Acute lymphoblastic leukemia
Acute lymphoblastic leukemia (ALL) is a cancer of the lymphoid line of blood cells characterized by the development of large numbers of immature lymphocytes. Symptoms may include feeling tired, pale skin color, fever, easy bleeding or bruising, enlarged lymph nodes, or bone pain. As an acute leukemia, ALL progresses rapidly and is typically fatal within weeks or months if left untreated.
| Acute lymphoblastic leukemia | |
|---|---|
| Other names | Acute lymphocytic leukemia, acute lymphoid leukemia |
| Bone marrow aspirate smear from a person with precursor B-cell ALL. The large purple cells are lymphoblasts. | |
| Specialty | Hematology, oncology |
| Symptoms | Feeling tired, pale color, fever, easy bleeding or bruising, bone pain, enlarged lymph nodes |
| Complications | Infection, tumor lysis syndrome |
| Usual onset | 2–5 years old |
| Types | B-cell ALL, T-cell ALL |
| Causes | Usually unknown |
| Risk factors | Identical twin with ALL, Down syndrome, Fanconi anemia, ataxia telangiectasia, Klinefelter syndrome, high birth weight, significant radiation exposure |
| Diagnostic method | Blood tests and bone marrow examination |
| Differential diagnosis | Infectious mononucleosis, acute myeloid leukemia, lymphoblastic lymphoma, aplastic anemia |
| Treatment | Chemotherapy, stem cell transplantation, radiation therapy, targeted therapy |
| Prognosis | Children: 90% five-year survival rate Adults: 35% five-year survival |
| Frequency | 1 in 1,750 children |
| Deaths | 111,000 (2015) |
In most cases, the cause is unknown. Genetic risk factors may include Down syndrome, Li–Fraumeni syndrome, or neurofibromatosis type 1. Environmental risk factors may include significant radiation exposure or prior chemotherapy. Evidence regarding electromagnetic fields or pesticides is unclear. Some hypothesize that an abnormal immune response to a common infection may be a trigger. The underlying mechanism involves multiple genetic mutations that results in rapid cell division. The excessive immature lymphocytes in the bone marrow interfere with the production of new red blood cells, white blood cells, and platelets. Diagnosis is typically Acute lymphoblastic leukemia based on blood tests and bone marrow examination.
Acute lymphoblastic leukemia is typically treated initially with chemotherapy aimed at bringing about remission. This is then followed by further chemotherapy typically over a number of years. Treatment usually also includes intrathecal chemotherapy since systemic chemotherapy can have limited penetration into the central nervous system and the central nervous system is a common site for relapse of acute lymphoblastic leukemia.
Treatment can also include radiation therapy if spread to the brain has occurred. Stem cell transplantation may be used if the disease recurs following standard treatment. Additional treatments such as Chimeric antigen receptor T cell immunotherapy are being used and further studied.
Acute lymphoblastic leukemia affected about 876,000 people globally in 2015 and resulted in about 111,000 deaths. It occurs most commonly in children, particularly those between the ages of two and five. In the United States it is the most common cause of cancer and death from cancer among children. Acute lymphoblastic leukemia is notable for being the first disseminated cancer to be cured. Survival for children increased from under 10% in the 1960s to 90% in 2015. Survival rates remain lower for babies (50%) and adults (35%).