An Overview of Acute Lymphocytic Leukemia: A Fast-Progressing Cancer of the Bone Marrow Cells
Annie Hu, Collierville High School, Collierville, Tennessee, USA
Acute Lymphocytic Leukemia (ALL) is a type of cancer that occurs in the white blood cells. It can quickly travel through the bloodstream and cause symptoms such as joint pain and frequent infections (Stuart, 2020). It affects the lymphocytes, a type of white blood cell that eventually builds up in the liver and lymph nodes (St. Jude, n.d.). What’s even more concerning is that leukemia has been on the rise in many countries. Since 1975, it has risen by almost 35% (Goodman & Miller, 2016). Worldwide, the number of cases has increased from 49,100 in 1990 to 64,200 in 2017 (Dong, 2020).
There are many types of leukemia categorized by where they develop and how fast they progress. ALL is particularly dangerous due to its ability to spread quickly. If cancer treatment is not initiated within the first few months of onset, it can quickly become life-threatening (American Cancer Society, 2018). ALL arises when bone marrow cells develop mutations in their DNA. This causes them to grow and divide uncontrollably, producing immature cells that develop into lymphoblasts (Mayo Clinic, n.d.). These immature cells eventually crowd out the healthy ones that help the body fight against infections and diseases. Without enough normal white blood cells, anemia and bleeding can become more common and cause extreme discomfort (National Institutes of Health, n.d.).
Despite the presence of ALL worldwide, the distribution of cases is not homogenous. In a study conducted in 2012, scientists noticed that most of the cases originated in developed and rapidly developing countries. In contrast, less developed countries such as Namibia, South Africa, and Botswana had the lowest age standardized incidence rates (Yi et al., 2020). Age-standardized mortality rates (ASMR) also followed this trend. This should raise concerns regarding the negative effect of increased development and globalization on human health.
Although incidence and mortality rates are higher in developed countries, the trend of these rates seems to differ. In developed countries, ASMR rapidly decreased from 0.72 in 1990 to 0.46 in 2017. In contrast, the mortality rates in developing countries, such as those in Latin American’s Andean Region, had the fastest increase. This further demonstrates the correlation between rapid development and cancer rates. Although ALL may pose a more prominent problem to the developed world currently, it could become an increased burden to less developed countries in the future. A sign of this is the increased age-standardized incidence rates (ASIR) in developing countries, namely El Salvador, Guatemala, and Ecuador. This could heavily impact the country’s population, especially if there are large socioeconomic gaps within the country preventing certain ALL patients from getting adequate health care.
Figure 1. This map shows the relative trend of incidence rates in ALL from 1990–2017 (Yi et al., 2020).
Although there is no definite cause for ALL, many factors can influence a person’s risk of developing the disease. For instance, exposure to ionizing radiation can severely damage a cell’s DNA. In a study conducted on survivors of the atomic bomb explosions in Hiroshima and Nagasaki, leukemia rates in people within 1,000m were 20 times higher than rates outside the region (Mahoney, 1955). However, as seen by ASIR rates, the occurrence of ALL in developed regions has gradually decreased, partly due to the reduction of radiation over time. Another risk factor for ALL is benzene, a chemical used in paints, plastics, and cigarette smoke. Benzene has been shown to cause tumors and chromosomal changes in bone marrow cells (American Cancer Society, n.d.). Considering that there are about 1.1 billion smokers worldwide, this is a prominent issue that needs to be addressed.
Survival rates for ALL have significantly increased over the past few decades. For people under the age of 20, the five-year survival rate is now about 90%. In children, up to 98% go into remission after treatment, and 90% get completely cured (American Cancer Society, 2020). However, in some developing countries such as India, economic challenges have significantly affected cancer care. For example, a shortage of resources and expensive medical care have caused frequent challenges and abandonment of chemotherapy (Global Oncology, n.d.). This poses a big problem, as India currently has one of the highest incidence rates. For other developing countries, economic challenges could also cause the inability to treat ALL, possibly lowering the quality of life for patients and causing death that could have been prevented. In a study conducted in 2017, age-standardized survival rates ranged from 52.4% in countries such as Colombia to 91.6% in the German registries (PMC, 2017). This shows that global inequalities in health care have caused differences in survival from leukemia. Although these gaps are narrowing, they remain noticeable.
With the global prevalence of ALL, continuing the study and research of this illness is the key to increasing survival rates and hopefully finding a long-awaited cure.
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