Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form.
When you're told that you have cancer, it's natural to wonder what may have caused the disease. No one knows the exact causes of leukemia. Doctors seldom know why one person gets leukemia and another doesn't. However, research shows that certain risk factors increase the chance that a person will get this disease.
The risk factors may be different for the different types of leukemia:
- Radiation: People exposed to very high levels of radiation are much more likely than others to get acute myeloid leukemia, chronic myeloid leukemia, or acute lymphocytic leukemia.
- Atomic bomb explosions: Very high levels of radiation have been caused by atomic bomb explosions (such as those in Japan during World War II). People, especially children, who survive atomic bomb explosions are at increased risk of leukemia.
- Radiation therapy: Another source of exposure to high levels of radiation is medical treatment for cancer and other conditions. Radiation therapy can increase the risk of leukemia.
- Diagnostic x-rays: Dental x-rays and other diagnostic x-rays (such as CT scans) expose people to much lower levels of radiation. It's not known yet whether this low level of radiation to children or adults is linked to leukemia. Researchers are studying whether having many x-rays may increase the risk of leukemia. They are also studying whether CT scans during childhood are linked with increased risk of developing leukemia.
- Smoking: Smoking cigarettes increases the risk of acute myeloid leukemia.
- Benzene: Exposure to benzene in the workplace can cause acute myeloid leukemia. It may also cause chronic myeloid leukemia or acute lymphocytic leukemia. Benzene is used widely in the chemical industry. It's also found in cigarette smoke and gasoline.
- Chemotherapy: Cancer patients treated with certain types of cancer-fighting drugs sometimes later get acute myeloid leukemia or acute lymphocytic leukemia. For example, being treated with drugs known as alkylating agents or topoisomerase inhibitors is linked with a small chance of later developing acute leukemia.
- Down syndrome and certain other inherited diseases: Down syndrome and certain other inherited diseases increase the risk of developing acute leukemia.
- Myelodysplastic syndrome and certain other blood disorders: People with certain blood disorders are at increased risk of acute myeloid leukemia.
- Human T-cell leukemia virus type I (HTLV-I): People with HTLV-I infection are at increased risk of a rare type of leukemia known as adult T-cell leukemia. Although the HTLV-I virus may cause this rare disease, adult T-cell leukemia and other types of leukemia are not contagious.
- Family history of leukemia: It's rare for more than one person in a family to have leukemia. When it does happen, it's most likely to involve chronic lymphocytic leukemia. However, only a few people with chronic lymphocytic leukemia have a father, mother, brother, sister, or child who also has the disease.
Having one or more risk factors does not mean that a person will get leukemia. Most people who have risk factors never develop the disease.
Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.
People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.
People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.
Common symptoms of chronic or acute leukemia may include:
- Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)
- Fevers or night sweats
- Frequent infections
- Feeling weak or tired
- Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)
- Swelling or discomfort in the abdomen (from a swollen spleen or liver)
- Weight loss for no known reason
- Pain in the bones or joints
Most often, these symptoms are not due to cancer. An infection or other health problems may also cause these symptoms. Only a doctor can tell for sure.
Anyone with these symptoms should tell the doctor so that problems can be diagnosed and treated as early as possible.
People with leukemia have many treatment options. The options are watchful waiting, chemotherapy, targeted therapy, biological therapy, radiation therapy, and stem cell transplant. If your spleen is enlarged, your doctor may suggest surgery to remove it. Sometimes a combination of these treatments is used.
The choice of treatment depends mainly on the following:
- The type of leukemia (acute or chronic)
- Your age
- Whether leukemia cells were found in your cerebrospinal fluid
It also may depend on certain features of the leukemia cells. Your doctor also considers your symptoms and general health.
People with acute leukemia need to be treated right away. The goal of treatment is to destroy signs of leukemia in the body and make symptoms go away. This is called a remission. After people go into remission, more therapy may be given to prevent a relapse. This type of therapy is called consolidation therapy or maintenance therapy. Many people with acute leukemia can be cured.
If you have chronic leukemia without symptoms, you may not need cancer treatment right away. Your doctor will watch your health closely so that treatment can start when you begin to have symptoms. Not getting cancer treatment right away is called watchful waiting.
When treatment for chronic leukemia is needed, it can often control the disease and its symptoms. People may receive maintenance therapy to help keep the cancer in remission, but chronic leukemia can seldom be cured with chemotherapy. However, stem cell transplants offer some people with chronic leukemia the chance for cure.
Your doctor can describe your treatment choices, the expected results, and the possible side effects. You and your doctor can work together to develop a treatment plan that meets your medical and personal needs.
You may want to talk with your doctor about taking part in a clinical trial, a research study of new treatment methods.
Your doctor may refer you to a specialist, or you may ask for a referral. Specialists who treat leukemia include hematologists, medical oncologists, and radiation oncologists. Pediatric oncologists and hematologists treat childhood leukemia. Your health care team may also include an oncology nurse and a registered dietitian.
Whenever possible, people should be treated at a medical center that has doctors experienced in treating leukemia. If this isn't possible, your doctor may discuss the treatment plan with a specialist at such a center.
Before treatment starts, ask your health care team to explain possible side effects and how treatment may change your normal activities. Because cancer treatments often damage healthy cells and tissues, side effects are common. Side effects may not be the same for each person, and they may change from one treatment session to the next.