types of leukemia
detection of leukemia
special tests in leukemia
is leukemia always fatal?
treatment of leukemia
future hope in leukemia

Leukemia is cancer of the blood. It is common cancer, that affects people of all ages. This article is a brief account of this dangerous but treatable disease.

Is leukemia of one type only?

No. Leukemia can be classified into acute and chronic. The onset of acute leukemia is rapid and if untreated death occurs within 3 to 6 months. Chronic leukemia, on the other hand, sets in slowly and death, even in untreated patients, occurs in 2 to 10 years or sometimes later.

Acute leukemias are further classified into:
  Acute myeloid leukemia (AML)
Acute lymphocytic leukemia (ALL)
Chronic leukemias are further classified into:
  Chronic myeloid leukemia (CML)
Chronic lymphocytic leukemia (CLL)

There are many subtypes of each of these 4 major varieties and the outlook is highly variable.

Another form of blood cancer is referred to as multiple myeloma.


How is leukemia detected?

Leukemia is diagnosed on the basis of its clinical features and laboratory tests.

Clinical features. Depending on the type of leukemia presentation is highly variable and ranges from fever, weakness, and loss of weight. In acute leukemia there may be bleeding into skin or bleeding from nose, mouth or intestine. Chronic leukemia may, on the other hand, present with dragging sensation or a mass in the abdomen due to enlargement of spleen.
Symptoms of acute and chronic leukemias are also seen in several common disorders. Therefore, the patients should not presume that presence of any of these symptoms is definite evidence of leukemia.

Laboratory features: Leukemia may be detected through a routine blood test. In leukemia the precursors (parent cells) of the blood cells, that in healthy state remain in the bone marrow, may get released into blood. The white cell counts are often markedly increased. The diagnosis rests on finding that most of these cells are immature (i.e. they resemble parent cells) and not mature cells. Some immature cells are also found in blood in many non-malignant conditions especially infections. Therefore, presence of immature cells in blood is not a definite evidence of leukemia.

In some cases immature cells do not appear in the peripheral blood and examination of bone marrow is required to make a diagnosis. Bone marrow examination is often necessary to determine exact type of leukemia by special tests and extent of disease. The bone marrow shows proliferation (increase) in primitive (parent) cells of blood. These primitive cells differ from normal cells and can be identified by routine techniques or by special procedures.

The cancer (leukemic) cells have a growth advantage over normal blood-forming cells. The bone marrow and blood, therefore, get packed with the cancer cells with concomitant decrease in normal marrow and blood cells. Most of the effects on body are due to reduction in normal cells in the blood. The blood test, thus, shows a fall in red cells, normal white cells and platelets along with presence of immature cells in the blood. Fall in red cells is detected by a fall in hemoglobin (Hb) level. This results in anaemia. The fall in normal white cells impedes defense mechanism. Resistance of the body to infection is markedly reduced. Platelets are necessary to control bleeding. A fall in platelets often leads to spontaneous bleeding. This may be life threatening if blood loss is high or if bleeding occurs in vital organs such as brain.


What special tests are required to determine the type of leukemia?

Special tests consist of (i) cytochemical stains (ii) cytogenetic studies to determine chromosomal pattern and (iii) immunochemistry/immunophenotyping. These help in clearly defining the precise nature of the cell from which the cancer arises. Some other tests such as genetic markers can also be studied but are generally not required. The special tests are performed in specialised laboratories as they are expensive and need expertise to interpret results.

Special tests are necessary because the treatment and prognosis markedly differ with the type and subtype of leukemia. For example for most types of acute lymphocytic leukemia (ALL), chemotherapy is the treatment of choice while for some types the preferred treatment is bone marrow transplantation.

In general, the prognosis of acute myeloid leukemia (AML) is influenced by its genetic pattern and that of ALL with immunophenotypic and cytogenetic patterns. The treatment of leukemia is unfortunately expansive and requires expertise. The special tests no doubt add to the cost but benefits derived in many patients outweigh the additional expense of about five per cent of the total cost.


Is leukemia always fatal?

No. The prognosis of leukemia has markedly changed and many forms of leukemia are curable? Somewhat paradoxically, the cure rate in acute leukemia is higher than in most forms of chronic leukemias. In one form of chronic leukemia referred to as "hairy cell leukemia' the prognosis is good.


What are the treatment modalities?

The treatment is highly specialized and for many patients requires hospitalization at suitable intervals. The primary modality is courses of combination chemotherapy i.e. administration of drugs by parenterally (by injection) or orally. These medicines kill not only cancer cells but also normal blood cells. Therefore, there is further fall in hemoglobin, white cells and platelets. The ill effects are controlled through (i) regulation of dose of anti-cancer drugs, (ii) replacement (transfusion) of specific products, (iii) administration of antibiotics and (iv) barrier nursing. The effects include fever (due to infections), diarrhea, bleeding, hair loss and kidney and liver damage. Many other serious complications can occur requiring expert management. Generally the courses of therapy are referred to as 'Remission induction', 'Consolidation' and 'Maintenance'. The courses are spread over about 2 years.

Some patients require drugs that induce immune response against leukemic cells. Other treatment modalities include radiotherapy and bone marrow transplantation. In India the bone marrow transplantation facilities are now available at (i) Christian Medical College Hospital, Vellore, Tamil Nadu, (ii) Tata Memorial Centre, Mumbai, Apollo Hospital, Chennai and All India Institute of Medical Sciences, New Delhi.

Psychological support for the patient and the family is required.

If one therapeutic regimen fails or the disease relapses, many patients respond to alternate regimens of drugs.


Future hope

Several groups are conducting intensive research to understand the nature of cancer and find new therapies. Every year new medicines are introduced which are more effective and have fewer side effects. Drugs are being attached to molecules that will reach the cancer cells and spare the normal cells. Alternatives to bone marrow transplantation are also emerging. It is hoped that in the next two to three years several new modalities will be commercially available.



Dr Swaroop K Sood, , MD (AIIMS), is the head of Pathology services at Sir Ganga Ram Hospital. Formerly Associate Professor of Pathology at the All India Institute of Medical Sciences, and later Professor and Head of Pathology, University College of Medical Sciences, Dr Sood has a special interest in Hematology. He has had an active academic career and has published several papers in national and international journals.
Contact Nos: 6434260, swaroopksood@hotmail.com

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Last revised: May 12, 2000