Leukemia

By Sanjana Malkareddy

By the NCI from Unsplash

What is Leukemia?

Leukemia is a cancer affecting the blood-forming cells. Generally, leukemia is a cancer of the white blood cells, but it may affect other types of blood cells, leading to the rapid, uncontrolled growth of these abnormal cells. This growth resides within the bone marrow, where the majority of your body’s blood is produced. There are various types of leukemia, which are divided based on whether they’re acute, fast-growing, or chronic, slow-growing leukemias and whether they originate from myeloid cells or lymphoid cells.

Symptoms:

Leukemia symptoms vary, depending on the type of leukemia. 

Common signs and symptoms of Leukemia are:

• Fatigue, tiring easily

• Night sweats or chills

• Frequent or severe infections

• Shortness of breath

• Pale skin

• Losing weight without trying

• Swollen lymph nodes in your neck, underarm, groin, or stomach, enlarged liver or spleen

• Easy bleeding or bruising

• Recurring nosebleeds

• Tiny red spots in your skin(petechiae)

• Bone pain or tenderness

Causes:

Scientists don’t understand the exact causes of Leukemia. It seems to develop from a combination of genetic and environmental factors. While anyone can develop Leukemia, scientific studies have shown that certain factors may increase your risk for Leukemia, including

• Previous cancer treatment

  • Any past cancer treatments involving radiation or chemotherapy may increase the likelihood of developing some types of leukemia.

• Smoking

  • Any exposure to smoking or second-hand smoke may increase the likelihood of acute myelogenous leukemia

• Exposure to industrial chemicals

  • Benzene and formaldehyde chemicals are known to cause cancer and these chemicals are often found in building materials and household chemicals.

• Certain genetic disorders

  • Genetic disorders, such as neurofibromatosis, Klinefelter syndrome, Schwachman-Diamond syndrome, and Down syndrome, are known to increase the  risk of cancer

• Family history of Leukemia

  • Research suggests that some types of leukemia may run in families.  In most cases, however, having a relative with leukemia doesn’t mean that you or another family member will also develop leukemia. Doctors can do genetic testing based on a person's family history to assess the risk of cancer.

How Leukemia forms:

Leukemia happens when some blood cells have changes, called mutations, in their DNA. DNA is like a set of instructions that tells the cells in our body how to work. Normally DNA makes sure that cells grow and divide at the right pace and then die when they’re supposed to. But in Leukemia, the mutations tell the cells to keep growing and dividing nonstop.

As a result, the production of blood cells spins out of control. Over time, these abnormal cells take over the bone marrow, leaving less space for healthy blood cells. This leads to fewer normal white blood cells, red blood cells, and platelets, which causes the symptoms of Leukemia.

Leukemia classification and types:

Leukemia is categorized based on how fast it progresses and the type of cells it affects.

Speed of Progression

1. Acute Leukemia : In acute leukemia, the abnormal cells are immature and can't do their normal functions. These cells grow and multiply uncontrollably, which means the disease worsens fast. Acute leukemia needs immediate and aggressive treatment.

2. Chronic Leukemia : Chronic Leukemia develops more slowly and involves more mature blood cells. These cells can sometimes function normally for a while before symptoms appear. Some types of chronic leukemia don't show symptoms early on and may go unnoticed for a few years.

Type of White Blood Cells Affected

1. Lymphocytic Leukemia : This type affects lymphocytes, which are part of the immune system. Lymphocytes are found in lymphatic tissue, which helps the body fight infections. 

2. Myelogenous Leukemia : This type impacts myeloid cells, which are responsible for producing red blood cells, white blood cells, and platelets.

Types of Leukemia

1. Acute Lymphocytic Leukemia (ALL):  

This is the most common type of leukemia in children, but it can also affect adults.

2. Acute Myelogenous Leukemia (AML):  

AML is common in both children and adults. It’s the most frequent type of acute leukemia in adults

3. Chronic Lymphocytic Leukemia (CLL):  

CLL is the most common chronic leukemia in adults. People with CLL may feel fine for years before needing treatment.

4. Chronic Myelogenous Leukemia (CML):  

CML mostly affects adults. It can remain symptom-free for a long time before the leukemia cells start growing faster.

5. Other Types:

There are also rare forms of leukemia, such as hairy cell leukemia, myelodysplastic syndromes, and myeloproliferative disorders.

By understanding these classifications, doctors can decide on the best treatment approach for each patient.

Diagnosis and Tests:

The process of diagnosing leukemia involves several tests and procedures to confirm the disease and determine its type and subtype.

Blood Tests

1. Complete Blood Count (CBC): This test checks for abnormalities in blood cell counts. For example, low red blood cells (anemia), low platelets, or high white blood cells could indicate leukemia.

