Symptoms
Leukemia affects cells responsible for immune function, blood clotting, and transportation
of oxygen. Symptoms relate to problems with these cells functions.
- Fatigue
- Shortness of breath
- Pale skin
- Mild fever
- Night sweats
- Excess bleeding
- Slow healing of cuts
- Bruising for no reason
- Red spots under skin
- Aches in bones/joints
- Low white blood cell count
Description
Leukemia is a group of cancerous diseases affecting the blood and lymph tissues.
There are four main types of leukemia:
- Acute lymphocytic leukemia (ALL)
- Acute myelocytic leukemia (AML)
- Chronic lymphocytic leukemia (CLL)
- Chronic myelocytic leukemia (CML)
In all four types, white blood cells developing in the bone marrow do not mature
correctly making them leukemic cells. Two groups of cells produced by the bone marrow
are affected; myeloid cells and lymphocyte cells. Myeloid cells are responsible
for forming red blood cells, some types of white blood cells, and platelets. Lymphocyte
cells form an important part of the immune system. The leukemic cells replace or
suppress the development of normal cells.
Acute leukemia affects young cells. Chronic leukemia affects mature cells. Acute
lymphocytic leukemia is most common in children with prevalence in the 2-5 year
age group. The other groups of leukemia tend to develop in an older population between
the ages of 50-75. Only 2% of chronic leukemia victims are children.
Causes
The cause of leukemia is still unknown. For some types of leukemia, risk factors
have been identified; for others, more research is needed.
Acute Lymphocytic Leukemia
This type of leukemia is most common in children. Risk factors are thought to be
a mix of environmental factors mixed with a family history of the disease. One theory
suggests that excess hygiene causes children to be protected from normal childhood
infections, which could give them a predisposition to the disease. Only 5% of cases
are linked to an inherited genetic syndrome. Often, previously healthy children
with none of these risk factors will present with the disease.
Acute Myelocytic Leukemia
Although common in all ages, this disease is more prevalent in people over 65 years
old. Myelocyctic leukemia has a group of identified specific risk factors. Exposure
to ionizing radiation, drugs that damage DNA makeup, and two types of chemotherapy
have been linked to disease development.
Chronic Lymphocytic Leukemia
Disease incidence is rare in people under 50 years old. Speculated risk factors are
family history and exposure to radiation/chemicals, although no concrete evidence
yet exists proving these links.
Chronic Myelocytic Leukemia
Affecting only 1-2 persons per 100,000, this type of leukemia is rare. Incidence
is higher in men, with women having a better survival rate. Although research has
identified that a gene translation causes the leukemia, what exactly spurs this
change is still unknown. As with other leukemia, a genetic and radiation factor
is thought to exist.
Treatment
Acute Lymphocytic Leukemia
As the disease is acute, treatment is started promptly after diagnosis. Initial treatment,
called induction therapy, usually consists of combination chemotherapy delivered
intravenously along with steroids. Common chemotherapies used are vincristine (Oncovin*)
and asparaginase (Elspar*), with the steroid dexamethasone (Tobradex*). After the
initial phase of treatment, therapy is continued in the consolidation and maintenance
stages to prevent relapse. Methotrexate (Rheumatrex*) is another chemotherapy drug
often used for these stages. Treatment can continue up to 2-3 years after diagnosis,
depending on whether the person is male or female. Bone marrow transplant is considered
if chemotherapy is unsuccessful.
Acute Myelocytic Leukemia
Treatment is carried out in two phases. The induction phase aims to achieve complete
remission. This is completed through using a combination of chemotherapy drugs such
as daunorubicin (Cerubidine*) and cytarabine liposome (DepoCyt*). In the consolidation
phase, often cytarabine is used. Stem cell transplantation is also considered, depending
on what type of gene mutation caused the leukemia.
Chronic Lymphocytic Leukemia
Due to new drug developments, the treatment of this chronic leukemia now mimics that
of the acute leukemia. Induction and consolidation phases can be effective. Purine
analogues, such as fludarabine, is often combined with rituximab (Rituxan*) in the
induction phase. Response and complete remission rates are high.
Chronic Myelocytic Leukemia
This chronic cancer is often first treated with a drug called imatinib (Gleevec*).
The drug works by turning off the enzyme that causes the cells to become cancerous.
If unsuccessful, stem cell transplantation is considered.