Adults develop leukemia, a cancer that originates in the blood-forming cells of the bone marrow. This condition involves the uncontrolled production of abnormal white blood cells, which prevents the bone marrow from creating healthy blood components like red blood cells and platelets. Leukemia is a serious diagnosis, but advancements in medical science have led to effective and targeted treatments. While the disease is often associated with childhood, the overall incidence of leukemia is highest in adults, particularly those over the age of 60. Each form of the disease has its own progression and treatment strategy.
The Types of Leukemia Most Common in Adults
Leukemia is categorized based on the speed of progression, either acute (rapidly advancing) or chronic (slowly developing), and the type of white blood cell affected, either myeloid or lymphoid. The four main types of the disease affect adults, though the prevalence varies significantly compared to children. Chronic Lymphocytic Leukemia (CLL) is the most frequently diagnosed form of leukemia in adults, accounting for about one-quarter of all cases. This slow-growing cancer originates in the lymphoid cells and often allows patients to live for many years without immediate treatment.
Acute Myeloid Leukemia (AML) is the most common acute form in adults, involving the rapid proliferation of immature myeloid cells in the bone marrow. AML is considered aggressive because of its fast progression, and it primarily affects older adults, with the median age at diagnosis being around 68. Chronic Myeloid Leukemia (CML) is a chronic, slow-growing cancer of the myeloid cell line, characterized by the Philadelphia chromosome. This specific genetic abnormality, a fusion of chromosomes 9 and 22, creates a new gene that drives the uncontrolled growth of white blood cells.
Acute Lymphoblastic Leukemia (ALL) is the least common of the four main types in adults, though it is the most prevalent form in children. Like its acute myeloid counterpart, ALL is a fast-progressing disease that originates in the lymphoid cells, requiring immediate, intensive treatment. While ALL in adults can be cured, the prognosis is often less favorable than it is for children with the same diagnosis. The specific cell lineage and progression speed determine the urgency and type of treatment.
Recognizing the Signs and Symptoms
The physical manifestations of leukemia in adults are often vague and can be mistaken for less serious illnesses, sometimes delaying diagnosis. Persistent fatigue and weakness are common symptoms, often resulting from a lack of healthy red blood cells, known as anemia. This reduction in oxygen-carrying capacity can also lead to pale skin and shortness of breath, particularly during physical exertion.
Leukemia cells crowd out the healthy white blood cells, leading to a weakened immune system and a tendency toward frequent or severe infections. Unexplained symptoms like fevers, night sweats, and unintentional weight loss are common signs, collectively known as B symptoms. The reduction in platelets, which are necessary for blood clotting, can cause easy bruising, bleeding gums, nosebleeds, or the appearance of tiny red spots under the skin called petechiae. Swollen lymph nodes in the neck, armpits, or groin, or a feeling of fullness under the ribs due to an enlarged liver or spleen, are also possible.
Key Risk Factors and Prevention
A person’s risk of developing leukemia increases significantly with age, with most adult cases diagnosed in people over 60. Exposure to certain environmental factors and chemicals is also a well-established risk factor, particularly for Acute Myeloid Leukemia (AML). High-dose exposure to ionizing radiation, such as from nuclear accidents or prior medical radiation treatments, can damage the DNA in blood-forming cells.
Chemical exposure, specifically to the solvent benzene, found in some industrial settings and cigarette smoke, significantly increases the likelihood of developing AML. Smoking itself is a major factor, as it introduces dozens of carcinogens into the body, and researchers estimate that approximately 20% of AML cases may be linked to tobacco use. Furthermore, individuals who received chemotherapy or radiation therapy for a previous cancer diagnosis may have a higher risk of developing a secondary, treatment-related leukemia. While most risk factors cannot be completely eliminated, avoiding smoking and minimizing exposure to known industrial chemicals like benzene are the most direct preventative actions.
Diagnosis and Management
The diagnostic process for leukemia typically begins after a patient reports persistent, non-specific symptoms or if routine blood work returns abnormal results. A Complete Blood Count (CBC) is the initial blood test that provides information on the number of red blood cells, white blood cells, and platelets, often revealing an abnormal count of white blood cells or a lack of healthy blood components. If the blood test suggests leukemia, a bone marrow biopsy is performed, usually by taking a sample from the hipbone using a thin needle.
The bone marrow sample is then examined to confirm the presence of leukemia cells and to identify the specific type and subtype. Genetic testing, including flow cytometry and cytogenetics, is performed to look for specific chromosomal abnormalities or gene mutations, like the Philadelphia chromosome in CML. Treatment is tailored to the specific leukemia type, the patient’s age, and their overall health, and it generally involves a combination of modalities:
- Chemotherapy to kill the cancer cells.
- Targeted therapy drugs that specifically attack the abnormalities in the cancer cells.
- Immunotherapy that uses the body’s own immune system.
- In some cases, a stem cell transplant to replace the diseased bone marrow.