Understanding Leukemia: Causes and Variants

This article provides a comprehensive overview of leukemia, including its causes, main types, age groups affected, and treatment options. It highlights the prevalence of each type and emphasizes the importance of early diagnosis and proper medical care. Essential for understanding this blood cancer, the article aims to inform readers about the disease's development, symptoms, and recent advancements in treatment strategies to improve patient outcomes.

Understanding Leukemia: Causes and Variants

An estimated 60,300 new cases of leukemia are expected in the United States this year, according to the American Cancer Society (ACS). Tragically, about 24,370 lives are projected to be lost due to the disease.

Leukemia develops from blood stem cells, either immature myeloid cells (which form monocytes, platelets, granulocytes responsible for clotting and fighting infections) or lymphoid cells (such as B, T, or NK lymphocytes that combat infections). These immature cells, called blast cells, multiply uncontrollably, displacing healthy blood cells.

Leukemia is classified into four primary types based on whether they originate from lymphoid or myeloid stem cells. The main categories are lymphoblastic and myelogenous leukemias:

1. Acute lymphocytic leukemia (ALL)
About 5,960 new ALL cases are diagnosed annually in the U.S., resulting in approximately 1,470 deaths. Predominantly affecting children (three out of four leukemia cases in kids under 5), ALL is rare in individuals over 40. Younger patients generally respond better to intensive treatments, including chemotherapy, radiation, stem cell transplants, and immunotherapy.

2. Chronic lymphocytic leukemia (CLL)
CLL mainly affects older adults, with an average diagnosis age of around 70. Although slower progressing, untreated CLL can spread rapidly to organs like the liver or spleen, often requiring radiation, chemotherapy, stem cell therapy, or immunotherapy.

ALL is uncommon in children under 40, with about 20,940 new cases yearly and around 4,510 deaths. CLL, on the other hand, tends to grow slowly but can metastasize if untreated.

3. Acute myeloid leukemia (AML)
AML is the most prevalent leukemia, with approximately 19,520 new cases and 10,670 deaths each year in the U.S. It primarily affects older adults, with a median diagnosis age of 68. AML grows rapidly, but younger patients treated with targeted therapies, radiation, chemotherapy, or stem cell transplants often achieve remission rates between 70-80%, with a 5-year survival rate around 26%.

4. Chronic myeloid leukemia (CML)
Annually, about 8,430 individuals are diagnosed with CML, with approximately 1,090 fatalities. Mainly affecting seniors (average diagnosis age 65+), CML results from genetic changes, specifically an abnormal Philadelphia chromosome that leads to uncontrolled white blood cell proliferation. Treatments include radiation, oral chemotherapy, stem cell therapy, and immunotherapy.