Definition of Leukemia/Lymphomas There are different types of leukemia and lymphoma.   Acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell). It is a cancer of the blood and bone marrow, and usually gets worse quickly if it is not treated. Normally, the bone marrow produces stem cells (immature cells) that develop into mature blood cells. There are three types of mature blood cells:

(1) Red blood cells that carry oxygen and other materials to all tissues of the body,

(2) White blood cells that fight infection and diseases, and

(3) Platelets that help prevent bleeding by causing blood clots to form.

 

In ALL, too many stem cells develop into a type of white blood cell called lymphocytes. These lymphocytes may also be called lymphoblasts or leukemic cells. The lymphocytes involved in ALL are not able to fight infection very well. Also, as the number of lymphocytes increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may cause infection, anemia, and easy bleeding. The cancer can also spread to the central nervous system (brain and spinal cord). It should also be noted that acute lymphoblastic leukemia is the most common type of cancer in children.

 

Acute myeloid leukemia (AML) is a type of cancer in which the bone marrow makes abnormal myeloblasts (a type of white blood cell), red blood cells, or platelets. AML is a cancer of the blood and bone marrow that usually gets worse quickly if it is not treated. It is the most common type of acute leukemia in adults. AML is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia, and acute nonlymphocytic leukemia. Normally, the bone marrow produces stem cells that develop into mature blood cells. In AML, the stem cells usually develop into a type of immature white blood cell called myeloblasts (or myeloid blasts). The myeloblasts in AML are abnormal and do not mature into healthy white blood cells. Sometimes in AML, too many stem cells develop into abnormal red blood cells or platelets. These abnormal white blood cells, red blood cells, or platelets are also called leukemia cells or blasts. Leukemia cells are unable to do their usual work and can build up in the bone marrow and blood so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur. The leukemia cells can spread outside the blood to other parts of the body, including the central nervous system, skin, and gums.

 

Non-Hodgkin's lymphoma is a disease in which malignant (cancer) cells form in the lymph system. The lymph system is part of the immune system. Because lymph tissue is found throughout the body, adult non-Hodgkin's lymphoma can begin in almost any part of the body. Cancer can spread to the liver and many other organs and tissues. Non-Hodgkin's lymphoma can occur in both adults and children. Treatment for children, however, is different than treatment for adults.

 

Hodgkin's lymphoma is a cancer of the immune system that is marked by the presence of a type of cell called the Reed Sternberg cell. Symptoms include the painless enlarged lymph nodes, spleen, or other immune tissue. Other symptoms include fever, weight loss, fatigue, or night sweats. Also called Hodgkin's disease.

 

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Causes

Previous chemotherapy and exposure to radiation may affect the risk of developing adult ALL. Possible risk factors include the following: being male, being white, being older than 70, past treatment with chemotherapy or radiation therapy, exposure to atomic bomb radiation, and having a certain genetic disorder such as Down Syndrome. For children, exposure to radiation and family history may affect the risk of developing childhood ALL. Possible risk factors include the following: having a brother or sister with leukemia, being white or Hispanic, living in the United States, being exposed to x-rays before birth, being exposed to radiation, past treatment with chemotherapy or other drugs that weaken the immune system, and having certain genetic disorders such as Down's Syndrome.

 

Smoking, previous chemotherapy treatment, and exposure to radiation may affect the risk of developing adult AML. Possible risk factors for AML include the following: being male, smoking, especially after age 60, having had treatment with chemotherapy or radiation therapy in the past, having had treatment for childhood acute lymphoblastic leukemia in the past, being exposed to atomic bomb radiation or the chemical benzene, and having a history of a blood disorder such as myelodysplastic syndrome. For children, AML risk factors include: having a brother or sister, especially a twin, with leukemia, being Hispanic, being exposed to cigarette smoke or alcohol before birth, having a history of myelodysplastic syndrome (also called preleukemia) or aplastic anemia, past treatment with chemotherapy or radiation therapy, being exposed to ionizing radiation or chemicals such as benzene, and having certain genetic disorders such as Down syndrome or Fanconi's anemia.

 

Age, gender, and a weakened immune system can affect the risk of developing non-Hodgkin's lymphoma. Risk factors include the following: being older, male, or white, having an inherited immune disorder, an autoimmune disease, HIV/AIDS, human T-lymphotrophic virus type I or Epstein-Barr virus, a history of Helicobacter pylori infection, taking immunosuppressant drugs after an organ transplant, being exposed to certain pesticides, a diet high in meats and fats, and past treatment for Hodgkin's lymphoma.

 

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Diagnosis

Tests that examine the blood and bone marrow are used to detect and diagnose various types of leukemia and lymphomas.

