Leukaemia: A reason to hope

"Thanks to new treatments and therapies which have increased the chances of survival, the outcomes of leukaemia have vastly improved over the past few years," says Professor Vernon Louw, head of the Clinical Haematology Unit in the Department of Internal Medicine at the University of the Free State.

Professor Louw says leukaemias - a type of cancer characterised by increased numbers of white blood cells - make up an estimated 2% of all cancer cases in the country. He says the lifetime risk of developing leukaemia is about 1 in 77 or 1,3%. The disease affects more men than women and more white people than other racial groups. The average age of people that are diagnosed with leukaemia is 66 years, with fewer than 11% of cases being diagnosed in people under 20 years of age.

Bone marrow - the body's 'blood factory'

The bone marrow is the body's blood 'factory' which continually manufactures blood cells in order to replace old cells and, in emergencies such as haemorrhage or infection, increases the production of these cells, explains Louw. "Most leukaemias cause an increase in white cell production and these eventually push out other healthy cells in the bone marrow, affecting the body's ability to produce other blood cells necessary for normal functioning."

There are many types of leukaemias, but they can be broadly defined as either acute or chronic.

"In acute leukaemias, the maturation process of cells is disrupted and immature cells, also known as blasts, flood the bone marrow," says Louw. "These cells are not yet fully useful and as they multiply rapidly, they displace healthy cells from the bone marrow, leading to a decrease in the production of other normal blood cells."

He also says, acute leukaemias develop rapidly and without treatment patients can die within a matter of days or weeks. In chronic leukaemias, cancerous cells mature slightly more than in acute leukaemias. These can be considered as "teenage" cells which are also still not fully functional. These types of leukaemias develop over months or years.

Because leukaemia affects the bone marrow, the production of new blood cells including red blood cells which carry oxygen from the lungs around the body; normal white blood cells which help the body defend itself against infection; and platelets, whose main function is to prevent bleeding, is affected, adds Louw.

Typical signs

Typical signs and symptoms of leukaemia include fatigue, easy bruising, bone or abdominal pain, swollen glands and weight loss. Patients can also become anaemic and experience fever, recurrent infections and abdominal swelling, says Louw.

"An early diagnosis is critical so it's important to see your doctor if you're experiencing any of these symptoms or if they persist. A person's chance of survival depends very much on the type of leukaemia and how early they are diagnosed," says Louw.

If a doctor suspects that a patient has leukaemia, Louw says a blood test will be taken and pathologists will examine a thin smear of blood to determine whether there are any abnormalities. Genetic tests are also sometimes conducted as some leukaemias can be caused by faulty genes.

"Blood cancers can alter the appearance of cells found in the blood or they can lead to an increase in some types of normal-appearing cells," says Louw. "If your white blood cell count is higher than the normal range, it could be a sign of leukaemia1."

He says the successful treatment of leukaemia requires eliminating all cancer cells. "Because most blood cancers represent disorders of rapidly dividing cells, treatments that kill these types of cells have been used successfully to treat many of these disorders, including chemotherapy and radiation."

Encouraging results

Louw says, ideally, chemotherapy drugs would destroy only cancer cells and not normal cells, minimising the adverse effects associated with the destruction of normal cells. However, up until now, no such drugs existed. "New generation targeted therapies are showing encouraging results in treating specific cancers more accurately," he says. "Stem cell transplants have also been successful in treating some types of leukaemias."

Nowadays, high-dose chemotherapy can be used to destroy all blood elements, before donor stem cells can be transfused into the patient. "This new marrow re-populates the patient's blood compartment and may lead to a cure," says Louw.

Louw says more than 10 million donors worldwide have registered on the world's stem cell databases, increasing the chances of a person finding a potential donor.

Although about 1 in 25 000 unrelated people are a 'match' for transplant purposes, a large number of donors registered in the banks worldwide, has increased the chances of a Caucasian person finding a donor to around 60 - 70%.

Try not to be afraid

"That's compared to the chance of your siblings being a suitable match at 25% for each sibling," says Louw. A transplant from a sibling donor is usually preferred above that of an unrelated donor, so doctors will try to test siblings first before searching stem cell banks. "Unfortunately there are fewer registered donors for other racial groups, thus reducing these patients' chances of finding a suitable match."

Louw says patients are often very afraid and confused when they are first diagnosed with leukaemia. "This shouldn't be the case. The best thing you can do is arm yourself with as much knowledge about the disease as possible," says Louw. "This will help to put you in a position where you're able to make informed decisions about your treatment options."

References:

1) Wujcik D. Leukemia. In: Yarbo CH, Frogge MH, Goodman M, eds. Cancer Nursing Principles and Practice. 6th ed. Sudbury, Mass: Jones and Bartlett Publishers; 2005; 1330-1354.