Cancer of the blood cells is called leukaemia. Bone marrow is where blood cells are formed. In leukaemia, immature blood cells multiply rapidly, live longer, and crowd out the healthy blood cells in the bone marrow.
Leukaemia incidence (like most cancer types) increases with age. This largely reflects cell DNA damage accumulating over time. It often affects adults older than 55 years, however it is also the most common cancer in children below 15 years. About 90% of all leukaemias are diagnosed in adults. Incidence rates are higher for males than females.
There are different types of leukaemia and it is important to identify each as treatment and prognosis differs widely. The 2 main types are Acute and Chronic leukaemia (depending on cell maturity and the ability of cancer cells to spread). Acute leukaemia consists of immature cells that reproduce rapidly, chronic leukaemia is made up of mature cells which reproduce slowly.
What causes Leukaemia?
There are several factors that can increase a person’s risk of getting leukaemia. For example,
- Exposure to radiation
- Previous exposure to chemotherapy drugs
- Exposure to certain chemicals eg. Benzene
- Genetic disposition in patients with Down’s syndrome
Symptoms and Diagnosis
During the early stages of leukaemia, there may be no symptoms. Many of the symptoms of leukaemia don’t become apparent until a large number of normal blood cells are crowded out by abnormal cancer cells.
Symptoms of acute disease are caused by bone marrow failure to produce normal blood cells. Main symptoms include fatigue (due to lack of RBCs), easy bruising and abnormal bleeding (due to lack of platelets), in addition to prolonged fever.
Other signs include loss of appetite, significant weight loss and pain in bone and joints. Discomfort in the abdomen may arise from an enlarged spleen and swollen lymph nodes are often detected, especially in the neck or armpit.
If left untreated, serious bleeds will occur in major organs eg. brain and the patient is prone to serious bacterial / fungal infections due to depressed immunity. Lack of RBCs will lead to shortness of breath and chest pain, eventually a heart attack.
Acute leukaemia which is not treated causes mortality.
Examination of the bone marrow is vital in providing the diagnosis. Samples are obtained from the hip bone in a procedure called ‘Bone Marrow Aspiration’, which is relatively safe and performed under local anaesthesia. The bone marrow slides are then examined under a microscope by a blood specialist in the lab. Other tests include collecting a sample of fluid around the brain and spinal cord by performing a spinal tap.
Computed tomography (CT) scans, and ultrasounds are tests may also be used to determine if leukaemia has spread from the bone marrow. With these tests, the doctor also looks for other abnormalities such as enlarged organs or signs of infection.
Treatment method depends on the type of leukaemia. Acute leukaemia requires intensive chemotherapy and often bone marrow transplant in high risk cases. The goal of treatment is to eliminate the cancer cells and allow the normal blood cells to grow and recover.
Chronic leukaemias can be controlled with medications. For instance, CML can be controlled using the drugs called ‘Tyrosine Kinase inhibitors’ which allow the patient to live longer, free from symptoms.
Treatment options for leukaemia are becoming safer and more effective after much research. With this, patients are living longer with hopes that the cancer can finally be cured in the future.