4 February 2023 marks the 24th World Cancer Day.
According to the World Health Organization, one in five people worldwide will develop cancer in their lifetime, and cancer prevention has become one of the greatest public health challenges of the 21st century.
Since 1974, China has carried out three national retrospective surveys of deaths focusing on tumors. Combined with the latest release of China's tumor registration annual report, the surging news reporter tried to interpret the changes in cancer (malignant tumor) mortality among Chinese residents in the past 50 years.
The mortality rate of lung cancer has increased 9 times in the past 50 years
In the nearly 50 years of follow-up investigation of the causes of death of Chinese residents, cancer is one of the three most important causes of death in Chinese. In 2020, cancer accounted for 23.87% of all Chinese causes of death, second only to heart disease. This equates to 1 in 5 deaths from cancer.
Among the various types of cancer, lung cancer, liver cancer, gastric cancer, esophageal cancer and colorectal cancer are the five major cancers with the highest mortality rate among Chinese residents. Among them, lung cancer mortality rate increased the fastest, and the crude mortality rate in 2017 (regardless of population and other factors) increased by 9 times faster than in the 70s of the last century. In contrast, the crude mortality rate of liver cancer and gastric cancer in China in 2017 showed a downward trend compared with the three national causes of death surveys (1973-2005).
In terms of gender, the mortality rate of the five major cancers in men was higher than that of women in previous surveys. The most significant differences were in lung and liver cancer, where crude death rates were almost twice as high among men as in 2017. It is worth noting that the mortality rate of female breast cancer has shown a clear upward trend in recent years, and in 2017 it has become the fifth leading cause of cancer death among women.
Three types of cancer mortality rates became higher in rural areas than in urban areas
In addition to gender differences, the mortality rate of common cancers in China also varies between urban and rural areas.
The figure above is divided diagonally, with white areas showing higher rural mortality rates than urban cancers, and purple areas showing urban cancer having higher mortality rates than rural cancers. In 2017, compared with the 70s of the last century, the mortality rate of lung, liver and stomach cancer in China shifted from higher in urban areas to higher in rural areas. Colorectal cancer mortality rates shifted from higher in rural areas to higher in urban areas.
In urban areas, breast cancer and colorectal cancer are the main cancers with high mortality rates, and they are on the rise in recent surveys. In rural areas, esophageal, gastric and liver cancers are the main cancers with high mortality rates, and they are showing a downward trend in recent surveys.
Pan Zhan, deputy chief physician of the oncology department of Zhongshan Hospital affiliated to Xiamen University, pointed out in an analysis article published by Guangming.com (2022) that at present, Chinese cancer is characterized by a decline in "poor cancer" and an increase in "rich cancer".
In the past, the so-called "rich cancers" such as colorectal cancer and breast cancer, which were low in China and high in developed countries, showed a continuous upward trend. The onset of these cancers is quite related to the modern "rich" lifestyle, especially obesity, sedentary lack of exercise, mental stress, etc.
The so-called "poor cancers" with high incidence and poor prognosis in China, such as esophageal cancer, gastric cancer, liver cancer, etc., have decreased their mortality rates year by year. However, the decline is not significant, and it is still relatively high. This situation of coexistence of "poor cancer" and "rich cancer" has made it extremely difficult to prevent and treat cancer on the mainland.
In addition to the difference between urban and rural areas, there is also a high incidence of cancer mortality in China. For different cancer types, "high incidence" refers to the death rate of a certain type of cancer in the region that is 1.6 to 5 times higher than the national average. According to the results of the first national survey on the cause of death, experts took 39 districts in 18 provinces as samples with high incidence of cancer and conducted return visits.
Overall, the changes in mortality in some areas with high cancer incidence are in line with the overall trend in China. Among the four typical counties (cities) with high incidence of lung cancer, the mortality rate of lung cancer is increasing in three counties (cities). In the five typical counties (cities) with high incidence of esophageal cancer, the mortality rate of esophageal cancer decreased.
China's breast cancer mortality rate is lower than the global average
Global Burden of Disease (GBD) data from 1990 to 2019 show that the mortality rate of lung cancer and colon cancer in China has increased year by year, showing an increasing trend contrary to the world. Mortality rates from liver, stomach and esophageal cancers are consistent with global declines, but all are higher than the global average.
Of the six most common cancers in China, only breast cancer has a mortality rate below the global average, and the growth trend is stable. According to CCTV news reports, the overall 5-year survival rate of breast cancer patients in mainland China has exceeded 80%, and the 5-year survival rate of early-stage breast cancer in third-class hospitals in Beijing, Shanghai, Guangzhou and other cities has even reached more than 90%, which is basically the same as that of Western developed countries.
(The Paper reporter Chen Liangxian also contributed to this article)
Resources:
1. United Nations - New WHO Platform for Global Cancer Prevention, https://news.un.org/zh/story/2022/02/1098782
2. China Cause-of-Death Monitoring Data Set 2020, https://ncncd.chinacdc.cn/xzzq_1/202101/t20210111_223706.htm
3. 2020 China Cancer Registration Annual Report, People's Medical Publishing House
4, Guangming Network - "Poor cancer" falls, "rich cancer" rises... The latest cancer data has 4 characteristics", https://www.toutiao.com/article/7124831221934522910/
5. CCTV Network - "National Cancer Prevention and Treatment Publicity Week 420,000 new breast cancer patients in mainland China every year", https://tv.cctv.com/2022/04/15/VIDE7pMkdI3bdPNi0O8pzBym220415.shtml
6. Li Bing, Li Junyao - "Mortality and Distribution Characteristics of Malignant Tumors in China", Chinese Journal of Oncology, Vol. 2, No. 1, 1980
7. Li Liandi et al., "Analysis of the Epidemiological Distribution of Malignant Tumor Deaths in China in 1990~1992", Chinese Journal of Oncology, Vol. 18, No. 6, November 1996
8. Chen Zhu, ed., "National Three Causes of Death Review Sample Survey Report", Peking Union Medical College Press