 

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
• Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
  • The number of red blood cells, white blood cells, and platelets.
    The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made up of red blood cells.
• Peripheral blood smear: A procedure in which a sample of blood is checked for the presence of blast cells, number and kinds of white blood cells, the number of platelets, and changes in the shape of blood cells.
• Bone marrow aspiration and biopsy: The removal of a small piece of bone and bone marrow by inserting a needle into the hipbone or breastbone. A pathologist views both the bone and bone marrow samples under a microscope to look for abnormal cells.
• Cytogenetic analysis: A test in which the cells in a sample of blood or bone marrow are looked at under a microscope to find out if there are certain changes in the chromosomes in the lymphocytes. For example, sometimes in ALL, part of one chromosome is moved to another chromosome. This is called the Philadelphia chromosome.
• Immunophenotyping: A test in which the cells in a sample of blood or bone marrow are looked at under a microscope to find out if malignant (cancerous) lymphocytes began from the B lymphocytes or the T lymphocytes.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it.
• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• Lymph node biopsy: The removal of all or part of a lymph node. A pathologist views the tissue under a microscope to look for cancer cells. One of the following types of biopsies may be done:
  • Excisional biopsy: The removal of an entire lymph node.
    Incisional biopsy: The removal of part of a lymph node.
  • Core biopsy: The removal of part of a lymph node using a wide needle.
    Needle biopsy: The removal of part of a lymph node using a thin needle. This procedure is also called a fine-needle aspiration biopsy.
• Liver function tests: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by the liver. For non-Hodgkin's lymphoma, the blood is checked for an enzyme called lactate dehydrogenase (LDH). LDH levels help determine prognosis (chance of recovery).
• Thoracentesis: The removal of fluid from the sac that surrounds the lung, using a needle inserted between the ribs. A pathologist views the fluid under a microscope to look for cancer cells.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

 

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Treatment

The treatment of adult ALL is done in phases:

Remission induction therapy: This is the first phase of treatment. Its purpose is to kill the leukemia cells in the blood and bone marrow. This puts the leukemia into remission.

Maintenance therapy: This is the second phase of treatment. It begins once the leukemia is in remission. The purpose of maintenance therapy is to kill any remaining leukemia cells that may not be active but could begin to regrow and cause a relapse. This phase is also called remission continuation therapy.

 

Treatment called central nervous system (CNS) sanctuary therapy is usually given during each phase of therapy. Because chemotherapy that is given by mouth or injected into a vein may not reach leukemia cells in the CNS (brain and spinal cord), the cells are able to find “sanctuary” (hide) in the CNS. Intrathecal chemotherapy and radiation therapy are able to reach leukemia cells in the CNS and are given to kill the leukemia cells and prevent the cancer from recurring (coming back). CNS sanctuary therapy is also called CNS prophylaxis.

 

Children with ALL should have their treatment planned by a team of doctors with expertise in treating childhood leukemia.

 

The child's treatment will be managed by a pediatric oncologist, a doctor who specializes in treating children with cancer. The pediatric oncologist may refer you to other pediatric doctors who have experience and expertise in treating children with leukemia and who specialize in certain areas of medicine. These may include the following specialists:

• Hematologist.
• Medical oncologist.
• Pediatric surgeon.
• Radiation oncologist.
• Endocrinologist.
• Neurologist.
• Neuropathologist.
• Neuroradiologist.
• Pediatric nurse specialist.
• Social worker.
• Rehabilitation specialist.
• Psychologist.

 

Regular follow-up exams are very important. Side effects can result from treatment long after it ends. Radiation therapy to the head may affect the child's developing brain and may cause second cancers, especially brain tumors. Early diagnosis and treatment of these secondary brain tumors may help lower the risk from these brain tumors.

 

The treatment of childhood ALL usually has 3 phases:

 

Induction therapy: This is the first phase of treatment. Its purpose is to kill the leukemia cells in the blood and bone marrow. This puts the leukemia into remission.

 

Consolidation/intensification therapy: This is the second phase of therapy. It begins once the leukemia is in remission. The purpose of consolidation/intensification therapy is to kill any remaining leukemia cells that may not be active but could begin to regrow and cause a relapse.

Maintenance therapy: This is the third phase of treatment. Its purpose is to kill any remaining leukemia cells that may regrow and cause a relapse. Often the cancer treatments are given in lower doses than those used for induction and consolidation/intensification therapy.

 

Treatment called central nervous system (CNS) sanctuary therapy is usually given during each phase of therapy. Because chemotherapy that is given by mouth or injected into a vein may not reach leukemia cells in the CNS (brain and spinal cord), the cells are able to find “sanctuary” (hide) in the CNS. Intrathecal chemotherapy and radiation therapy are able to reach leukemia cells in the CNS and are given to kill the leukemia cells and prevent the cancer from recurring (coming back). CNS sanctuary therapy is also called CNS prophylaxis.

 

Types of standard treatment used in leukemia and lymphoma:

 

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the spinal column, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). Combination chemotherapy is treatment using more than one anticancer drug. The way the chemotherapy is given depends on the type and stage of the cancer being treated.

 

Intrathecal chemotherapy may be used to treat adult ALL that has spread, or may spread, to the brain and spinal cord. When used to prevent cancer from spreading to the brain and spinal cord, it is called central nervous system (CNS) sanctuary therapy or CNS prophylaxis. Intrathecal chemotherapy is given in addition to chemotherapy by mouth or vein.

