Leukemia in children and the elderly
Leukemia is a type of blood cancer that develops from the rapid, uncontrolled production of dysfunctional, immature white blood cells in the bone marrow. Do you know it is more common in men than in women?
This cellular overcrowding leads to the primary complications of the disease: anemia, frequent infections, and easy bruising or bleeding. For patients and caregivers, understanding that leukemia is not a single disease, but a spectrum of disorders ranging from aggressive acute forms to slow-growing chronic types, is the first step toward effective management.
In this article, you can find diagnosis patterns, staging, and cutting-edge therapies. I have considered parental concerns regarding pediatric ALL (Acute Lymphoblastic Leukemia) to geriatric management of CLL (Chronic Lymphocytic Leukemia) to bridge the gap between complex clinical data and actionable patient knowledge.
Comparison of normal blood with leukemia
Key Aspects of Leukemia
Leukemia is fundamentally a disorder of the hematological system. To understand its impact, one must look at the specific ways it disrupts the body’s equilibrium:
Bone Marrow Crowding
The primary site of pathology is the bone marrow. As leukemic cells multiply, they physically take up the space required for healthy blood production.
Immature Blasts
The white blood cells produced are immature, meaning they lack the biological machinery to fight infection, despite being present in high numbers.
Systemic Spread
Because blood circulates throughout the entire body, leukemia is considered a systemic (whole-body) disease from the moment of diagnosis.
Secondary Cytopenia
The crowding out effect results in a shortage of vital components:
- Anemia: Shortage of red blood cells leading to profound exhaustion.
- Thrombocytopenia: Low platelets cause clotting issues and easy bruising.
- Neutropenia: Lack of functional neutrophils, making the body vulnerable to minor pathogens.
Types of Leukemia
Leukemia is classified based on two factors: the speed of progression and the type of white blood cell involved (Lymphoid vs. Myeloid).
Acute Leukemia
Acute forms require immediate, aggressive treatment due to the rapid accumulation of non-functional cells.
Chronic Leukemia
These forms develop over the years. Patients may remain asymptomatic for long periods before requiring intervention.
- CLL (Chronic Lymphocytic Leukemia): The most common adult leukemia, often discovered during routine blood tests in seniors. In 2026, NCCN guidelines (emphasise time-limited targeted therapies.
- CML (Chronic Myelogenous Leukemia): Distinguished by the Philadelphia Chromosome t(9;22), which triggers an overproduction of granulocytes.
Age-dependent Leukemia
The biological behaviour of leukemia varies significantly across the human lifespan, requiring age-tailored clinical approaches.
Children under 15
In the pediatric population, leukemia accounts for nearly 30% of all childhood cancers.
- ALL Dominance: Approximately 3 out of 4 pediatric cases are ALL.
- High Cure Rates: Pediatric ALL now sees a 5-year relative survival rate of approximately 94% in the US.
- Genetic Research: The focus in 2026 is on reducing long-term toxicity from treatments to ensure a high quality of life for survivors.
Adults over 55
Leukemia in older adults is often a different biological entity, characterised by accumulated genetic mutations.
- CLL and AML Prevalence: These are the most frequent diagnoses in this age bracket.
- Comorbidity Management: Treatment must be balanced against organ functions, which may be compromised by age.
- Treatment Innovation: Newer chemo-free combinations are being used to treat frail patients who cannot tolerate intensive protocols.
Symptoms of Leukemia
Because leukemic cells infiltrate various systems, the symptoms are often diverse and can be mistaken for the flu or overexertion.
Systemic Fatigue
Leukemia-induced fatigue is a profound, drenching exhaustion that persists despite adequate rest. It is primarily driven by anaemia, where a deficit of healthy red blood cells reduces oxygen delivery to tissues. This symptom often includes breathlessness and dizziness, significantly impacting daily functioning.
Frequent Infections
Leukemia causes the bone marrow to produce immature white blood cells (blasts) that cannot effectively fight pathogens. This neutropenia leaves the body vulnerable to recurring fevers, mouth sores, and infections that are unusually severe or slow to heal.
Easy Bleeding/Bruising
Low platelet counts (thrombocytopenia) prevent blood from clotting normally. Patients may notice frequent nosebleeds, bleeding gums, or small red/purple skin spots called petechiae. Bruises often appear without trauma and take much longer than usual to disappear.
Lymph Node Swelling
Abnormal lymphocytes can accumulate in the lymph glands, causing painless lumps usually in the neck, armpits, or groin. In chronic forms like CLL, these swollen nodes are often one of the earliest visible indicators of the disease.
Bone and Joint Pain
This pain occurs as the bone marrow becomes overcrowded with malignant cells, creating internal pressure that signals deep, throbbing aches or sharp stabs during movement. It is most commonly felt in the long bones of the arms and legs.
