INTRODUCTION
Leukemia is cancer of the white blood cells. White blood cells help your body fight infection. Your blood cells form in your bone marrow. In leukemia, however, the bone marrow produces abnormal white blood cells. These cells crowd out the healthy blood cells, making it hard for blood to do its work.
The word "acute" in acute lymphocytic leukemia comes from the fact that the disease progresses rapidly and creates immature blood cells, rather than mature ones. The word "lymphocytic" in acute lymphocytic leukemia refers to the white blood cells called lymphocytes, which ALL affects. Acute lymphocytic leukemia is also known as acute lymphoblastic leukemia.
ALL is the most common childhood cancer. Children younger than age 5 have the highest risk. It can also occur in adults.
Acute lymphocytic leukemia can also occur in adults, though the chance of a cure is greatly reduced.
There are two main subtypes of ALL, B-cell ALL and T-cell ALL. Most types of ALL can be treated with a good chance of remission in children. Adults with ALL don’t have as high of a remission rate, but it’s steadily improving.
What happens in acute lymphoblastic leukaemia?
All of the blood cells in the body are produced by bone marrow, a spongy material found inside bones.
Bone marrow produces specialized cells called stem cells, which have the ability to develop into three important types of blood cells:
Red blood cells – which carry oxygen around the body
White blood cells – which help fight infection
Platelets – which help stop bleeding
Normally, bone marrow doesn't release stem cells into the blood until they are fully developed blood cells. But in acute lymphoblastic leukemia, large numbers of white blood cells are released before they are ready. These are known as blast cells.
As the number of blast cells increases, the number of red blood cells and platelet cells decreases. This causes the symptoms of anemia, such as tiredness, breathlessness and an increased risk of excessive bleeding.
Also, blast cells are less effective than mature white blood cells at fighting bacteria and viruses, making you more vulnerable to infection.
Symptoms of acute lymphoblastic leukaemia
Acute lymphoblastic leukaemia usually starts slowly before rapidly becoming severe as the number of immature white blood cells in your blood increases.
Most of the symptoms are caused by the lack of healthy blood cells in your blood supply.
Signs and symptoms of acute lymphocytic leukemia may include:
- Weakness or feeling tired.
- Fever.
- Easy bruising or bleeding.
- Bleeding under the skin.
- Shortness of breath.
- Weight loss or loss of appetite.
- Pain in the bones or stomach.
- Pain or a feeling of fullness below the ribs.
- Painless lumps in the neck, underarm, stomach, or groin.
Make an appointment with your doctor or your child's doctor if you notice any persistent signs and symptoms that concern you.
Causes & risk factors of acute lymphoblastic leukaemia?
It is a genetic change (mutation) in the stem cells that causes immature white blood cells to be released into the bloodstream.
Acute lymphocytic leukemia occurs when a bone marrow cell develops errors in its DNA.
The errors tell the cell to continue growing and dividing, when a healthy cell would normally stop dividing and eventually die. When this happens, blood cell production becomes abnormal. The bone marrow produces immature cells that develop into leukemic white blood cells called lymphoblasts. These abnormal cells are unable to function properly, and they can build up and crowd out healthy cells.
It's not clear what causes the DNA mutations that can lead to acute lymphocytic leukemia. But doctors have have identified a few risk factors of the condition.
Hispanics and Caucasians have shown a higher risk for ALL than African-Americans.
Males have a higher risk than females.
Previous cancer treatment. Children and adults who've had certain types of chemotherapy and radiation therapy for other kinds of cancer may have an increased risk of developing acute lymphocytic leukemia.
Exposure to radiation. People exposed to very high levels of radiation, such as survivors of a nuclear reactor accident, have an increased risk of developing acute lymphocytic leukemia.
Genetic disorders. Certain genetic disorders, such as Down syndrome, are associated with an increased risk of acute lymphocytic leukemia.
Having a brother or sister with ALL. People who have a sibling, including a twin, with acute lymphocytic leukemia have an increased risk of ALL.
Diagnosis of acute lymphocytic leukemia
Tests and procedures used to diagnose acute lymphocytic leukemia include:
Physical examination: Your doctor must complete a full physical exam and conduct blood and bone marrow tests to diagnose ALL. They’ll likely ask about bone pain, since it’s one of the first symptoms of ALL.
Blood tests. Blood tests may reveal too many white blood cells, not enough red blood cells and not enough platelets. A blood test may also show the presence of blast cells — immature cells normally found in the bone marrow.
Bone marrow test. During bone marrow aspiration, a needle is used to remove a sample of bone marrow from the hipbone or breastbone. The sample is sent to a lab for testing to look for leukemia cells.
Imaging tests. Imaging tests such as an X-ray, computerized tomography (CT) scan or ultrasound scan may help determine whether cancer has spread to the brain and spinal cord or other parts of the body.
Spinal fluid test. A lumbar puncture test, also called a spinal tap, may be used to collect a sample of spinal fluid — the fluid that surrounds the brain and spinal cord. The sample is tested to see whether cancer cells have spread to the spinal fluid.
Treatment of acute lymphocytic leukemia
Acute lymphoblastic leukaemia is an aggressive condition that develops rapidly, treatment usually begins a few days after diagnosis.
Treatment is usually carried out in the following stages:
Induction therapy. The purpose of the first phase of treatment is to kill most of the leukemia cells in the blood and bone marrow and to restore normal blood cell production.
Consolidation therapy. Also called post-remission therapy, this phase of treatment is aimed at destroying any remaining leukemia in the body, such as in the brain or spinal cord.
Maintenance therapy. The third phase of treatment prevents leukemia cells from regrowing. The treatments used in this stage are often given at much lower doses over a long period of time, often years.
Preventive treatment to the spinal cord. During each phase of therapy, people with acute lymphocytic leukemia may receive additional treatment to kill leukemia cells located in the central nervous system. In this type of treatment, chemotherapy drugs are often injected directly into the fluid that covers the spinal cord.
Other treatments you may need include antibiotics and blood transfusions. In some cases, a bone marrow transplant may also be needed to achieve a cure.
Complications of acute lymphoblastic leukaemia & outlook
Complications
If a cure for acute lymphoblastic leukaemia isn't possible, there's a risk that the lack of healthy blood cells can make the person:
Extremely vulnerable to life-threatening infections (because of the lack of white blood cells)
Prone to uncontrolled and serious bleeding (because of the lack of platelets)
Outlook
The outlook for children with acute lymphoblastic leukaemia is usually good. Almost all children will achieve remission (a period of time where they're free from symptoms), and 85% will be completely cured.
The outlook for adults with acute lymphoblastic leukaemia is less promising. Around 40% of people aged between 25 and 64 will live for five years or more after receiving their diagnosis. In those aged 65 or over, around 15% will live for five years or more after being diagnosed.