 

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. External radiation therapy may be used to treat adult ALL that has spread, or may spread, to the brain and spinal cord. When used this way, it is called central nervous system (CNS) sanctuary therapy or CNS prophylaxis.

 

Chemotherapy with stem cell transplant

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.

 

Other drug therapy

Arsenic trioxide and all-trans retinoic acid (ATRA) are anticancer drugs that kill leukemia cells, stop the leukemia cells from dividing, or help the leukemia cells mature into white blood cells. These drugs are used in the treatment of a subtype of AML called acute promyelocytic leukemia.

Other types of treatment are being tested in clinical trials. These include the following:

 

Biologic therapy

Biologic therapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.

 

This summary section refers to specific treatments under study in clinical trials, but it may not mention every new treatment being studied. Information about ongoing clinical trials is available from the NCI website.

 

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Prognosis (Outlook)

Certain factors affect prognosis (chance of recovery) and treatment options for adult ALL. These include the age of the patient, whether the cancer has spread to the brain or spinal cord, whether the Philadelphia chromosome is present, and whether the cancer has been treated before or has recurred. 60% to 80% of adults with acute lymphoblastic leukemia can be expected to attain complete remission status following appropriate induction therapy. Approximately 35% to 40% of adults with ALL can be expected to survive 2 years with aggressive induction combination chemotherapy and effective supportive care during induction therapy. A few studies that use intensive multiagent approaches suggest that a 50% 3-year survival rate is achievable in selected patients, but these results must be verified by other investigators.

 

For childhood ALL, the prognosis depends on age and white blood cell count at diagnosis, how quickly and how low the white blood cell count drops after initial treatment, gender and race, whether the leukemia cells began from the B lymphocytes or the T lymphocytes, whether there are certain changes in the chromosomes of lymphocytes, and whether the leukemia has spread to the brain and spinal cord. Among children with ALL, more than 95% attain remission and 75% to 85% survive free of leukemia recurrence at least 5 years from diagnosis with current treatments that incorporate systemic therapy and specific central nervous system preventive therapy.

 

The prognosis for adult acute myeloid leukemia depends on the age of the patient, the subtype of AML, whether the patient received chemotherapy in the past to treat a different cancer, whether there is a history of a blood disorder such as myelodysplastic syndrome, whether the cancer has spread to the central nervous system, and whether the cancer has been treated before or recurred. Advances in the treatment of AML have resulted in substantially improved complete remission rates. Treatment should be sufficiently aggressive to achieve remission because partial remission offers no substantial survival benefit. Approximately 60% to 70% of adults with AML can be expected to attain complete remission status following appropriate induction therapy. More than 15% of adults with AML (about 25% of those who attain complete remission) can be expected to survive 3 or more years and may be cured. Remission rates are inversely related to age, with an expected remission rate of <65% for those younger than 60 years.

 

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Research

The National Cancer Institute has identified ten areas of research that could revolutionize the prevention, diagnosis, treatment and care of individuals with hematological cancers (leukemia, lymphoma, and myeloma). The priority research areas are summarized below.

• In etiology, understand the interaction among genotype, immune function, infectious agents, environmental toxins, and lifestyle factors that can lead to hematopoietic malignancy.
• In pathobiology, identify the basic mechanisms responsible for genome instability, chromosome translocations, and other mutations in hematological malignancies. Reducing the incidence of hematological cancers will require a better understanding of: (1) how various types of DNA damage occur in hematopoietic cells, (2) the impact of various genetic factors on susceptibility to DNA damage, (3) repair capacity and other types of cellular responses to DNA damage, and (4) the role of environment in the broadest sense.
• Also in pathobiology, define the relationship between the development of hematological malignancies and the host biological environment.
• Also in pathobiology, provide molecular characterization of hematological malignancies, including the characterization of global patterns of genetic and epigenetic alterations and RNA and protein expression, as well as the validation of the molecular targets necessary for the survival, proliferation, and evolution of hematological malignancies.
• Also in pathobiology, further develop research on stem cells, both multilineage and single lineage.
• In drug development and therapeutics, develop the required resources to translate lead structures and molecules into effective therapeutic agents. Hasten the translation of candidate validated targets to lead compounds and subsequent clinical trials and support the development of orphan therapeutic agents and diagnostics, including FDA approval.
• Also in drug development and therapeutics, foster partnerships between NCI and academia, advocates, cooperative groups, industry, and FDA to expedite drug development and availability of therapies.
• In education, communication, and survivorship research, determine how to provide accurate, timely, and tailored information to patients to improve medical decision-making, access to clinical trials, quality of care during active trement and follow-up, and quality of life.
• Also in education, communication, and survivorship research, develop education and training programs for certification of physicians and centers for diagnosis, treatment, and clinical trials in hematological malignancies.
• Also in education, communication, and survivorship research, identify and target individuals and populations at high risk for adverse long-term outcomes to define the biological basis of identified associations and facilitate the design and testing of intervention and prevention strategies.

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