But what about when a cancer starts in the blood? You may have known a child who developed leukemia back in the early 1960s. For a two-year-old just learning to walk and talk, the diagnosis was a tragic death sentence. Leukemia continues to take the lives of American children and adults, but there are two pieces of good news:
1) The incidence of leukemia has remained about the same since the early 1950s and
2) Advances in chemotherapy have greatly increased a patient’s odds for long-term survival.
For one type of leukemia, about 90 percent of children attain remission and more than half are cured completely. Leukemia, which literally means “white blood,” involves abnormal growth of white blood cells. White blood cells are necessary to help fight infection, but when there are too many of them, they tend to crowd out red blood cells, which carry oxygen, and platelets, needed to allow blood to clot.
Leukemia is the most common type of childhood cancer, accounting for about 30 percent of cancers in children age 15 and younger. But, believe it or not, leukemia is seen most frequently in adults age 60 and over. This cancer is diagnosed in about 29,000 adults and 2,000 children each year in the United States.
Leukemia can be either acute, meaning that the symptoms worsen very quickly, or chronic. In chronic leukemia, the patient may notice nothing at first and once the symptoms appear, they usually get worse very slowly. Leukemia is also grouped according to the type of white blood cell that is affected by the disease–either lymphoid or myeloid cells.
As a result, there are four basic types of leukemia:
• Acute lymphocytic leukemia-ALL (3,800 cases a year), the kind most likely to affect children,
• Acute myeloid leukemia-AML (10,600 cases a year), which occurs in both children and adults,
• Chronic lymphocytic leukemia-CLL (7,000 cases a year), which is most common in adults age 55 and over and
• Chronic myeloid leukemia-CML (4,400 cases a year), affecting mostly adults.
As with most cancers, there’s usually no clear explanation for why one person gets leukemia, although there are risk factors that include:
• Smoking or use of tobacco products,
• Exposure to high levels of radiation or x-rays,
• Working with chemicals such as benzene or formaldehyde,
• Chemotherapy for another cancer and
• Down syndrome or other diseases caused by abnormal chromosomes.
With acute leukemia, the patient may see a doctor right away for symptoms that are severe but common to many diseases–fevers, night sweats, frequent infections, feeling weak or tired, headache, joint or bone pain, swelling or discomfort in the abdomen (from an enlarged spleen), weight loss and swollen lymph nodes in the neck or armpit. These effects often occur because the abnormal white blood cells are crowding out normal blood cells and interfering with the work they ordinarily perform. Aside from other treatment, the patient may need blood and platelet transfusions to boost immune function and reduce the risk of bleeding and anemia.
Acute leukemia is treated with aggressive chemotherapy for several weeks in a hospital. The patient is usually placed in sterile isolation and cleansed constantly to reduce the risk of infection. Patients with acute lymphocytic leukemia (ALL) usually attain satisfactory remission at this point but may continue to receive low-dose chemotherapy and perhaps radiation therapy for at least a month to be sure the cancer has been wiped out. Maintenance therapy may be continued on and off over a period of months or even years.
While treatment of ALL in children is a major cancer success story, acute myeloid leukemia (AML) does not respond as well to chemotherapy and usually requires bone marrow transplantation. First, the patient’s white blood cell count must be brought under control, either through chemotherapy or leukopheresis, a process that separates cancer cells from the blood. Then the patient’s bone marrow is destroyed through chemotherapy and replaced by compatible marrow from a healthy donor, often a family member.
Until the donor marrow starts producing new blood cells, the patient has virtually no white blood cells and, as a result, is extremely vulnerable to infection–usually for a period of two to six weeks. While bone marrow transplantation entails considerable risk and expense, it often results in remission or cure for AML and difficult-to-treat cases of ALL. Donor registries are a useful means of finding matches for a victim. All who are willing should volunteer to submit a blood sample to check for compatibility.
For chronic leukemia, treatment may not be needed right away, as the doctor carefully monitors signs of the disease and other types of cancer. More than 30 percent of persons with chronic lymphocytic leukemia never need treatment, but they do have an increased risk of developing a second cancer. When symptoms develop, they are usually treated with oral chemotherapy until the disease becomes acute. Interferon can be useful in killing or slowing the growth of white blood cells, but many CLL patients eventually need bone marrow transplantation.
Interferon is one of several biological therapies that work by enabling the patient’s immune system to kill leukemia cells. As with other cancers, radiation therapy is also a useful treatment tool. A recently introduced drug, imatinib mesylate (Gleevec), targets the enzymes which cause cancerous white blood cells to grow out of control. Although it doesn’t cure chronic myeloid leukemia, it keeps the cancer under control for many patients and has dramatically improved the chances of treatment success. An alternative drug is dasatinib (Sprycel).
Contrary to the days when leukemia patients, young and old, routinely died, many today survive and go on to live healthy, productive lives. Leukemia survivors remain vulnerable to infections and to other cancers, however. Good lifetime health habits plus regular medical and dental checkups are essential.
Michelle Herbert Thomas, PharmD, CDE
Clinical Director
Richmond Apothecaries, Inc.
