Province, covering a population of 14,250,844 individuals, which represents approximately 29.13% of the province’s total population. The registries included five urban areas (Hangzhou, Yinzhou, Lucheng, Jiaxing, and Shangyu) and nine rural areas (Cixi, Jiashan, Haining, Changxing, Yongkang, Kaihua, Daishan, Xianju, and Longquan). Data were obtained from hospitals, community health centers, and linked with the All-Death Surveillance System to identify cases with death certificates only (DCO) and passive follow-ups.
The data quality was evaluated based on the proportion of morphological verification (MV%), the percentage of cancer cases identified through death certificates only (DCO%), the mortality-to-incidence ratio (M/I ratio), and the percentage of the diagnosis of unknown basis (UB%). The incidence and mortality rates were stratified by sex, age, and region. The crude rate, age-standardized rate, age-specific and region-specific rate, and cumulative rate were calculated. The Chinese national census of 2000 and the world Segi population were used for calculating the age-standardized incidence and mortality rates.
Results
Incidence
In 2016, there were 55,835 new cancer cases reported in Zhejiang Province, with 29,433 cases in men and 26,402 cases in women. The crude incidence rate was 391.80 per 100,000 population (414.48 per 100,000 in men and 369.28 per 100,000 in women). The age-standardized incidence rate by the Chinese standard population (ASIRC) was 229.76 per 100,000, and the age-standardized incidence rate by the world standard population (ASIRW) was 220.96 per 100,000. The cumulative incidence rate for individuals aged 0 to 74 years was 24.86%.
The incidence rate in men was 1.12 times higher than that in women, and the rate in urban areas was higher than in rural areas. The cancer incidence rate increased sharply after the age of 45 and peaked in individuals aged 80 to 84 years (1579.37 per 100,000). The top 10 most common cancers in Zhejiang Province were lung cancer, female breast cancer, thyroid cancer, colorectal cancer, stomach cancer, liver cancer, prostate cancer, cervical cancer, esophageal cancer, and pancreatic cancer.
Mortality
There were 27,013 cancer deaths in 2016, with 17,676 deaths in men and 9,337 deaths in women. The crude mortality rate was 189.55 per 100,000 population (248.91 per 100,000 in men and 130.59 per 100,000 in women). The age-standardized mortality rate by the Chinese standard population (ASMRC) was 94.46 per 100,000, and the age-standardized mortality rate by the world standard population (ASMRW) was 93.42 per 100,000. The cumulative mortality rate for individuals aged 0 to 74 years was 10.28%.
The mortality rate in men was 1.91 times higher than that in women, and the rate in rural areas was higher than in urban areas. The cancer mortality rate increased sharply after the age of 50 and peaked in individuals aged 85 years and older (1430.74 per 100,000). The top 10 leading causes of cancer death were lung cancer, liver cancer, stomach cancer, colorectal cancer, pancreatic cancer, esophageal cancer, female breast cancer, prostate cancer, lymphoma, and leukemia.
Age-Specific and Region-Specific Rates
The cancer incidence rate increased with age, with a sharp rise after 45 years and a peak in the 80-84 age group. The mortality rate also increased with age, peaking in individuals aged 85 years and older. In urban areas, the incidence rate was higher than in rural areas, while the mortality rate was higher in rural areas compared to urban areas.
Among the 14 cancer registries, Daishan had the highest crude incidence rate (597.37 per 100,000) and the highest crude mortality rate (292.22 per 100,000). After age standardization, Jiashan had the highest ASIRC (274.79 per 100,000), and Daishan had the highest ASIRW (282.88 per 100,000). In terms of mortality, Daishan also had the highest ASMRC (122.35 per 100,000), and Changxing had the highest ASMRW (121.76 per 100,000).
Top Cancers by Age Group
Leukemia was the most common cancer in children aged 0 to 14 years, with an incidence rate of 4.86 per 100,000. In the 15-44 age group, thyroid cancer was the most common, with an incidence rate of 46.02 per 100,000. Female breast cancer was the most common in the 45-64 age group, with an incidence rate of 106.66 per 100,000. In individuals aged 65 years and older, lung cancer was the most common, with an incidence rate of 313.27 per 100,000.
Brain cancer was the leading cause of cancer death in children aged 0 to 14 years, with a mortality rate of 1.64 per 100,000. In the 15-44 age group, liver cancer was the leading cause of death, with a mortality rate of 2.88 per 100,000. Lung cancer was the leading cause of death in the 45-64 age group, with a mortality rate of 47.27 per 100,000, and in individuals aged 65 years and older, with a mortality rate of 270.05 per 100,000.
Discussion
The findings of this study highlight the significant burden of cancer in Zhejiang Province, with lung cancer, female breast cancer, thyroid cancer, colorectal cancer, prostate cancer, liver cancer, and stomach cancer being the most common cancers. The incidence and mortality rates were higher in men than in women, and the rates increased sharply with age, particularly after 45 years. The cancer spectrum in Zhejiang Province shows characteristics of both developing and developed countries, with a high incidence of digestive system cancers and increasing rates of prostate and thyroid cancers.
The higher incidence and mortality rates in rural areas compared to urban areas suggest disparities in healthcare access and cancer awareness. Efforts to improve cancer prevention and control should consider these regional differences, with a focus on early diagnosis and treatment in urban areas and improving access to care and reducing mortality in rural areas.
The study also underscores the importance of cancer registration in understanding the cancer burden and guiding public health interventions. The data quality indicators, including MV%, DCO%, and M/I ratio, indicate that the cancer registration system in Zhejiang Province is robust and reliable. Continued efforts to expand and improve cancer registration will be essential for monitoring cancer trends and evaluating the effectiveness of prevention and control measures.
Conclusion
This study provides a comprehensive analysis of cancer incidence and mortality in Zhejiang Province in 2016, highlighting the significant burden of cancer and the need for targeted prevention and control strategies. The findings underscore the importance of addressing regional disparities and focusing on high-risk populations, particularly the elderly and those in rural areas. Effective cancer prevention and control measures, informed by reliable cancer registration data, will be essential for reducing the cancer burden in Zhejiang Province and improving public health outcomes.
doi.org/10.1097/CM9.0000000000001666
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