In the past, estimates of the overall incidence of childhood cancer worldwide were based primarily on data from the Cancer Registry. However, 60% of countries in the world do not have such registrations, and if they do, they cover only a small portion of the total population. In addition, many patients have not been “documented” because they have not been diagnosed.
The micro-simulation model estimates and reports on the annual number of confirmed cases of childhood cancer worldwide. The authoritative cancer agency IARC estimates are similar (Source: The Lancet Oncology)
To provide an accurate estimate of the global incidence of childhood cancer, from Harvard University Chen Zengxi Public Health Five scientists from institutions such as the College have developed a global microscopic simulation model of childhood cancer that simulates the incidence of cancer among children (0-14 years) in 200 countries and regions around the world.
Model estimates, 2015, global children The number of cancer cases (new cases) was 397,000, of which only 224,000 were diagnosed. This indicates that in 2015, 43% (172,000) of the world's childhood cancer cases were not diagnosed, and the differences between the regions were very different. Big (Figure 1).
Figure 1. Number of total cancer cases and confirmed cases in children worldwide by 2015 (Source: The Lancet Oncology)
< Among them, undiagnosed cases in Western Europe and North America accounted for only 3% of the total number of new cases, while the proportion of undiagnosed cases in West Africa was as high as 57% (43000 of 76000).
Figure 2. Total predicted incidence and regional distribution of TOP15 cancer species in 2015 (Source: The Lancet Oncology)
From segmentation of cancer In 2015, except for sub-Saharan Africa, the most common childhood cancer in most parts of the world is acute lymphoblastic leukemia (ALL), with approximately 75,000 new cases worldwide, including nearly 700 in Northern Europe. West Africa Nearly 1700 cases. More than 3,500 cases in East Africa. Nearly 30,000 cases in South Asia and South Asia (Figure 2). The second largest in the world. The third common childhood cancer is non-Hodgkin's lymphoma (estimated 22,000 cases). Renal blastoma (approximately 21,000 cases). Burkitt lymphoma is more common in East and West Africa, with more than 4,000 cases in East Africa and more than 10,000 cases in West Africa.
Figure 3. Modeling predictions for new childhood cancer cases on all continents in 2015-2030 (Source: The Lancet Oncology)
The analysis also shows that in most parts of the world, the number of new cases of childhood cancer is declining or stable each year (Figure 3), but Africa is a notable exception. The region is expected to be between 2015-2030 There will be a large population growth, and this growth will drive an increase in global lymphoma cases. In addition, the study estimates that 92% of new cases of childhood cancer worldwide come from low- and middle-income countries, which is higher than previous Estimate.
Figure 4. 2015-2030 Global New Childhood Cancer Case Modeling Forecast (Source: The Lancet Oncology)
Considering population growth, scientists estimate that the number of new cases of childhood cancer worldwide will reach 6.7 million in 2015-2030. If the health system is not improved, there will be 2.9 million (44%). Cases are "missing" (Figure 4).
In summary, the study shows that at present, the diagnosis of childhood cancer is serious. Foot, especially in South Asia and sub-Saharan Africa (including West Africa, East Africa and South Africa). In addition, the medical model that focuses on the treatment of childhood cancer in a few specialized hospitals is inadequate. Relevant government agencies need to further strengthen the health system, Increased deployment of “accurate diagnosis and effective care for children with cancer” to reduce the number of undiagnosed cancer children.
The above results were published on February 27th in The Lancet Oncology.
Zachary Ward, who led the study, said: "Our model shows that nearly one in two children with cancer have not been diagnosed and may die. 'Untreated'. Accurate estimates of childhood cancer incidence are critical for policy makers to help them identify health care priorities and plan for effective diagnosis and treatment of all cancer children."
Ward also said that as the hidden incidence of childhood cancer begins to emerge, a larger health system is needed to support timely diagnosis. Referral and treatment. In addition, expanding cancer registration is also very Important.
Worth note In addition to the “underestimation of childhood cancer incidence”, a report published in The Lancet Public Health in February also pointed out that 20 years of US data show that cancer incidence is increasing among young adults.
This study analyzed age-specific contemporary morbidity trends in 30 common cancers in the United States, including 12 obesity-related cancers. They obtained 25 state cancer registries in the United States. The data on the incidence of invasive cancer in the 25-84 age group from 1995 to 2014.
The analysis showed that 30 cancers were investigated in 20 years. There were 14672409 cases.
Figure 5 Age-specific annual change in the incidence of 12 obesity-related cancers from 1995 to 2014 (Source: The Lancet Public Health
6 of 12 kinds of obesity-related cancers (multiple myeloma. Colorectal cancer. Uterine cancer. Gallbladder cancer. Kidney cancer and pancreatic cancer) The incidence rate has increased significantly among young adults (25–49 years) and has increased more in the younger generation (Figure 5). For example, In the 45-49 year old population, the average annual growth rate of pancreatic cancer is 0.77%. Among the 30-34 year olds, this ratio is 2.47%. In the 25-29 age group, this proportion is as high as 4.34%. Similarly, kidney cancer. Gallbladder cancer. Uterine cancer. The annual growth rate of colorectal cancer is also the largest in the age group of 25–29 years old, respectively 6.23%.3. 71%.3. 34% and 2.41%.
However, the other 18 cancers did not show a trend of “aging”, only two types of cancer (stomach non-cardia cancer and leukemia) in young adults Incidence increases with age. In addition, the incidence of eight cancers in young adults has decreased, including cancers associated with smoking and HIV infection.
A review article published during the same period stated that although cancer has always been considered as an aging disease, it has been reported earlier that from the middle of the 80s (70s), the knot (straight) bowel cancer The incidence has risen sharply among adults ≤54 years old. This has prompted scientists to explore the trend of cancer rejuvenation and the reasons behind it.
The researchers pushed The prevalence of obesity in the United States has promoted the “youngerization” of some cancers. The prevalence of obesity in the United States more than doubled between 1980 and 2014. However, they did not explain in the paper why not all 12 Obesity-related cancers are showing a trend of “rejuvenation.” Obviously, the reasons behind this need further research, and some other factors play a non-negligible role.
Nevertheless, this is still a report worthy of attention. These findings indicate the need to further closely monitor trends in cancer incidence among young adults and to conduct timely research on the reasons that may lead to this trend.
< p>Related papers:
1]Zachary J Ward, MPH et al. Estimating the total incidence of global childhood cancer: a simulation-based analysis. The Lancet Oncology (2019).
2] .HyunaSung, PhD et al. Emerging cancer trends among young adults in the USA: analysisof a population-based cancer registry. The Lancet Public Health (2019).
1# .How can global Incidence estimatessupport childhood cancer control?
2# .Worldwide recommendations suggest that nearly 1in 2 children with cancer are .left undiagnosed and untreated
3# .Rising cancer incidence in youngeradults: is obesity To blame?
4# . Young people get more and more cancer, this factor can not be ignored! The Lancet is published in 20 years of big data