Leukaemia

Overview of leukaemia

One common types of malignancies affecting millions worldwide is Leukaemia. It can attack people of any age group or ethnic group and is normally fatal in nature. The rise in the count of leukaemia cases and reported deaths has alarmed global health organizations. According to annual reports of American Cancer Society, about 11860 death cases were reported in the year 2016 due to different types of Leukaemia.

Malignancies have become a major cause of morbidity and mortality in the recent years. According to statistics of UK Cancer Research Organization, 14.1 million cases of cancer were reported in the year 2012, out of which 8.2 million resulted in death. Survival rates in acute cases of malignancy are very low.

Definition of Leukaemia

Leukaemia is the acute pathological condition in which abnormal cell growth takes place in the bone marrow (spongy tissue found within bones), which then spreads via circulating blood to other parts of the body.

In this condition, the bone marrow is infested with abnormal cells and has insufficient space for the development of healthy red blood cells, white blood cells, and platelets.

Leukaemia gives rise to three main clinical conditions –

• Anaemia (due to drop in Red Blood Cell count)
• Neutropenia (due to shortage of White Blood Cells)
• Thrombocytopenia (due to lack of platelets)

Depending on the type of blood-forming cell giving rise to Leukaemia, it can be of two types- lymphoid leukaemia and myeloid leukaemia.

Causes of Leukaemia

Leukaemia conditions may arise due to various extrinsic and intrinsic factors, which are discussed below-

• DNA damage: Destruction or mutation of DNA of White Blood Cells due to various factors cause activation of oncogenes (cancerous genes) and deactivation of tumor suppressor genes (cancer-preventing genes) and lead to Leukaemia.
• Radiation: Unprotected exposure to harmful radiations (ionizing or non-ionizing) during different diagnostic tests such as imaging, or radiotherapy to treat existing diseases can lead to Leukaemia in future.
• Chemicals: Toxicity induced by certain chemicals such as benzene, mercury, cadmium etc can cause Leukaemia in patients who are exposed to these chemicals on a regular basis (due to occupational hazards).
• Viral infections: Past infection with Human T-cell Lymphoma Virus-1 (HTLV-1) can cause lymphocytic leukaemia.
• Heredity: Few inherited syndromes such as Down syndrome, Klinefelter syndrome or Neurofibromatosis can predispose an individual to Leukaemia.
• Auto-immune disorders: Immune suppression can lead to abnormal cell growth within the body, increasing the risks of Leukaemia.
• Blood disorders: Certain blood diseases such as Thrombocythemia and Myelofibrosis increase the possibilities of Acute Myeloid Leukaemia.
• Substance abuse: Addictive habits like excessive cigarette smoking or alcoholism can damage different organs of the body leading to Leukaemia.

Few other common causes may include exposure to electromagnetic radiation (due to proximity to power grids), direct contact with harmful chemicals such as diesel, gasoline or pesticides.

Symptoms of Leukaemia

Different types of Leukaemia present different symptoms. The generalized symptoms are presented below-

• Abdominal swelling due to aggregation of Leukaemia cells in the spleen and liver
• Swollen lymph nodes due to spread of cancerous cells in those regions
• Acute joint pain due to accumulation of Leukaemia cells on the bone surface
• Shortness of breath due to spread of leukaemia cells to lungs and bronchi
• Headache, fatigue, seizures, nausea, vomiting, vision impairment and overall body imbalance due to intrusion of Leukaemia cells into the Central Nervous System
• Frequent bleeding from the nose and gums
• Frequent bruising which takes a long time to heal
• Perspirations at night
• Fever and general body ache
• Loss of appetite and abnormal weight loss
• Persistent infections
• Minute reddish spots under the skin
• Abnormal hair loss

Types of Leukaemia

Different classifications of Leukaemia are done based on different criteria. The first classification is done based on the degree of infection-

• Acute Leukaemia: It is caused by an accumulation of excess immature leukaemia cells which reproduce quickly.
• Chronic Leukaemia: It is caused by partially matured leukaemia cells which impede the body’s capacity to fight infections. These types of Leukaemia are difficult to cure.

Another classification is done based on the type of blood-forming cell giving rise to Leukaemia-

• Myeloid Leukaemia: It initiates in the immature forms of myeloid cells (RBC, WBC, and platelets).
• Lymphocytic Leukaemia: It starts in immature lymphocytes and spreads to other regions.

Combining the above classifications, the following classification has been proposed-

• Acute myeloid and lymphoblastic Leukaemia: In this condition, the original leukaemia cells rapidly multiply and form more leukaemia cells. These cells are themselves non-functional and impede the development and normal functioning of other healthy cells inside the bone marrow.
• Chronic myeloid leukaemia (CML): It is characterized by a drop in the count of Red Blood Cells (RBC) leading to anemia and an abnormal increase in the number of White Blood Cells (WBC).
• Chronic lymphocytic leukaemia (CLL): In this condition, an excess amount of non-functional lymphocytes are produced which rapidly replace the normal healthy cells in the bone marrow and lymph nodes. This disrupts the normal functioning of the healthy cells leading to loss of body’s immunity.

Vulnerable groups

Few individuals are more susceptible to Leukaemia conditions than others. The following vulnerable groups have been identified so far-

• Infants between 2 to 5 years of age
• Adults above 45
• Males are more prone to Acute Myeloid Leukaemia than females
• Aged people
• African American people

Diagnostic tests

For proper treatment of Leukaemia, accurate and detailed diagnosis is mandatory. The following diagnostic tests are recommended by oncologists-

• Blood tests (complete blood count and coagulation tests)
• Bone marrow tests (bone marrow aspiration and biopsy)
• Chromosome testing (to detect chromosomal aberrations)
• Lumbar puncture (to detect spread of cancer cells into the brain and spinal cord)
• Lymph node biopsy
• Imaging tests ( X-rays, CT scan, MRI scan) 

Treatment

The treatment course of leukaemia depends upon a number of factors such as type of leukaemia, age and health of the patient and many more. But the most important factor is whether or not the disease has spread to the cerebrospinal fluid. Chemotherapy is the most widely practiced treatment method for this condition. Other treatment methods include radiation therapy, targeted therapy, and stem cell transplant. If the spleen becomes enlarged due to leukaemia, then it has to be surgically removed. If the condition is chronic, the chances of complete cure are minimal. Treatment and medications can help manage the symptoms.

Close monitoring of the progression of the disease becomes helpful in understanding and diagnosing the spread of the disease. While there are no definitive preventive measures for leukaemia, maintaining a safety around artificial ionizing radiation, benzene and other dangerous chemical, deadly pathogens such as HIV and HTLV, and tobacco can be helpful.

Unfortunately, Leukaemia or any kind of acute cancer cases do not have a complete cure, although survival period of patients may vary. In most cases of Leukaemia bone marrow transplants and chemotherapy are recommended by the oncologists. But both the treatments techniques are expensive and cannot be afforded by the majority of the Leukaemia patients in low and middle-income countries. Global health organizations are working on promoting advanced treatments to increase the life-expectancy of cancer patients in general.

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