Acute Lymphocytic Leukemia

Basic Information

Acute Lymphocytic Leukemia (ALL) is a cancerous disorder that occurs in the bone marrow. In particular, it happens when there is rapid and uncontrollable production and build-up of infection-fighting white blood cells in the affected person. These white blood cells are also called lymphocytes. Lymphocytes are generated in the bone marrow and in other parts of the lymphatic system (such as the spleen which is responsible for generating and storing blood cells). The lymphatic system consists of a complex of organs and tissues, and it prevents diseases and infections from overwhelming the body's immune system. The lymph system is composed of a network of small tubes that are connected to all the body's major blood vessels. These small tubes allow lymph, a fluid that contains the lymphocytes, to move through the body. It is the lymphocytes in this lymph fluid that create antibodies, the chemicals that eradicate anything that invades the body's immune system.

Bone marrow is an spongy organ that is not a solid structure like most of the other organs. Rather, it is disseminated throughout the bones of the body, especially the skull, pelvis, vertebrae, rib and sternum. It forms and stores white blood cells, and then releases them into the bloodstream when they are mature. When a person has acute lymphocytic leukemia, their white blood cells quickly multiply in the bone marrow, which means that an overwhelming number of immature lymphocytes enter the bloodstream and lymph tubes and eventually replace the normal blood cells.

As this profusion of immature white blood cells overfills the blood stream and smalls tubes that contain the lymph, the result is that the lymph tissue becomes swollen. Because there is a lack of normal white blood cells that typically protect the body from bacterial or viral invasion, the affected person will be at greater risk of developing a separate infection. It is possible for the accumulation of white blood cells to overwhelm and destroy other types of blood cells in the body. Besides white blood cells, the bone marrow also generates red blood cells and platelets. The function of red blood cells is to convey oxygen and other essential materials to the tissue of the body. The function of the platelets is to facilitate blood clotting. As acute lymphocytic leukemia becomes worse, it is possible for these other types of blood cells to become reduced. When the body does not have enough red blood cells, it develops a condition called "anemia". When there is a deficiency of platelets in the body, a person will be more prone to bleeding or bruising. It will also take longer for wounds to clot and heal. In some extreme cases, the profusion of white blood cells affects the spinal cord or the brain, which can cause serious and permanent damage to the central nervous system.

Acute lymphocytic leukemia has often been thought of as a child's disease. It is responsible for almost 85 percent of all child-related cases of leukemia. However, it is found more often in adults than children. Most people who have developed this form of cancer are either under the age of ten or over the age of fifty. Every year, approximately 4000 new cases of acute lymphocytic leukemia are diagnosed in the United States.

The cause of acute lymphocytic leukemia is unknown. There are certain factors that can put a person more at risk of developing this condition. Prolonged exposure to radiation, and certain drugs and chemicals (like benzene) can predispose a person to being affected by acute lymphocytic leukemia. People who work in industries that involve painting, plastic and varnish manufacturing, glue, rubber, shoe-making, chemical manufacturing, medical equipment manufacturing and alcohol distilling are more at risk of developing the disease. There is also some evidence that certain viral infections are associated with the disease. People who have had exposure to the HTLV virus, or who have Down's syndrome or Klinefelter's syndrome are more likely to get acute lymphocytic leukemia than others.

Symptoms

The symptoms of this disease can be extremely vague or nonspecific. They can resemble the symptoms of the flu or other prevalent infections. In some instances, there are no symptoms at all. These symptoms can be caused by a lack of normal white blood cells, anemia, or a low platelet count. When there are symptoms, they include:

a long-lasting fever
weakness, fatigue, or tiredness
weight loss
repeated infections and immune system breakdowns
easy bruising and bleeding; particularly from the gums
blood in the stool or urine
paleness
swollen lymph nodes
pain in the bones and joints
enlargement of the spleen or liver

Even if there are no symptoms present, a doctor can usually detect acute lymphocytic leukemia during a physical examination. For this reason, it is a good idea that a person go in for regular health check-ups.

Diagnosis/Treatment

A doctor may suspect acute lymphocytic leukemia during a regular health examination. There are a few tests that a doctor can use in order to confirm a diagnosis.

One such test is a routine blood test. Leukemia cells can be easily viewed and identified underneath a microscope. Using this kind of lab test, a doctor can also make a count of the number of leukemia cells present in the blood, and thus assess the extent of the disease.

If the doctor feels it is necessary, they may also take a bone marrow sample. This is a simple procedure in which a sample of bone marrow is typically taken from the pelvic bone. The sample is extracted through a bone marrow needle, and the area is well anesthetized beforehand. Besides a specimen of the actual marrow, a doctor may also remove a small amount of liquid containing lymph and blood in order to scan the fluid for leukemia cells. This procedure is sometimes referred to as a "bone marrow biopsy".

