Investigations in Leukemia

Introduction

Leukemia is a broad term for blood cancer. When the blood cells begin to proliferate uncontrollably and affect the functions of the normal blood cells, it is called blood cancer. The normal functions of red blood cells include fighting infections and producing new blood cells. Most cancers start in the bone marrow, where the red blood cells and platelets are produced. Leukemia commonly affects adults older than 55 years. However, it has recently been commonly seen in children younger than 15.

What Is Leukemia?

Cancer in the blood cells is broadly termed leukemia. Each type of leukemia is termed based on the type of blood cell affected and whether it grows slowly or fast. The predominant types of leukemia include acute myeloid leukemia (AML) and chronic myeloid leukemia (CML), acute lymphoblastic leukemia (ALL), and chronic lymphocytic leukemia (CLL). The lesser common ones include mature B-cell and T-cell leukemias and NK cell-related leukemias.

What Are the Types of Leukemia?

Leukemia is classified based on the type of cell involved and the speed of progression of the disease. Based on disease progression, it is classified into;

• Acute Leukemia: When the cells multiply fast, and the condition advances rapidly, it is called acute leukemia. It can be life-threatening and requires immediate treatment. The condition is most commonly seen in children.

• Chronic Leukemia: In this condition, mature and immature blood cells are in the body. It matures to an extent where it functions as a cell. However, the functions of a normal blood cell are not done. It advances slowly and is commonly seen in adults.

Based on the type of cell involved, it is classified as:

• Myeloid Leukemia: This type of leukemia develops from a type of blood cell called myeloid. The myeloid cells usually develop into red blood cells, white blood cells, and platelets.

• Lymphocytic Leukemia: They arise from lymphoid cells. The lymphoid cells mature into white blood cells, which helps in the body's immunity.

The four common types of leukemia include:

1. Acute Lymphocytic Leukemia (ALL): This is the most common type of leukemia that affects children, teens, and young adults.

2. Acute Myelogenous Leukemia (AML): It is the most common type of blood cancer among adults, especially those over sixty-five years.

3. Chronic Lymphocytic Leukemia (CLL): This is the most common type of blood cancer that is chronic in adults. There might not be any symptoms for many years during the initial stages of the disease.

4. Chronic Myelogenous Leukemia (CML): This is more common in older adults (older than sixty-five years) but also common in adults of all ages nowadays.

How Is Leukemia Diagnosed?

• Physical Examination: This is the first method of testing when a patient is suspected of leukemia. The early warning signs of the condition can include fever, chills, fatigue, loss of appetite, weight loss, night sweats, headache, shortness of breath, etc. Other possible signs include anemia, leukopenia (a decrease in functional white blood cells), thrombocytopenia (a low platelet count), swollen lymph nodes, and an enlarged liver or spleen. A physical examination may focus on checking for swollen lymph nodes or enlargement of the spleen or the liver. Signs of infection or bruises are also checked, as it is an important warning sign of leukemia.

• Blood tests and Other Laboratory Tests: Some types of leukemias, like chronic lymphocytic leukemia, can be confirmed by a blood test. However, more tests would be required to know more about the condition. The most commonly done blood tests can include;

  • Complete Blood Count (CBC): This test counts the number of white blood cells, red blood cells, and platelets in the body.

  • Differential Blood Count: This test analyses the different types of white blood cells in a person's body.

  • Peripheral Blood Smear: This test helps to analyze the different stages of the blood cell in a person's body. A person with leukemia will have more immature blood cells than mature cells that are functional.

The different blood test shows different results for each type of leukemia. The blood test for AML shows high levels of immature white blood cells and fewer red blood cells and platelets. Myeloblasts are found in the blood and are not usually seen in ordinary people. The result of a person with CLL shows an increase in the number of lymphocytes, which are abnormal and immature. CMl shows a high number of abnormal myeloblasts. ALL shows an increased number of immature lymphocytes.

1. Flow Cytometry: This test provides details on the DNA (deoxyribonucleic acid) of the tumor cells and the growth rate of the tumor cells. It helps to diagnose the exact type of leukemia. It also provides details on the rate of progression of the cancer cells.

2. Biopsy: The type of leukemia, the growth rate of the tumor and the spread of the disease can be diagnosed by a biopsy. The standard biopsies for leukemia include bone marrow aspiration, bone marrow biopsy, and lymph node biopsy.

3. Imaging Techniques: It helps to determine the extent of leukemia in the body. Some kinds of leukemia require a constant chest X-ray to check for lung infections. Other imaging modalities used to diagnose leukemia can include CT scan, positron emission tomography (PET) scan, MRI scan, ultrasound, 2D echocardiogram, etc.

4. Pulmonary Function Test: This assesses a patient's lung functions before and after the treatment. It helps the healthcare provider to know how strong a patient's lungs are and the effects of the treatment on the lungs. There are different tests done to check this. In a spirometry test, the patient is advised to breathe into a tube. The computer measures the air exhaled in every breath. Lung plethysmography checks the amount of air a patient breathes in when inhaled and then with what force they breathe out while exhaling. In a lung diffusion, the patient is asked to inhale a gas through a tube, wait a few seconds, and then exhale. The doctor examines exhaled air that is in the tube.

5. Lumbar Puncture: This test is also known as the spinal tap. It is also used to determine the extent of leukemia spread in the body.

6. Cytogenetic Analysis: This test helps to identify the genes that are affected. This is done by identifying chromosomal alterations.

7. Fluorescence in situ Hybridization (FISH): It can find abnormalities in a patient's genes and help to determine the proper treatment path.

Conclusion

Diagnosing leukemia in its early stages helps to improve the prognosis. It also increases the chances of recovery of the patient. Chronic leukemia progresses slowly, while acute leukemia grows fast. Cancer may appear and progress differently based on the type of leukemia.