Night Sweats
Leukemia-related night sweats are often drenching, requiring a change of clothes or sheets. They occur as the immune system releases hormones and inflammatory signals in an attempt to fight the rapidly dividing cancer cells.
Enlarged Organs
Malignant cells can infiltrate and build up in the spleen (splenomegaly) or liver (hepatomegaly), and thus the size of the organ increases. This often leads to a persistent feeling of fullness, abdominal bloating, or discomfort under the ribs on the left side of the body.
Diagnosis of Leukemia
A definitive diagnosis requires a series of specialised tests to identify the specific genetic fingerprint of the cancer.
Physical Exam
A clinician begins by checking for physical indicators of blood cell dysfunction. Key signs include enlarged lymph nodes, a swollen liver or spleen (splenomegaly), and signs of infection. They also look for cutaneous markers like petechiae (tiny red spots) or unusual bruising, which suggest low platelet counts.
Complete Blood Count (CBC)
The CBC is typically the first step. It quantifies white blood cells, red blood cells, and platelets. In leukemia, the count may show abnormally high white cells (often immature blasts) and low levels of red cells and platelets. A peripheral blood smear is also performed to examine cell morphology under a microscope.
Bone Marrow Biopsy
This procedure involves extracting a small sample of liquid marrow (aspiration) and a core piece of bone tissue (biopsy), usually from the hip. It is the gold standard for confirming a diagnosis, as it allows pathologists to determine the percentage of leukemic blasts and the overall cellularity of the marrow.
Flow Cytometry
This technology uses lasers to analyse the physical and chemical characteristics of cells. By tagging cells with fluorescent antibodies, doctors can identify specific surface markers (antigens). This immunophenotyping is crucial for distinguishing between lymphoid and myeloid lineages and identifying specific leukemia subtypes.
Cytogenetic Analysis
This lab test examines the chromosomes of leukemic cells for abnormalities such as translocations, deletions, or extra chromosomes. Identifying specific mutations, such as the Philadelphia Chromosome t(9;22), is vital for determining the prognosis and selecting targeted therapies that attack the specific genetic drivers of the cancer.
Minimal Residual Disease (MRD) Testing
MRD testing uses highly sensitive molecular techniques (like PCR or NGS) to find one leukemic cell among a million healthy ones (See article by Tiexiera et al. 2023 for details). It is used after treatment to see if any microscopic "traces" of cancer remain, helping doctors predict relapse risk and decide whether further therapy or a transplant is necessary.
Treatment of leukemia
Leukemia treatment is highly personalised, balancing the aggressiveness of the malignancy with the patient’s physical resilience. Decisions are guided by genomic profiling, identifying specific mutations that may respond to "smart" drugs rather than traditional toxins alone.
Multiphase Chemotherapy
Chemotherapy remains a cornerstone, typically structured into three critical phases to ensure deep remission:
- Induction: A short, intensive phase (approx. 4 weeks) aimed at killing the majority of leukemia cells to achieve morphologic remission.
- Consolidation (Intensification): Lasting several months, this phase targets residual, undetectable cells to prevent early relapse.
- Maintenance: A long-term, lower-dose regimen (often up to 2 years) to ensure the cancer does not return.
Precision Targeted Therapy
Targeted agents act like guided missiles, attacking proteins that drive cancer growth. BTK inhibitors like ibrutinib and zanubrutinib have revolutionised Chronic Lymphocytic Leukemia (CLL) care by blocking B-cell receptor signalling, often replacing intensive chemo for elderly patients.
Precision Targeted Therapy
Targeted agents act like guided missiles, attacking proteins that drive cancer growth. BTK inhibitors like ibrutinib and zanubrutinib have revolutionised Chronic Lymphocytic Leukemia (CLL) care by blocking B-cell receptor signalling, often replacing intensive chemo for elderly patients.
Strategic Radiation & TBI
Radiation is rarely a standalone cure for leukemia but serves vital supportive roles. It is used to shrink symptomatic organ enlargement (spleen/liver) or as Total Body Irradiation (TBI), a specialised protocol to "clear" the bone marrow and suppress the immune system immediately before a stem cell transplant.
Advanced Immunotherapy
Immunotherapy harnesses the patient’s immune system. Blinatumomab is a bispecific T-cell engager (BiTE) that physically bridges healthy T-cells to CD19-positive leukemia cells. By forcing this direct contact, the immune system can identify and destroy cancer cells that chemotherapy might miss.
