What is leukemia

Overview

Leukemia is a malignant cancer of blood-forming tissues, primarily affecting bone marrow and lymph nodes. It occurs when immature blood cells (blasts) multiply uncontrollably, crowding out healthy blood cells. This results in anemia, infections, and bleeding problems. Leukemia affects both children and adults, though it is the most common cancer in children, accounting for about 28% of pediatric cancers.

Types of Leukemia

Leukemia is classified by cell type and progression speed:

• Acute Lymphoblastic Leukemia (ALL): Most common childhood leukemia; fast-growing, affects lymphoid cells
• Acute Myeloid Leukemia (AML): Affects myeloid cells; more common in adults; most common acute leukemia in adults
• Chronic Lymphocytic Leukemia (CLL): Slow-growing; primarily affects adults over 70; often discovered incidentally
• Chronic Myeloid Leukemia (CML): Slow-growing; often associated with Philadelphia chromosome; very responsive to targeted therapy

Causes and Risk Factors

Most leukemias develop from genetic mutations occurring spontaneously without clear cause. Known risk factors include:

• Genetic predisposition and family history
• Exposure to ionizing radiation (nuclear accidents, excessive X-rays)
• Exposure to certain chemicals (benzene) and pesticides
• Prior chemotherapy or radiation for other cancers
• Certain genetic conditions (Down syndrome, Fanconi anemia)
• Smoking (increases CML risk in adults)

Symptoms and Diagnosis

Common symptoms: Persistent fatigue, unexplained fever, frequent infections, easy bruising or bleeding, enlarged lymph nodes, bone or joint pain, pale skin, and night sweats. Diagnosis: Complete blood count (CBC) showing abnormal white blood cells, bone marrow biopsy confirming leukemia type, chromosomal analysis for targeted treatment planning, and genetic testing for specific mutations.

Treatment Options

Treatment depends on leukemia type, patient age, and health status. Standard approaches include:

• Chemotherapy: Induction therapy followed by consolidation therapy to kill cancer cells
• Targeted therapy: Tyrosine kinase inhibitors (especially effective for CML)
• Immunotherapy: CAR-T cell therapy showing remarkable results in ALL
• Stem cell transplantation: Replacing diseased bone marrow with healthy donor cells
• Radiation therapy: Targeting specific areas or whole-body preparation for transplant

Prognosis and Survival

Prognosis varies significantly by type. Childhood ALL has a five-year survival rate exceeding 90%, while adult ALL is approximately 65%. CML patients on targeted therapy have near-normal life expectancy. AML survival rates in adults range from 30-50%, improving with newer treatments. CLL generally progresses slowly; many patients live 10+ years with treatment.