Leukaemia

Leukaemia is one of the top ten killer cancers in Hong Kong. It is also the top three common newly diagnosed cancer in children and adolescents. Unlike most other cancers, leukaemia occurs in both adult and children.

(Special thanks to Dr. June LAU, Consultant, Department of Medicine, Queen Elizabeth Hospital for reviewing the information of this page.)

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Hematological cancers originate from blood cells, bone marrow cells or lymphocytes, and can be divided into chronic and acute subtypes. Some hematological cancers have no visible symptoms and different types of hematological cancers have different symptoms, symptoms may be ignored resulting in diagnosis at a later stage. Different types of hematological cancers have different treatment methods; some require emergency treatment, and if treatment is delayed, it can have serious consequences and can be life-threatening; while others only need to be monitored regularly and wait until there is indication for treatment.  Therefore, based on the uniqueness of each disease and the different physical conditions of the patient, doctors will discuss with patients on a suitable plan of management.
There are three main categories of blood cancers: leukemia, lymphoma, and multiple myeloma. Within these three categories, there are also a variety of diseases.
Hematopoietic system
Bone marrow is a sponge-like tissue located within bone cavities.
Bone marrow is the factory that produces blood cells. The most primitive hematopoietic stem cells produce red blood cells, white blood cells and platelets. This is called the hematopoietic system.
All types of blood cells have different lifespans and are constantly renewed (red blood cells: 120 days, white blood cells: 1-2 days, platelets: 8 days).
The treatment of many hematological cancers, their related side effects and the disease itself may have varying degrees of impact on the hematopoietic system.


Leukemia
Leukemia usually occurs in the bone marrow, production of abnormal cells during cell growth.
Cytopathy causes a massive proliferation of abnormal cells. These immature white blood cells become blood cancer. The abnormal cells may also suppress the normal bone marrow hematopoietic function.
Leukemia can be divided into two types: myeloid and lymphoid, depends on whether the origin of abnormal cells is from bone marrow (myeloid leukemia) or w from lymphoid system (lymphocytic leukemia).
In addition, it can be divided into two types: acute and chronic. Under normal circumstances, the bone marrow contains a small number of immature cells, called blastocytes. The mature blastocytes will turn into white blood cells, red blood cells, and platelets and be released into the blood vessels.
Acute Leukemia
The excessive proliferation of abnormal blastic cells (blood cancer cells) in the bone marrow suppresses the normal bone marrow hematopoietic function and seriously affects body functions. Blood cancer cells will also squeeze into the blood system and circulate in the body. Acute leukemia develops rapidly, so it must be treated as early as possible.
Common acute leukemias include:
1) Acute myeloid leukemia (AML)
2) Acute lymphoblastic leukemia (ALL)
 
Chronic Leukemia
The bone marrow accumulates too many abnormal, immature white blood cells and cannot function normally, which also affects normal hematopoiesis. However, early chronic leukemia usually develops more slowly and even has no symptoms.
 
Common chronic leukemias include:
1) Chronic lymphocytic leukemia (CLL)
2) Chronic myelogenous leukemia (CML)
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The exact cause of leukemia is not known, but some conditions increase the risk:

  • For people over 65 years old, the risk increases with age
  • Exposure to large amounts of environmental radiation
  • Have received certain anti-cancer drug treatments in the past
  • Long-term exposure to chemicals: such as benzene and its derivatives
  • Viral infection
  • Smoking
  • Related to genetic inheritance: such as Down syndrome
  • History of other blood disorders, e.g. myelodysplasia
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Normal hematopoiesis is affected in patients with leukemia. Patients may have the following symptoms:

  • Insufficient normal white blood cells increase the chance of infection: oral inflammation, sore throat, burning pain during urination, fever, chills, night sweats. Severe infection can result in pneumonia and septicemia.
  • Insufficient red blood cells causing anemia: pale looking, dizziness, palpitations, fatigue and shortness of breath.
  • Insufficient platelets make it easy to bruise and bleed: the skin may bruise or bleed for no apparent reason. Women may have increased or non-stopped menstrual bleeding.  Bleeding sites include nose, gums, stool, urination, etc., or even cerebral hemorrhage.
  • Other symptoms: bone pain, headache, chest pain, vomiting, worsening of vision, swollen lymph nodes, enlarged spleen, weight loss. Some patients, especially those with chronic leukemia, may have no symptoms at all and may not notice any abnormalities until physical examination.
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Although patients may have various symptoms, the diagnosis of leukemia can only be confirmed through laboratory tests. Doctors will also formulate treatment plan according to physical condition of the patients. In general, the following tests will be arranged:
 
Blood test
Complete blood counts, including testing for abnormal white blood cell, red blood cell and platelet counts, smear tests, liver and kidney function tests and viral tests such as hepatitis B.
 
