SPECIFIC LEUKEMIAS
Acute Lymphocytic Leukemia.

The following brief descriptions of the four major types of leukemia are intended to augment the preceding general information, which should be read first and which holds remarkably true when applied to each type.

Acute Lymphocytic Leukemia

Acute lymphocytic leukemia is the most common childhood cancer and the leukemia in which oncologists have achieved their highest rates of remission and cure. The incidence of the disease peaks between the ages of two and nine years, then declines rapidly. A second peak occurs in very old age. Males are affected more frequently than females.

The first symptoms experienced by most patients with acute lymphocytic leukemia are anemia, fever, fatigue, and minor enlargement of the lymph nodes. Laboratory examination shows abnormal cells in the blood and in the bone marrow, as well as elevated levels of uric acid in the blood caused by the increased metabolic activity of the cancer cells. Before effective chemotherapy was available, the average survival was about five or six months, with all patients succumbing within two to three years. Steady advances in therapy from single-drug treatment (in the 1950s) to multidrug treatment (in the 1960s) to prophylactic central nervous system radiation (in the 1970s) all abetted by enormous improvements in supportive care have radically altered this picture, especially for children.

 Bone marrow transplantation has its highest success rate in patients with this leukemia.
More than 95 percent of all children with this malignancy will enter complete remission. One half of them will stay in remission on maintenance therapy for two and a half to three years, after which therapy is discontinued. Of these, about 10 percent will relapse and be candidates for a second attempt at induction of remission, although with a lower chance of success than the first time. Altogether more than half of children with acute lymphocytic leukemia are being cured of their malignancy by currently available methods.

Adults now achieve a 70 percent complete remission rate on approximately the same treatment regimen used in children. The addition of other agents to the usual combination of vincristine, methotrexate, and prednisone appears to induce a complete remission in up to 90 percent of patients. The duration of remission is shorter in adults than in children and the apparent cure rate is about 35 percent. In both adult and childhood disease, patients who stay in remission for over four years rarely relapse, and therapy can be discontinued.

Monoclonal antibodies and genetic studies have enabled researchers to
 
Sub divide the category of acute lymphocytic leukemia into several subclasses. These sophisticated techniques are largely of research interest, but they do offer some prognostic information. The early (but not definite) conclusion of this research is that acute lymphocytic leukemia is not a single disease entity, but rather several closely related pathological entities that appear much alike but are different in important ways. In the future, the subcategories may enable physicians to design more specific, more effective treatment schedules.