ACUTE LYMPHOBLASTIC LEUKEMIA OVERVIEW
Acute lymphoblastic leukemia (ALL) is a cancer of blood cells. ALL is also known as lymphoblastic lymphoma when the disease primarily involves lymph nodes rather than the blood and bone marrow. ALL involves a type of white blood cell called a lymphocyte. Acute means that it develops and advances quickly, and requires immediate treatment.
Normally, lymphocytes and other blood cells are produced by the bone marrow (the spongy area in the middle of bones) in a controlled fashion. In someone with ALL, this process is abnormal. Large numbers of immature and abnormal lymphocytes (lymphoblasts) are produced and released into the blood stream. In their immature state, these cells cannot perform their usual functions, leaving the person vulnerable to anemia, infection, and bleeding.
The overproduction of lymphoblasts prevents the bone marrow from producing other important blood cells, including red blood cells, other types of white blood cells (especially neutrophils, sometimes called "polys"), and platelets. The lymphoblasts can collect in certain areas of the body, such as the brain, spinal cord, and lymph nodes (glands).
GENERAL INFORMATION ABOUT ALL TREATMENT
A number of medications, or chemotherapy agents, are known to be effective against ALL. However, the best combination of medicines or the best treatment schedule is still not known. Because there are so many different medicines, dosing schedules, and combinations, it has been difficult to study any one component of treatment thoroughly.
However, general principles of treatment have emerged and are followed in most cancer treatment centers. The exact regimens may vary from one center to another. Regimens can also vary based upon individual characteristics such as your age, the total number of white blood cells, or characteristics of the genetic changes. (See "Cytogenetics in acute lymphoblastic leukemia".)
Treatment side effects — Side effects of treatment will depend on the actual medicines being used, the schedule of treatment, and other factors. Many of the chemotherapy medicines used to treat ALL share common side effects such as hair loss (which is temporary), nausea and vomiting, mouth sores, diarrhea or constipation, and an increased risk of infections and bleeding. Treatment to minimize these side effects is available.
Phases of treatment — The usual treatment for ALL can be divided into three phases: induction of remission, consolidation/intensification of therapy, and remission maintenance (also called continuation therapy). A summary of one regimen’s entire treatment process is available in the table (table 1).
Treatment of high-risk disease — Patients with high risk disease, including those with Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia and Burkitt leukemia/lymphoma, require special treatment programs that use different medications and doses from those used in patients with standard risk ALL. In addition, allogeneic stem cell transplantation is more frequently recommended in those patients with Ph+ ALL.
INDUCTION OF REMISSION
Induction of remission takes about four weeks and is almost always performed while the patient remains in the hospital. Treatment includes: vincristine (Oncovin) and an anthracycline (such as daunorubicin or doxorubicin) along with prednisone, dexamethasone, or another steroid hormone (table 1). Patients with Philadelphia chromosome positive ALL require the addition of a BCR-ABL tyrosine kinase inhibitor, such as imatinib or dasatinib. (See "Induction therapy for Philadelphia chromosome negative acute lymphoblastic leukemia in adults".)
Vincristine and the anthracycline drugs are anti-cancer chemotherapy drugs. These drugs work by interfering with the ability of rapidly growing cells (such as cancer cells) to divide or reproduce themselves. Because most of an adult's normal cells are not actively growing, they are less affected by chemotherapy, with the exception of bone marrow (where the blood cells are produced), the hair, and the cells lining the gastrointestinal tract.
Effects of chemotherapy on these and other normal tissues cause side effects during treatment, including anemia (lowered red blood cell count), an increased risk of infection (lowered white blood cell count), and bleeding (lowered platelet count).
Vincristine and the anthracycline drugs are given through an intravenous (IV) line. Prednisone or dexamethasone can be given either by mouth or IV. Other medicines such as cyclophosphamide (Cytoxan, given IV) or L-asparaginase (Elspar, given as a subcutaneous, intramuscular or IV injection) may also be given.
Approximately 80 percent of newly diagnosed adults with ALL enter complete remission after the initial treatment, meaning that there are no detectable lymphoblasts in the blood or bone marrow and that the bone marrow is functioning normally. However, such remissions are usually short-lived unless additional chemotherapy is given (see 'Consolidation/intensification therapy' below).
Once remission is achieved, additional therapy is needed to avoid relapse. Relapse probably occurs because abnormal cells are still present, even though these cells cannot be detected by routine examination of the blood or bone marrow. (See "Post-remission therapy for Philadelphia chromosome negative acute lymphoblastic leukemia in adults".)
Chemotherapy — Some of the same medicines given during induction are also used during remission consolidation therapy, which may last for several months. Most of this treatment can take place during the day, without the need to remain in the hospital overnight (table 1).
In addition to scheduled doses of chemotherapy, many treatment programs call for preventive treatment of the central nervous system (the brain and spinal cord). Abnormal lymphoblasts in the brain often do not respond to chemotherapy given only into a vein, but must be treated directly with radiation to the head and/or injection of chemotherapy, such as methotrexate, into the fluid surrounding the spinal cord and brain through a lumbar puncture (also called a spinal tap).
Stem cell transplantation — Stem cell transplantation, also called bone marrow transplantation or hematopoietic stem cell transplantation, is a treatment in which the patient is given very high doses of chemotherapy or total body irradiation (TBI), called myeloablative treatment. This kills cancer cells but also destroys all normal cells developing in the bone marrow. This means that the body's normal source of blood cells (the bone marrow) is no longer functional. (See "General principles of hematopoietic cell transplantation for acute lymphoblastic leukemia in adults".)
