Understanding Leukemia: Causes, Types, and Risk Factors
This article explores the causes, types, and risk factors of leukemia, highlighting key statistics and treatment options. It explains how leukemia originates from blood stem cells, describing its main variants—ALL, CLL, AML, and CML—and their impact on different age groups. Understanding these differences helps in early diagnosis and effective management, improving patient outcomes.
The American Cancer Society (ACS) projects approximately 60,300 new leukemia cases are diagnosed in the United States this year, with about 24,370 fatalities. Leukemia begins in blood stem cells as either immature myeloid cells, which develop into platelets, monocytes, or granulocytes involved in clotting and fighting infections, or immature lymphoid cells, including lymphocytes B, T, or NK cells that combat infections. These abnormal blast cells multiply rapidly, displacing healthy cells.
The disease manifests in four main types, classified based on whether they originate from lymphoid or myeloid stem cells: lymphoblastic or myelogenous leukemia.
1. Acute lymphocytic leukemia
The ACS estimates around 5,960 new cases of acute lymphocytic leukemia (ALL) annually in the U.S., resulting in approximately 1,470 deaths. Mostly affecting children under five, especially boys, ALL is rare in adults under 40. Younger patients tend to respond better to intensive treatments, which include chemotherapy, radiation, stem cell transplantation, and immunotherapy.
2. Chronic lymphocytic leukemia
Chronic lymphocytic leukemia (CLL) primarily affects older adults, with the average diagnosis age around 70. CLL progresses slowly but can spread to organs like the liver or spleen if untreated, often requiring radiation, chemotherapy, stem cell transplants, or immunotherapy. It is rare in patients under 40, accounting for roughly 20,940 new cases and 4,510 deaths yearly.
3. Acute myeloid leukemia
Considered the most common leukemia, acute myeloid leukemia (AML) causes approximately 19,520 new cases and 10,670 deaths annually. It predominantly affects older adults, with a median diagnosis age of 68. AML progresses quickly but can be managed effectively through targeted treatment, chemotherapy, radiation, and stem cell transplants, offering younger patients a remission rate of 70-80% and a five-year survival around 26%.
4. Chronic myeloid leukemia
Annually, about 8,430 Americans are diagnosed with chronic myeloid leukemia (CML), resulting in approximately 1,090 deaths. Mainly affecting older adults aged 65 and above, CML develops due to genetic mutation involving the Philadelphia chromosome, leading to abnormal white blood cell growth. Standard treatments include targeted oral chemotherapy, radiation, stem cell therapy, and immunotherapy.
