Acute Lymphoblastic Leukaemia (ALL) also known as Acute Lymphocytic Leukaemia is a type of cancer of the blood and bone marrow – the spongy tissue inside bones where blood cells are made. Also referred to as Acute Lymphoid Leukaemia and/or Acute Lymphoblastic Leukaemia, it is characterised by an overproduction of immature white blood cells, called lymphoblast or leukemic blasts. Because the bone marrow is unable to make adequate numbers of red cells, normal white cells and platelets, people with ALL become more susceptible to anaemia, recurrent infections, and to bruising and bleeding easily. The blast cells can then spill out of the bone marrow into the bloodstream and accumulate in various organs including the lymph nodes, spleen, liver and central nervous system (brain and spinal cord). While ALL is the least common kind of cancer affecting adults, among children it is the most prevalent.
Presently, no screening tests have been shown to be helpful in finding acute myeloid leukaemia (AML) early. AML often develops and causes symptoms to surface fairly quickly. Therefore, the best way to find AML early is to report any possible symptoms of AML right away.
Certain groups of people are known to be at high risk of AML because they have certain blood disorders, such as a myelodysplastic syndrome or inherited disorders such as Down syndrome, or because they were treated with certain chemotherapy drugs or radiation.
AML can show up in the form of one or more of these symptoms:
- Easy bruising or bleeding
- Flat pinpoint red spots under the skin caused by bleeding
- Weakness or feeling tired
- Shortness of breath
- Weight loss
- Loss of appetite
- Night sweats
Many of these symptoms may occur simply because of a reduction in normal blood cells. So it is important to see a doctor for a conclusive diagnosis.
Most AML cases can’t be pinned down to exact causes. However, the following risk factors are usually associated with the disease:
- Smoking, especially after the age of 60
- Past history of chemotherapy or radiation therapy
- Having had treatment for childhood Acute Lymphoblastic Leukaemia or ALL
- Being exposed to radiation
- Exposure to benzene
- Having a myelodysplastic syndrome or a bone marrow failure disease
- Congenital syndromes like Down’s Syndrome
- Gender (more AML patients are male)
AML is diagnosed by a simple peripheral smear which requires a drop of blood and examination under microscope. A bone marrow aspiration or trephine biopsy follows. The aspirate helps in identifying blasts and special stains that differentiate other forms of acute leukaemia or from ALL.
A flow cytometry assessment and cytogenetics assessment for karyotype (chromosome arrangement patterns) using peripheral or bone marrow aspirate (preferable) will identify the immunophenotype of the AML and help in ascertaining prognosis.
The patient may need a lumbar puncture to assess spread to brain, if indicated.
Chemotherapy is the main treatment for most people with acute myeloid leukaemia (AML). Chemo is often not recommended for patients in poor health, but advanced age by itself is not a barrier to getting chemo. It is usually divided into two phases
- Induction Soon after diagnosis an intensive course of treatment begins to bring about, or induce, a remission. The goal is to clear the blood of leukaemia cells (blasts) and to reduce the number of blasts in the bone marrow to normal.
- Consolidation After induction therapy finishes and remission is achieved; more treatment is required to help destroy any leftover disease in your body. This helps prevent a relapse and/or a spread to the central nervous system. consolidation therapy chosen will depend on the estimated risk of relapse.
- A third, maintenance phase (or post-consolidation), involves giving a low dose of chemo for months or years after consolidation is finished. This is often used to ?treat acute promyelocytic leukemia (APL), but it is rarely used for other types of AML.
Further, in consolidation therapy, once the patient is in complete remission, allogenic transplant may be offered to patients upfront if they have poor cytogenetics, and after first relapse in standard risk patients.
Hematopoietic stem cell transplant is a therapy form, wherein an HLA matched donor’s stem cells are removed by peripheral vein puncture, using an apheresis machine and given to the patient after conditioning therapy. It is superior to autologous transplant, where the patient’s own stem cells are used.
In poor risk patient (those with unfavourable cytogenetics) allogenic transplant confers better survival after inducing first clinical remission than otherwise.
AML is a difficult disease to treat as it is very aggressive, and needs continuous monitoring and follow up. The single most important prognostic factor in AML cytogenetics or the chromosomal structure of the leukaemic cell. Certain cytogenetic abnormalities are associated with very good outcomes (for example, the (15;17) translocation in APML or AML M3). About half of AML patients have ‘normal’ cytogenetics. They fall into an intermediate risk group. A number of other cytogenetics abnormalities are known with a poor prognosis and a high risk of relapse after treatment.
Favourable outcome rates in clinical trials have ranged from 20 to 45%. However, it should be noted that clinical trials often include only younger patients and those able to tolerate aggressive therapies. The overall favourable outcome rate for all patients with AML (including the elderly and those unable to tolerate aggressive therapies) is likely lower. Favourable outcome rates for promyelocytic leukaemia can be as high as 80% – 90%.