What Is Leukemia?

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Which body systems are affected?

There are two body systems that leukemia affects. The immune system and the nervous system. The main role of the immune system is to protect the body against illness and infection caused by bacteria, viruses, fungi or parasites. The immune system is specifically important to cancer patients because of the following reasons: Cancer can weaken the immune system, cancer treatments may weaken the immune system, and the immune system may help to fight cancer. Cancer can weaken the immune system by spreading into the bone marrow. The cancer in the bone marrow stops the bone marrow making so many blood cells. Chemotherapy, biological therapies and radiotherapy can temporarily weaken immunity by causing a drop in the number of white blood cells made in the bone marrow. The immune system can help to fight cancer.

The main function of the nervous system is to control the human body. It consists of neuron tissues that form the nervous system. The central nervous system consists of majority of nervous system including the brain, spinal cord, neurons and transmitters that play an essential part in regular body functions. Since leukemia is a type of caner in the blood it can easily spread to the brain which is one of the most important parts in the nervous system, It is normal for the patient to experience seizures, problems with balance, problems with vision and headaches once the leukemia reaches the brain. The doctors can usually tell if the leukemia has spread to the central nervous system by taking a sample of fluid from the lower part of the back. In order to prevent leukemia from reaching the central nervous system a type of chemotherapy called intrathecal chemotherapy is required.

Treatments and Medications

The general treatment options for leukemia are chemotherapy, radiation therapy, targeted therapy, and supportive therapy however there are specific treatments based off of the type of leukemia.

The main treatment for acute lymphocytic leukemia is chemotherapy. This treatment is divided in four phases called remission induction, central nervous system directed therapy, consolidation and maintenance. Remission induction treatment is meant to kill leukemic cells in the blood and the bone marrow in order to put the disease into remission. Central nervous system directed therapy kills cancer cells in the central nervous system and prevents the disease from spreading to the spinal fluid. The consolidation phase is given after the disease is considered to be in remission. It is meant to kill the remaining leukemic cells that could begin growing again and cause the leukemia to recur. The maintenance phase is the final phase of chemotherapy treatment, it is used to kill any remaining cells that could cause a recurrence. People who have leukemia cells with the philadelphia chromosome are often given a targeted therapy drug called a tyrosine kinase inhibitor as part of their chemotherapy treatment however those who do not have philadelphia chromosomes do not need this drug with their treatment. Another treatment option is radiation therapy, it is used to prevent and treat the spread of acute lymphocytic leukemia to the central nervous system in preparation for a stem cell transplant and to relieve pain where the leukemia has spread to the bones. Radiation therapy can also sometimes be used to shrink a tumor that is pressing on the trachea or other vital organs. Another treatment option is a stem cell transplant that can be used during remission or following relapse if a complete or partial remission can be reached. Supportive therapy is also another treatment used to treat the complications that usually happen with treatments and the disease itself. Medications such as antibiotics, antivirals or antifungals that prevent and fight infections, blood transfusions to replace blood cells when counts are low, growth factors that regulate the growth, division and survival of cells, such as filgrastim to stimulate the body to make white blood cells, drugs to bring down high levels of some chemicals in the blood that increase when many cancer cells die at the beginning of treatment. Leukapheresis is a laboratory procedure in which white blood cells are separated from a sample of blood then the remaining blood is returned to the body. These can all be used to help treat acute lymphocytic leukemia.

Treatment options for acute myelogenous leukemia include chemotherapy, stem cell transplant. Chemotherapy treatment is usually given in two phases called induction and consolidation. Only one type of acute myelogenous leukemia is treated with a third phase which is called the maintenance phase however for all the other types of leukemia central nervous system prophylaxis is a crucial part of treatment. Central nervous system prophylaxis is used to insure the leukemia does not spread to or stay in the cerebrospinal fluid in and around the brain or spinal cord. It is not given for acute myelogenous leukemia because it only spreads to the central nervous system in 5% of people. However, since there still remains a chance of it spreading to the central nervous system it is treated with intrathecal chemotherapy with systemic chemotherapy given directly into the Cerebrospinal fluid. The chemotherapy given directly into the cerebrospinal fluid is given during a lumbar puncture which is a procedure in which a needle is inserted into the lower part of the spinal column or through an ommaya reservoir which is a device surgically implanted beneath the scalp that is used to deliver chemotherapy drugs directly into the cerebrospinal fluid around the brain and spinal cord. Stem cell transplants are given during the first complete remission or after an early first relapse and a second complete remission. Stem cell transplant replaces a person's blood-forming stem cells. A donor lymphocyte infusion can be used to treat acute myelogenous leukemia because before a stem cell transplant the blood cells are removed from the donor’s blood however if a relapse occurs after a stem cell transplant the lymphocytes are given to the person through one or more infusions which is called a donor lymphocyte infusion. Radiation therapy can be used to treat acute myelogenous leukemia in many different ways. It can be given to the whole body which is called total body irradiation to prepare for a stem cell transplant, it can be used to treat a buildup of leukemia cells or blasts outside the bone marrow, relieve pain if the leukemia has spread to an area of bone, or treat acute myelogenous leukemia hat has spread to the central nervous system. Supportive therapy is the last treatment and it is only given to treat the complications that usually happen with treatments for acute myelogenous leukemia and the actual