After the treatment, the patient requires a supply of healthy young blood cells (called stem cells) to be reintroduced, or transplanted. This is done by a transfusion of blood stem cells from a healthy well-matched donor. The transplanted cells re-establish the blood cell production process in the bone marrow. (See "Patient information: Bone marrow transplantation (stem cell transplantation) (Beyond the Basics)".)
Current data indicate that there is no clear advantage to stem cell transplantation as compared with chemotherapy during consolidation therapy for standard risk patients in their first complete remission, although it may shorten the overall treatment course. However, allogeneic stem cell transplantation is recommended, if necessary, following a relapse when patients are in a second complete remission, and for subsets of patients with more aggressive forms of ALL in first remission.
- Allogeneic transplantation uses stem cells from a donor other than the patient, ideally a sibling with a similar genetic makeup (called a matched related donor, or MRD). If the patient does not have a sibling with similar genetic characteristics, an unrelated person with a similar genetic makeup may be used (called a matched unrelated donor, or MUD). Another possibility is to use a sibling with partially similar genetic characteristics, although this is not as well studied (sometimes called a partially matched family member donor). Umbilical cord blood can also provide a source of unrelated stem cells.
Allogeneic transplantation treats ALL in two ways. First, high doses of chemotherapy or total body irradiation are given immediately before the transplant, which aggressively attacks and kills the leukemia cells present in the blood and bone marrow. Second, when cells from another person are transfused, some of the donor stem cells mature into immune cells, and these donor immune cells can cause an immune response that helps destroy any remaining leukemia cells. This is called the "graft versus leukemia" or "graft versus tumor" effect. Unfortunately, this response is closely associated with a complication called "graft versus host disease" in which the immune response includes an attack on some of the patient's own healthy organs. Symptoms can include severe skin rash, diarrhea, liver damage, and other problems. Still, allogeneic transplantation is preferred over autologous transplantation in patients with ALL.
- Autologous transplantation, which uses the patient's own stem cells collected while the patient is in complete remission, is of no greater benefit than chemotherapy for adults with ALL. Thus, it is generally not recommended.
Remission maintenance therapy or remission continuation therapy is a standard part of ALL treatment, although research studies have not clearly shown its benefit for adults. It is also unclear how long therapy should continue. Depending upon the program chosen, treatment is often continued for three years (table 1).
During maintenance treatment, oral medications (pills) are taken on certain days of the month and intravenous (IV) chemotherapy may be given into a vein once per month. Side effects during this phase of treatment are less frequent and less severe than those experienced during earlier stages of treatment. Most people are able to return to full activity during their maintenance treatment period.
RESIDUAL DISEASE AND RELAPSE RISK
Following the standard two to three years of treatment, patients in complete clinical remission should have a bone marrow aspiration and biopsy repeated every three to six months for at least the next two years. This allows for early detection and treatment if relapse were to occur. Patients with ALL who maintain complete, continuous remission for four to five years are considered cured and no longer need routine bone marrow examination. However, relapses of ALL as long as 21 years after diagnosis have been reported.
Unfortunately, up to 25 percent of adults with ALL have disease that is resistant to the initial induction of remission. In addition, many adults with ALL who do attain an initial complete remission will ultimately suffer a relapse. Although a second remission can often be achieved, re-treatment of such patients is generally unsuccessful in the long run, and most will die of their disease or of complications of treatment. Allogeneic transplantation is generally recommended for patients who attain a second remission.
Treatment of relapse or resistant disease — A second remission may be attained using a similar induction regimen if the relapse occurs more than two years following initial treatment. However, this approach is not recommended if a patient has primary resistant disease (complete remission was never attained) or for those who relapse while receiving induction or maintenance therapy. (See "Treatment of relapsed or refractory acute lymphoblastic leukemia in adults".)
Salvage regimens are also called rescue treatments and are used after standard frontline treatments have failed. These regimens are designed to reduce symptoms and prolong survival, but may not be able to cure the disease. Optimally, patients should enroll onto a clinical trial specifically designed for treatment of resistant or relapsed ALL so they can get access to new agents given either alone or in combination.
Allogeneic stem cell transplantation is also a reasonable option for selected patients with resistant or relapsed disease. All eligible patients who achieve a second complete remission should consider allogeneic stem cell transplantation.
Many patients with leukemia will be asked to enroll on a clinical research trial. A clinical trial is a controlled way to study the effectiveness of new treatments or new combinations of known therapies. They are carefully designed and reviewed by experts in the field to provide state-of-the-art care for individual patients as well as to improve the outcomes of patients overall. Additional information concerning clinical trials for ALL can be obtained from the treatment team or the following websites:
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Acute lymphoblastic leukemia (ALL) (The Basics)
Patient information: Leukemia in adults (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Bone marrow transplantation (stem cell transplantation) (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Clinical manifestations, pathologic features, and diagnosis of precursor B cell acute lymphoblastic leukemia/lymphoma
Clinical manifestations, pathologic features, and diagnosis of precursor T cell acute lymphoblastic leukemia/lymphoma
Cytogenetics in acute lymphoblastic leukemia
General principles of hematopoietic cell transplantation for acute lymphoblastic leukemia in adults
Treatment of relapsed or refractory acute lymphoblastic leukemia in adults
Induction therapy for Philadelphia chromosome negative acute lymphoblastic leukemia in adults
Post-remission therapy for Philadelphia chromosome negative acute lymphoblastic leukemia in adults
Induction therapy for Philadelphia chromosome positive acute lymphoblastic leukemia in adults
Post-remission therapy for Philadelphia chromosome positive acute lymphoblastic leukemia in adults
The following organizations also provide reliable health information.