INTRODUCTION — Acute lymphoblastic leukemia (ALL), also known as lymphoblastic lymphoma when the disease primarily involves lymph nodes rather than the blood and bone marrow, is a cancer of blood cells. It involves a type of white blood cell called a lymphocyte. Acute means that it develops and advances quickly, requiring 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 production process is abnormal. Large numbers of immature and abnormal lymphocytes (lymphoblasts) are produced and released into the blood stream. In their immature state, they 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 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. Still, general principles of treatment have emerged and are followed in most cancer treatment centers, although the exact regimens given may vary from one center to another. Regimens can also vary based on characteristics such as the age of the patient, the total number of white blood cells, or characteristics of the acquired genetic changes in the leukemia cells, found in some patients with ALL.
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 loss of hair (which is temporary), nausea and vomiting, mouth sores, and an increased risk of infections and bleeding. Treatment to minimize these side effects is generally recommended. For example, anti-nausea medicines can be very effective in preventing nausea and vomiting, and mouth care can reduce the discomfort associated with sores in the mouth.
The usual treatment for ALL can be divided into three phases: induction of remission, consolidation/intensification of therapy, and maintenance. A summary of the entire treatment process is available in table 1 (show table 1). Patients with high risk disease (examples include those with Philadelphia chromosome positive (Ph+) ALL and Burkitts leukemia) require special treatment programs that use medications and doses different from those used in patients with standard risk ALL. In addition, allogeneic stem cell transplantation is more frequently recommended in these patients.
INDUCTION OF REMISSION — This phase of treatment 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 (show table 1).
Vincristine and the anthracycline drugs are anti-cancer chemotherapy drugs. These drugs work by interfering with the ability of rapidly growing cells (like 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 lining of the gastrointestinal tract. Effects of chemotherapy on these and other normal tissues cause side effects during treatment, including anemia (lowered red blood cell count), susceptibility to infection (lowered white blood cell count) and bleeding (lowered platelet count).
Vincristine and the anthracycline drugs are given through an intravenous (IV) line. Prednisone 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. In one study of 204 patients treated with cyclophosphamide, vincristine, doxorubicin and dexamethasone alternating with high-dose methotrexate and cytarabine (abbreviated as Hyper-CVAD), complete remission was obtained in 91 percent, with 42 percent of patients still in remission after an average of 40 months.
Approximately 80 percent of newly diagnosed adults with ALL enter complete remission, 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. Additional phases of treatment are described in the following sections.
CONSOLIDATION/INTENSIFICATION THERAPY — Once remission is achieved, additional therapy is needed to avoid relapse. Relapse is thought to occur because minimal residual disease is still present, even though it cannot be detected by routine examination of the blood or bone marrow.
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 without staying overnight in the hospital (show 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 cell transplantation, is a treatment in which the patient is given very high doses of chemotherapy or total body radiation, 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 critical blood components (the bone marrow) is no longer functional.
Attempts have been made to reduce the dose of chemotherapy or radiation for some patients, especially those who are older. This is called a non-myeloablative transplantation regimen. The hope with this regimen is that it would reduce early transplant related illness and death. However, the value of this regimen, as compared to its risks and expense, remains to be determined.
After the treatment, the patient requires a supply of healthy young blood cells (called stem cells) to be reintroduced, or transplanted. The transplanted cells reestablish the blood cell production process in the bone marrow. (See "Patient information: Overview of bone marrow transplantation").
The current data indicate that there is no clear advantage to stem cell transplantation as compared to chemotherapy during consolidation therapy for standard risk patients during the first complete remission, although it may shorten the overall treatment course. However, allogeneic stem cell transplantation is recommended following a second complete remission, if necessary, 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 radiation 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 injected, the donor stem cells undergo 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 organs. Symptoms can include severe skin rash, diarrhea, liver damage, and other problems. Still, allogeneic transplant 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 not recommended.
MAINTENANCE THERAPY — 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 two to two and one-half years (show 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 are 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, retreatment of such patients is generally unsuccessful in the long run, and most will die of their disease or of complications of treatment. In patients with ALL who received hematopoietic cell transplantation and were in complete remission at two years, the overall chance of being alive in complete remission at nine years was 82 percent [1]. The latest relapses in this group occurred at four to seven years.
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.
Salvage regimens are treatments used after all other available treatments have failed. They are intended to reduce symptoms and prolong survival, but may not be able to cure the disease. Optimally, such patients should enroll onto a clinical trial specifically designed for treatment of resistant ALL with new agents alone or in combination. Allogeneic stem cell transplantation is also a reasonable option for selected patients with resistant or relapsed disease.
THE ROLE OF CLINICAL TRIALS — Many patients with leukemia will be asked to enroll in 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: www.cancer.gov/clinical_trials http://clinicaltrials.gov
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Cancer Institute
(www.cancer.gov/cancer_information/)
American Cancer Society
(www.cancer.org)
The Leukemia & Lymphoma Society
(www.leukemia-lymphoma.org)
National Marrow Donor Program
(www.marrow.org)
People Living With Cancer: The official patient information
website of the American Society of Clinical Oncology
(www.plwc.org/portal/site/PLWC)
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Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Frassoni, F, Labopin, M, Gluckman, E, et al. Are patients with acute leukaemia, alive and well 2 years post bone marrow transplantation cured? A European survey. Acute Leukaemia Working Party of the European Group for Bone Marrow Transplantation (EBMT). Leukemia 1994; 8:924.
2. Brincker, H, Christensen, BE. Long-term survival and late relapses in acute leukaemia in adults. Br J Haematol 1990; 74:156.
3. Laport, GF, Larson, RA. Treatment of adult acute lymphoblastic leukemia. Semin Oncol 1997; 24:70.
4. Hoelzer, D. Gokbuget, N New approaches to acute lymphoblastic leukemia in adults: Where do we go? Semin Oncol 2000; 27:540.
5. Weisdorf, DJ, Woods, WG, Nesbit, ME Jr, et al. Allogeneic bone marrow transplantation for acute lymphoblastic leukaemia: Risk factors and clinical outcomes. Br J Haematol 1994; 86:62.
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