Bone marrow aspiration and trephine biopsy
Bone marrow blood and a small bone section are extracted from the patient's pelvis and analyzed by the laboratory to find out whether there are abnormal cells or chromosomes with pathological changes, so as to select appropriate treatment. The procedure is performed under local anesthesia in a ward or day ward. Patients are advised to have bed rest after the procedure so as to help stop bleeding.

Throughout the course of leukemia treatment, bone marrow examinations are repeated at regular interval to check for effectiveness of the treatment.  Based on the bone marrow results and condition, doctors will decide whether to continue the chemotherapy plan or whether treatment strategy has to be revised.
 
Gene and chromosome analysis
Analyze the genetic and chromosomal variations of blood cells or bone marrow cells, such as "Philadelphia disease", to understand the cause of the disease, and help determine treatment plan and prognosis assessment.

Spinal tap
The doctor will insert a fine needle into the patient's spine at lower back to extract cerebrospinal fluid and check whether there is invasion of diseased cells in the central nervous system. It is mainly done in patients with acute lymphoblastic leukemia and chemotherapy is usually injected at the same procedure. After the examination, patients need to rest in bed to reduce discomfort.

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Acute leukemia is mainly treated with chemotherapy, steroids, radiotherapy and, if necessary, peripheral stem cell or bone marrow transplantation.
 
Chemotherapy
Use anti-cancer drugs to kill cancer cells and stop them from multiplying. Different chemotherapy treatments will have different side effects. The treatment and effects of chemotherapy are systemic. During the process, not only cancer cells are eliminated, normal cells are also eliminated to different extent. This may result in various side effects.
Chemotherapy can be divided into three stages:

  1. Induction chemotherapy
           To achieve remission, which means there are no signs of blood cancer cells in the bone marrow and blood
  1. Consolidation chemotherapy
          When remission is achieved, treatment will enter consolidation phase, which lasts for 4-8 cycles, depending on the type of disease
  1. Maintenance chemotherapy

           Maintain remission and reduce the chance of relapse
 
In addition to intravenous infusion, chemotherapy drugs are sometimes injected into patients in need through spinal route to prevent disease spreading to the central nervous system or to treat diseases in the brain or spinal cord. In addition, radiation therapy to the head is sometimes given.
 
During chemotherapy, if the effect is not satisfactory, the doctor will evaluate the situation and switch treatment to another chemotherapy regimen until the disease is controlled or even eliminated. Due to the long course of treatment and the possibility of complications, patients need to undergo frequent blood tests. The patient may need to receive blood transfusions or other blood products, such as platelets, or may need to be hospitalized and receive medication such as antibiotics.
 
To avoid damage to blood vessels and repeated needle insertion, patients are usually asked to have a central venous catheter implanted in the chest or arm to reduce the pain caused by repeated blood taking and intravenous injections.
 
Steroid treatment
Steroids are often used along with chemotherapy.
 
Radiation therapy
Radiation therapy is less commonly used to treat acute leukemia. If needed, it is often used to irradiate the head before allogeneic stem cell transplantation. The length of the treatment depends on the patient's physical condition. Generally, the patient receives five to ten irradiations within one or two weeks. Side effects of radiation therapy include nausea, vomiting, fatigue, changes in taste and smell, drowsiness, hair loss, etc. Most side effects are temporary and symptoms improve with time. However, some of them may be permanent.
 
Peripheral blood stem cell or bone marrow transplant
For higher-risk leukemia patients, after the disease is in remission, doctors may recommend peripheral blood stem cell or bone marrow transplantation based on the risk of relapse, age, availability of suitable bone marrow donors, and health status.

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Diagnosis of leukaemia is often devastating for both the patient and his/her family. While it is difficult to avoid focusing on the treatment relating complications and possibility of dying, it is important for patient and his/her family to remember that many patients can have good control and cure with treatment available today. 
 
There is some practical support that may help you and your family fight the leukaemia in a positive way:
 
  • Take medicines regularly: Patient should know the dosage and potential side effects of various medications (chemotherapy drugs or antibiotics). Follow the instruction given by your doctor. Do not stop medication on your own.
  • Regular follow-up: After treatment, doctor will arrange regular examinations and blood tests to monitor patient's health status and blood cell count, and to detect recurrence as early as possible.
  • Diet: Cancer treatment might weaken the immune system. Immunocompromised patient is advised to avoid to eat raw or undercooked meat, poultry, eggs, seafood, raw or unpasteurized dairy products, and ready-to-eat raw vegetables.
  • Prevent infection: Cancer patient may have a higher risk of infection because of changes in the immune system after treatment. Patient should pay attention to home and personal hygiene, avoid going out in public, and remember to wear a mask.
  • Avoid contact with chickenpox patients: In case cancer patient is infected with chickenpox, he or she must be treated immediately, otherwise complications and mortality will be extremely high.
  • Prevent bleeding: Keep ideal humidity level at home to avoid nasal bleeding due to dryness; pay attention to daily safety to avoid injury.
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