2. Peripheral Blood smear (PBS): A pathologist examines blood cells under a microscope to investigate abnormalities found in the CBC.

3. Flow Cytometry & Immunophenotyping: These advanced tests identify specific markers on cells to differentiate healthy cells from cancerous ones and classify the type of leukemia.

Bone Marrow Tests

1. Bone Marrow Biopsy: In this test a long needle is used to extract a sample of bone marrow (usually from the hip bone) to check for cancerous cells.

Spinal Tap (lumbar puncture):

This test examines the cerebrospinal fluid (CSF) to see if leukemia has spread to the brain or spinal cord.

Genetic and Molecular testing:

These tests analyze DNA, RNA, or proteins in blood or bone marrow to detect mutations, guide treatment, and identify targeted therapies which include:

• Next Generation Sequencing (NGS)

• Fluorescence in situ Hybridization (FISH)

Imaging Tests

While not used to diagnose leukemia directly, scans like CT, MRI, or PET may detect complications like enlarged lymph nodes or organ involvement.

By combining these tests, doctors can confirm leukemia, identify its type, and plan the best treatment for the patients.

Treatment:

The treatment for leukemia depends on the patient's age, health, the type of leukemia, and how far it has spread. Below are the common treatment options for leukemia:

1. Chemotherapy

   • The main treatment using drugs to kill leukemia cells

   • Can be administered as pills or through injections

2. Targeted Therapy

   • Focuses on specific cancer cell abnormalities to stop their growth

3. Radiation Therapy

   • Uses high energy beams to kill or shrink leukemia cells

   • Sometimes used before a bone marrow transplant

4. Bone marrow transplant

   • Replaces diseased bone marrow with healthy stem cells from you or a donor

5. Immunotherapy

   • Boosts your immune system to fight leukemia by blocking cancers hiding mechanisms

6. CART-T cell therapy

   • Reprograms your immune cells to attack leukemia cells

7. Clinical trials

   • Offers experimental treatments, but risks and benefits very.

Can Leukemia be completely cured?

The possibility of curing leukemia depends on several factors, including the type of leukemia, the patient’s age, overall health, and how early it is detected. Below is a brief overview:

Acute Leukemia

• Acute Lymphoblastic Leukemia (ALL):

ALL has a high cure rate, especially in children. Many achieve long-term remission or are considered cured after treatment. In adults, the cure rate is lower but still possible with intensive treatment.

• Acute Myeloid Leukemia (AML):

AML can be cured, particularly in younger patients who respond well to treatment. However, teh cure rate decreases with age.

ChronicLeukemia

• ChronicLymphoblastic Leukemia (CLL):

CLL often progresses slowly and may not require treatment initially. While it is not always considered curable, many patients live long lives with effective management.

• Chronic Myeloid Leukemia (CML)

Targeted therapies, like tyrosine kinase inhibitors (TKIs), have transformed CML into a manageable condition for most patients, with some achieving remission that is close to a cure.

Factors influencing cure rates

• Advancements in Treatment: 

New therapies, such as CAR-T cell therapy and targeted drugs, have improved the outcomes for many leukemia types.

• Bone marrow transplantation:

For some, this can offer a chance at a complete cure.

• Early diagnosis:

Catching leukemia early increases the likelihood of successful treatment.

Conclusion: 

Leukemia is a complex disease with outcomes that vary based on its type, the patient’s age, overall health and how early it is detected. While some forms, like Acute Lymphoblastic Leukemia (ALL) in children, have high remission rates, others may be more challenging to treat.  Advancements in medical treatments, including chemotherapy, targeted therapies, and bone marrow transplants, have significantly improved survival rates. However, achieving a complete cure can be difficult, and some patients may experience relapses. Early diagnosis and personalized treatment plans are crucial for improving the chances of remission and long-term survival,

Citations

Leukemia. American Cancer Society. (n.d.). https://www.cancer.org/cancer/types/leukemia.html 

Leukemia: Symptoms, signs, causes, types & treatment. Cleveland Clinic. (2024, August 7). https://my.clevelandclinic.org/health/diseases/4365-leukemia 

Mayo Foundation for Medical Education and Research. (2024, December 20). Leukemia. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/leukemia/symptoms-causes/syc-20374373#:~:text=Leukemia%20is%20cancer%20of%20the,are%20more%20common%20in%20children 

Stages of leukemia. moffitt. (n.d.). https://www.moffitt.org/cancers/leukemia/diagnosis/stages/#:~:text=Leukemia%20cells%20develop%20within%20the,and%20platelets%20within%2  

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