Stem Cell Transplant
A Stem Cell Transplant is a high-intensity procedure that replaces a patient’s diseased bone marrow with healthy hematopoietic stem cells. The process begins with conditioning, high-dose chemotherapy or radiation, to eliminate leukemic cells and clear the marrow space. In an allogeneic transplant, stem cells from a matched donor generate a new immune system that can actively hunt residual cancer cells, known as the Graft-versus-Leukemia (GvL) effect. This curative approach is essential for high-risk or relapsed leukemia where standard treatments fail to provide long-term remission.
Advancement in Leukemia Treatment
The Chimeric Antigen Receptor (CAR) T-cell therapy has revolutionised the treatment landscape for B-cell acute lymphoblastic leukemia (ALL). This process involves genetically re-engineering a patient’s own immune system to identify and destroy malignant cells with surgical precision.
The 5-Step Genetic Re-engineering Process:
Collection (Leukapheresis): T-cells are harvested from the patient's blood using an apheresis machine. This "raw material" is then transported to specialised manufacturing facilities.
Genetic Modification: Scientists use viral vectors or base-editing technology to insert a lab-made gene into the T-cells. This gene instructs the cells to grow Chimeric Antigen Receptors (CARs) on their surface, specifically targeting proteins like CD19.
Expansion: These newly "armed" T-cells are grown in massive quantities in a laboratory environment until they reach the hundreds of millions.
Conditioning: Prior to re-infusion, patients often undergo low-dose chemotherapy to reduce existing white blood cell levels, creating "space" for the CAR-T cells to thrive.
Infusion: The final "living drug" is infused back into the patient. Once inside, these cells act as a permanent surveillance force, multiplying and attacking leukemic blasts throughout the body.
CAR-T cells (blue) attacking cancer cells carrying a genetically modified receptor (orange). Adapted from Science.org
Comparative Status of Leukemia Among Cancers
Leukemia differs from solid tumours in its systemic nature and diagnostic markers (see Table below). You can learn about the most prevalent carcinomas and rare sarcomas.
Regional Distribution of Leukemia
Global incidence and mortality are influenced by regional healthcare infrastructure and environmental triggers.
Future Strategies for Leukemia
The future of leukemia care lies in non-toxic, molecularly guided interventions. By moving away from indiscriminate cellular poisons, researchers are creating a more "surgical" approach within the bloodstream.
Precision Medicine & MRD-Driven Care
Minimal Residual Disease (MRD) tracking has evolved into a real-time GPS for oncology. By using ultra-sensitive sequencing to detect one leukemic cell in a million, therapy is adjusted instantly. If MRD levels rise, clinicians can trigger preemptive salvage with targeted agents long before a physical relapse occurs, effectively avoiding the toxicity of unnecessary over-treatment.
Menin Inhibitors
It is a breakthrough for aggressive AML types harbouring KMT2A rearrangements or NPM1 mutations. These inhibitors, such as revumenib, work by blocking the interaction between the menin protein and leukemia-promoting complexes. In 2026, new combination trials (Menin + Venetoclax) are showing response rates exceeding 80% in high-risk patients who previously had few options.
AI in Prognosis
Artificial Intelligence has transitioned from research to the clinic. New AI-driven algorithms now integrate genomic, transcriptomic, and imaging data to predict patient responses to immunotherapies with over 80% accuracy. These Digital Twins allow doctors to simulate treatment success before a single dose is administered, ensuring patients receive the most effective regimen the first time.
Conclusion
In 2026, leukemia is no longer defined merely as a blood cancer but as a collection of genetic challenges that we are learning to solve. From the rapid production of dysfunctional white cells to the successful implementation of T-cell engineering, the progress is undeniable. Survival rates have reached a milestone 70% across all types, and the shift toward chemo-free regimens is sparing patients from long-term side effects. While regional disparities persist, the global oncology community is moving toward a future where leukemia is either a curable childhood condition or a manageable chronic adult disease.
FAQs
What is the Philadelphia Chromosome?
It is a specific genetic mutation found in CML patients, t(9;22), that targeted drugs like Imatinib can block.
Can leukemia be detected in a routine physical?
Yes, through a Complete Blood Count (CBC), which shows abnormal cell levels even before symptoms appear.
Is CAR-T therapy only for children?
No, in 2026, it was approved for various adult B-cell leukemias and lymphomas as well.
Why does leukemia cause night sweats?
The body's immune system releases chemicals to fight the cancer cells, which can trigger a fever response and sweating.
Is leukemia more common in men?
Yes, statistics consistently show that males exhibit higher incidence and mortality rates globally.
What are the main causes of leukemia?
While often unknown, risk factors include benzene exposure, high-dose radiation, and certain genetic syndromes.
What is the difference between remission and a cure?
Remission means no signs of cancer are present; a "cure" is generally considered after years of remission without recurrence.