DEAR DOCTOR K:
My uncle was recently diagnosed with leukemia. I’d like to learn more about it.
Leukemia is a form of cancer that affects the body’s blood cells. Almost every type of cell in our body can turn cancerous, and blood cells are no exception.
Every day, each of us makes millions of new blood cells — red blood cells, white blood cells, and the cells that make platelets (little cell fragments that help blood to clot). Blood cells are made in the marrow (the inside) of bones.
Blood cells have a relatively short life. Red blood cells last about 120 days. That’s why we need to make so many new cells every day. However, when a cell turns cancerous, it doesn’t die. As a result, the number of cells in the bone marrow and in the blood start increasing.
The most common types of leukemia involve one of the two major types of white blood cells: lymphocytes and myelocytes. These cells help the immune system fight off viruses, infections and other invading organisms.
Leukemias arising from lymphocytes are called lymphocytic leukemias. Those arising from myelocytes are called myeloid, or myelogenous, leukemias. Leukemia is either acute (comes on suddenly) or chronic (lasts a long time). There are four major types of leukemia:
- acute lymphocytic leukemia (ALL)
- acute myeloid leukemia (AML)
- chronic lymphocytic leukemia (CLL)
- chronic myeloid leukemia (CML)
People with leukemia often go to the doctor complaining of fever, fatigue, bleeding or sore gums, nosebleeds, frequent bruising, or aching bones or joints. During the physical exam, the doctor may find swollen lymph nodes or an enlarged liver or spleen. Routine blood tests, especially blood cell counts, may be abnormal.
Leukemia treatments — chemotherapy and radiotherapy — target the cancerous cells being produced in bone marrow. Unfortunately, the treatment kills some healthy blood cells along with the cancerous cells. As a result, treatment often severely compromises the body’s ability to fight infection.
For CML, remarkably powerful new drugs called tyrosine kinase inhibitors have become standard therapy. The reason we have these drugs is that we invested in the research that discovered what exactly happens inside a CML cell to turn it cancerous. That discovery led directly to these breakthrough drugs.
Some patients with leukemia can be cured by a bone marrow transplantation. This Nobel Prize-winning treatment has saved thousands of lives and took years of research.
Patients with leukemia today have a much better prognosis than they did when I went to medical school. When I was an intern, I was on duty in the hospital on Christmas Eve. I spent part of that night reading a story to a boy who was dying of acute lymphocytic leukemia (ALL). It was incurable then. All I could do for him was read him a story. He died Christmas Day. Today, more than 80 percent of kids with ALL can be cured.
That’s because — and only because — we the people, through our government and private companies, have invested in medical research.