Credit: National Marrow Donor Program, The National Cancer Institute, The American Cancer Society

Janet has been diagnosed with acute lymphoblastic leukemia (ALL).

Acute lymphoblastic leukemia (ALL) is a fast-growing cancer of the white blood cells. Lymphocytes are a type of white blood cell that the body uses to fight infections. In ALL, the bone marrow makes lots of unformed cells called blasts that normally would develop into lymphocytes. However, the blasts are abnormal. They do not develop and cannot fight infections. The number of abnormal cells (or leukemia cells) grows quickly. They crowd out the normal red blood cells, white blood cells and platelets the body needs.

There are about 4,000 new cases of ALL in the United States each year. It appears most often in children younger than age 10. ALL is the most common leukemia in children. However, it can appear in people of any age — about one-third of cases are adults.
The American Cancer Society's most recent estimates for acute lymphocytic leukemia cancers in the United States are for 2009:

• 44,790 new cases of all types of leukemia.
• 5,760 new cases acute lymphocytic leukemia (ALL). About 1 out of 3 will be in adults.
• 1, 400 deaths from ALL. About 3 out of 4 will be in adults.
• The average person's lifetime risk of getting ALL is about 1 in 1,000.

Signs and symptoms
The symptoms a person with ALL has depend on how many normal blood cells he or she has. Symptoms also depend on how many leukemia cells there are and where they collect in the body.

• Red blood cells carry oxygen throughout the body. Low numbers of red blood cells can lead to anemia -- feeling tired or weak, being short of breath and looking pale.
• White blood cells fight infections. Low numbers of white blood cells can lead to fever and frequent infections that are hard to treat.
• Platelets control bleeding. Low numbers of platelets can lead to cuts that heal slowly, easy bruising or bleeding and tiny red spots under the skin (petechiae).
• High numbers of leukemia cells can cause pain in the bones or joints, lack of appetite, headache or vomiting. These symptoms are less common.

Treatment options for acute lymphoblastic leukemia
ALL can get worse quickly, so doctors usually begin treatment right away. To plan the treatment, doctors look at a patient's risk factors (also called prognostic factors). Risk factors are patient and disease traits that clinical research studies have linked to better or poorer outcomes from treatment. Examples of risk factors are a patient's age and the type of ALL he or she has.

For a patient with ALL, the treatment plan may include:

• Chemotherapy — drugs that destroy cancer cells or stop them from growing. Some form of chemotherapy will be part of the treatment plan for all patients with ALL.
• Radiation therapy — most patients do not receive radiation therapy. However, children who have signs of disease in the central nervous system (brain and spinal cord) or have a high risk of the disease spreading to this area may receive radiation therapy to the brain.
• Bone marrow or cord blood transplant (also called a BMT) — a transplant offers some patients the best chance for a long-term remission of their disease. Because transplants can have serious risks, this treatment is used for patients who are less likely to reach a long-term remission with chemotherapy alone.

Treatment of ALL

For ALL, chemo treatments are given in the phases described below. The total treatment usually takes about 2 years, with the maintenance phase taking up most of this time. Treatment may be more or less intense, depending on the subtype of ALL and other prognostic factors.

Remission induction: The purpose of the first phase is to bring about a remission. A remission means there are no signs and symptoms of the cancer. More than one chemo drug will be used and high doses will be given. Treatment to keep the leukemia cells from spreading to the central nervous system is often started at this time (see below).

Consolidation: If the patient goes into remission, the next phase is often a fairly short course of chemo using many of the same drugs and high doses that were used before. This treatment phase lasts for a few months. Central nervous system treatment may be continued at this time. Doctors may suggest a stem cell transplant for patients who are at a high risk of relapse.

Maintenance: Once the number of leukemia cells has been reduced by the first 2 phases of treatment, this last phase can begin. Maintenance, which usually means lower doses of chemo drugs, lasts about 2 years. Central nervous system treatment may also be continued.

Central nervous system treatment: Because ALL often spreads to the brain and spinal cord, patients often get chemo put right into the spinal fluid or radiation therapy of the head to prevent this kind of spread.

Response rates to treatment

As a rule, about 80% to 90% of adult patients will have a complete response to these treatments. That means that leukemia can no longer be seen in their bone marrow (remission). But in about half of these patients the leukemia will come back (relapse), so the overall cure rate is around 30% to 40%.

What if the leukemia doesn't respond or comes back after treatment?

If the leukemia doesn't go away with the first treatment then newer or stronger doses of drugs may be tried, although they are less likely to work. A stem cell transplant may be tried if the leukemia can be put into at least partial remission. Clinical trials of new treatment approaches may also be an option.

If the leukemia comes back (recurs) after treatment, it will most often do so in the bone marrow and blood. Once in a while, the brain or spinal fluid will be the first place it returns. In these cases, more chemo might put the disease into remission, although this it is not likely to last. If a second remission can be achieved, most doctors will advise some type of stem cell transplant if possible.

Stem cell transplant is a method of giving chemotherapy and replacing blood-forming cells destroyed by the cancer treatment. Stem cells (immature blood cells) are removed from the blood or bone marrow of the patient or a donor and are frozen and stored. After the chemotherapy is completed, the stored stem cells are thawed and given back to the patient through an infusion. These reinfused stem cells grow into (and restore) the body's blood cells.