In some instances, a doctor will make the diagnosis by performing a spinal tap. In this procedure, a needle is inserted into the spine in order to extract a small portion of spinal fluid. The doctor will then scan this fluid beneath a microscope to see if leukemia cells are present.

Although there is no guaranteed cure for acute lymphocytic leukemia, the symptoms can be treated so that the disease goes into remission. Sometimes, the disease goes into remission for the rest of the person's life. Besides helping the doctor diagnose the condition, the lab tests also allow the doctor to choose the appropriate forms of treatment for the affected person. One reason treatment is different in every case is that the severity of the disease changes from person to person. People are considered low risk if the chance of recurrence is low and the chance of effective treatment is high. If the opposite is the case, then the person is considered high risk.

Acute lymphocytic leukemia can either be untreated, in remission, or recurring. This disease is considered untreated if the person has never been diagnosed with the condition and there is a profusion of white blood cells in the lymph tubes. It is considered in remission if the disease has already been treated and the white blood cell count is normal. It is considered to be in a recurring stage if the condition has already been successfully treated, and the white blood cell count is once again escalating.

Because there is no guaranteed cure, treatment focuses on putting the disease into remission and reducing symptoms. The treatment process for acute lymphocytic leukemia can be difficult and long-lasting. It typically consists of either chemotherapy or radiation therapy.

There are two major stages of treatment. The first stage is called the "remission induction" stage. The intention of this stage is to put the disease in remission, which is the state in which the white blood cell count goes back to normal. The common form of treatment for this stage is chemotherapy, which involves the use of chemicals in order to eradicate the malignant cells. Although this form of therapy is extremely effective, it can have negative side effects. The most common side effect is nausea. In the past few years, other drugs have been developed to counter this effect. Chemotherapy is considered a systematic therapy because the chemicals travel the bloodstream and kill leukemia cells throughout the entire body. Sometimes, the doctor will inject the chemicals into the spinal fluid that circles around the brain and spine. This is referred to as "intrathecal chemotherapy". The chemicals can be taken either orally or intravenously. One thing that a person must consider is that when chemotherapy is given intravenously, it can damage the veins.

The remission induction phase typically lasts up to three months. It is estimated that nearly 85 percent of all leukemia cases go into remission after intensive chemotheraphy. However, in most cases, leukemia cells still remain in the body, and the disease will recur unless the person undergoes what is called "continuation therapy". The purpose of continuation therapy is to kill any remaining malignant cells in the body. It typically involves a short period of aggressive chemotherapy, followed by mild chemotherapy that is sustained for up to two years. In some instances, leukemia cells accumulate in the central nervous system. While a doctor may inject chemicals into the spinal fluid, this method of treatment is not always effective. As a result, a doctor will often resort to radiation therapy that can be focused on the brain and spinal cord in addition to the chemotherapy.

Radiation therapy involves focusing high-frequency energy on the body. Radiation is effective because it prevents leukemia cells from multiplying and growing. By performing this function, radiation can successfully put the disease into remission, and prevent the possibility of relapse. Radiation treatment can last up to five weeks, during which a patient is given low-level doses over several sessions. Although the actual treatment is painless, there can be side effects. A common side effect is nausea. It is an acute side effect, and will only last along as the treatment. Another concern is that exposure to radiation can predispose a person to developing cancer.

Even if leukemia is not present in the brain, a doctor may still use radiation therapy and chemotherapy on the brain and spinal cord in order to prevent the accumulation of white blood cells in this part of the body.

If a person has a high risk condition, does not experience a remission, or relapses immediately after remission, they may undergo a bone marrow transplant. In this procedure, high-level doses of chemotherapy are used to destroy the bone marrow in an affected person's body. After this occurs, doctors replace the destroyed bone marrow with bone marrow from a healthy person. In order for this to be successful, the bone marrow of both people must be almost identical. In most cases, the bone marrow donor is related to the leukemia-affected person. Another type of bone marrow transplant involves the doctor extracting bone marrow from the affected person. This bone marrow is treated so that all leukemia cells are eradicated, and then it is frozen. After this occurs, the person is given high level doses of chemotherapy in order to destroy all remaining bone marrow. The treated bone marrow is then thawed and replaced.

In recent years there have been great improvements in the treatment of acute lymphocytic leukemia. Almost 80 percent of all children who develop this condition are treated successfully so that the disease goes into permanent remission. The disease is not so curable in adults. Only 20 percent of all adults who have acute lymphocytic are able to fight it into permanent remission.