Understanding Acute Lymphoblastic Leukemia
Recently I transported a child who was diagnosed with acute lymphoblastic leukemia (ALL). I realized within a few minutes of conversing with the physician that I needed to improve my understanding of cancer, and the nomenclature that surrounds it. I will openly admit that it is somewhat depressing to discuss, and is typically not a topic amongst the FOAMed community. However understanding our patients diseases is an integral part of properly care and communication. I may post several blogs on various types of cancer that are either common, or require special considerations for the retrieval clinician. According to the CDC, ALL was the most common type of cancer amongst children between 2001 and 2014 (Siegel, 2017). So what does the clinician need to know about this form of cancer?
Unpacking the word “cancer” into its actual pathology and cellular course is one way to better understand prognosis and treatment options. Within our blood vessels are blood cells that carry out variable functions necessary to life, but where do these cells originate? If one were to shrink down and travel inside a bone, you would run into a spongy compartment known as “bone marrow,” imagine this as the primary factory for blood cell production.
Through a process known as hematopoiesis a stem cell will produce two types of cells, these are known as lymphoids and myeloids. As these cells go through maturation, they will become red blood cells, white blood cells, and platelets. For the purposes of our explanation into ALL we will be focusing on the lymphoid section of this process.
The first phase of a lymphoid maturation creates a precursor cell called a “lymphoblast,” this will be further delineated into T or B lymphocytes. In patients with ALL, these immature white blood cells do not mature and thus rapidly produce with unrestricted growth. That is to say there is a signaling malfunction within the deoxyribonucleic acid (DNA) to limit the expansion. The proliferation of lymphoblastic cells will overflow from the bone marrow and enter into the central circulation. The abundance of immature lymphocytes interferes with normal physiology and makes the host more susceptible to infectious pathogens as well. As a provider it is imperative that we take all infectious disease precautions when caring for the immunosuppressed patient. Specifically If a blood transfusion is needed the following considerations should be taken.
Before diagnosis, the patient may present with flu-like symptoms, fatigue, and sudden weight loss. The diagnostic momentum towards ALL can be multifaceted. A complete blood count (CBC) may come back normal in terms of total white blood cells. However, the diagnosis may lie within something called “the white cell differential” this further specifies each phenotype of white blood cell. An increase in lymphocytes can be a normal finding during viral infections and may not be suspicious as first. Yet, the rate at which these lymphocytes divide can make follow up and repeat blood draws obvious for abnormal proliferation of lymphocytes. This in turn should further peak the physician’s interest in obtaining a blood or bone marrow smear to evaluate for the presence of lymphoblast cells. Cellular characteristics will further then distinguish between B & T cells.
Unrestricted cellular growth amongst lymphoblasts has been contributed to multiple risk factors within genetic mutation and lesser so within environmental factors. One of these genetic mutations is known as trisomy twenty-one, or Down syndrome (American Cancer Society, 2019). The other common genetic mutation that predisposes a child for ALL is translocation of non-homologous chromosomes, specifically 12:21 and 9:22, also known as the “Philadelphia Chromosome” (American Cancer Society, 2019). A translocation occurs when a segment from one chromosome is transferred to a non-homologous chromosome. These abnormal linkage relationships will cause abnormal proteins to form within the cell and can further affect the cell’s function and division.
The initial treatments for all types of cancer has been predicated on killing the cancer cell and in hopes that it will stop dividing. Kill the abundance of lymphoblastic cells, and hope that other cells will regulate as normal. The problem with this modality is that it will kill non-cancer cells as well. This non-specified destruction of the cell cycle can lead to unpleasant side effects in which we see with mainstream cytostatic therapy such as chemotherapy (Kızılocak,2019). Recent attention to targeted therapy research appears to be promising. If a specific portion of the DNA that is prohibiting cellular division inhibition can be halted, a more focused therapy can be provided (Vecchione, 2012). This has been the case with drug discoveries such as imatinib mesylate in treating acute myeloid leukemia (AML) (Sebaa, 2018).
The psychological aspect of a cancer diagnosis such as ALL, is just as important as the medical treatment. It is important that the patient does not give-up fighting (National Cancer Institute, 2018). The predicted emotions include overwhelmed, denial, anger, fear, and hope. In the case of ALL, depending on the age, the child may not be aware of what the diagnosis entails. Rather, the parents will primarily be the recipients of this range of emotion. Each parent will experience a variety and range of these emotions at different times as well. As a healthcare provider, relative, or friend, it is important to allow these emotions to occur in their natural progression (National Cancer Institute, 2018).
As science continues to advance, and cancer remains the forefront of scientific research, we can hope to see break-through therapies begin to populate. It is imperative that humans keep digging deeper into our understanding of cell division, signaling, and genetics. The more we understand about normal, the better we can understand the contrary.
American Cancer Society. (2019, December 2). Risk Factors for Childhood Leukemia. American Cancer Society . American Cancer Society . Retrieved April 29, 2019, from https://www.cancer.org/cancer/leukemia-in-children/causes-risks-prevention/risk-factors.html
(2018, August 20). Feelings and Cancer. National Cancer Institute . Retrieved April 13, 2019, from https://www.cancer.gov/about-cancer/coping/feelings
Kızılocak, H., & Okcu, F. (2019). Late Effects of Therapy in Childhood Acute Lymphoblastic Leukemia Survivors. Turkish Journal of Hematology, 36(1), 1–11. https://doi- org.libraryresources.waldorf.edu/10.4274/tjh.galenos.2018.2018.0150
Sebaa, A., Diaf, M., & Touil, S. C. (2018). Determining the efficiency of the Imatinib mesylate and monitoring of relapse and emergence of IM resistance in Algerian adult patients with Chronic Myeloid Leukaemi. South Asian Journal of Experimental Biology, 8(3), 103–108. Retrieved from http://search.ebscohost.com.libraryresources.waldorf.edu/login.aspx?direct=true&db=a9h&AN=135502882&site=eds-live
Siegel, D. (2017, September 15). Rates and Trends of Pediatric Acute Lymphoblastic Leukemia — United States, 2001–2014. Centers for Disease Control and Prevention. Retrieved April 29, 2019, from https://www.cdc.gov/mmwr/volumes/66/wr/mm6636a3.htm
Soulier, J., & Cortes, J. (2015). Introduction to the review series on acute lymphoblastic leukemia. Blood, 125(26), 3965-3966. Accessed April 12, 2019.https://doi.org/10.1182/blood-2015-05-635300.