Each day, 143 Americans are diagnosed with leukemia and 66 die of this type of cancer. Leukemia is a blood cancer that occurs when white blood cells change (mutate) and multiply uncontrollably. Over time, these abnormal cells can crowd out healthy blood cells, leading to the development of leukemia. Leukemia does not discriminate when it comes to sex, age, or race.
In 2015, more than 54,000 American men and women will be diagnosed with this disease, and leukemia causes more deaths than any other cancer among children and young adults under age 20. More than 310,000 Americans are living with leukemia.
Although the cause of most cases of leukemia is not known, some factors have been shown to increase the risk for this cancer.
Cancer treatments, especially very large doses of radiation and certain types of chemotherapy, can cause an increased risk for leukemia.
Repeated exposure to certain chemicals, especially benzene, increases the risk for leukemia. According to the Leukemia & Lymphoma Society, car exhaust and industrial emissions account for 20% of benzene exposure, and 50% of benzene exposure results from smoking tobacco or exposure to tobacco smoke.
Genetic disorders, such as Down syndrome and a family history of leukemia, also increase the risk for this cancer.
Some doctors may suspect leukemia as a result of irregular findings from blood tests done for reasons other than cancer. When this is the case, or if the patient is showing symptoms consistent with leukemia, further tests must be done to confirm the presence of leukemia.
In a physical exam, the doctor will look for signs of anemia (such as pale skin), swollen lymph nodes, and enlargement of the liver and spleen.
Through a blood test, the doctor will determine if the patient has abnormal levels of white blood cells or platelets, which is also consistent with leukemia.
A bone marrow test may also be ordered. This procedure requires the doctor to remove a sample of bone marrow (the spongy tissue found inside bones) from the hip by using a needle. The sample is then tested for leukemia cells. If abnormal cells are present, specialized testing is done on the bone marrow sample to determine the type of leukemia.
Unlike other cancers, there is no standard staging for leukemia. The disease is described as untreated, in remission, or recurrent. However, once diagnosed, leukemia will be classified to aid in treatment planning.
The symptoms of leukemia are vague and often overlooked, resembling symptoms of the f lu and other common illnesses. Common symptoms of leukemia include:
- Fever or chills
- Bone pain and tenderness
- Weight loss
- Swollen lymph nodes
The symptoms of acute leukemia may include bleeding or bruising easily, significant fatigue and paleness, recurrent infections, or poor healing of minor cuts. Because these symptoms are not unique to leukemia, this type of cancer can go undetected for many years.
Types of Leukemia
Leukemia is classified based on the speed of the cancer’s progression and the type of cells that are involved. This classification will determine the course of treatment.
In “acute” leukemia, the disease is worsening very quickly. In “chronic” leukemia, the disease is progressing slowly. This classification is based on whether the abnormal cells are immature or old, and how quickly the abnormal cells are multiplying. Acute leukemia requires immediate and aggressive treatment.
The second classification is determined by looking at the type of white blood cells that are being affected.
“Lymphocytic” leukemia affects lymphatic tissue that makes up the immune system, while “myelogenous” leukemia affects the blood-forming tissue in bone marrow.
Acute lymphocytic leukemia (ALL) is the most common type of leukemia in young children.
Acute myelogenous leukemia (AML) is the leading type of leukemia found in adults.
Chronic leukemia includes chronic myelogenous leukemia (CML) and chronic lymphocytic leukemia (CLL).
According to the National Cancer Institute, the 5-year overall survival rate of patients with leukemia is 58.5%. The goal of leukemia treatment is complete remission, where the patient returns to good health with no evidence of abnormal blood or marrow cells.
For acute leukemia, complete remission lasting 5 years often indicates long-term survival. Some patients with leukemia can now live for a long time with the proper treatment.
There are 3 types of standard treatment for leukemia:
1. Chemotherapy Chemotherapy uses drugs to stop the growth of cancer cells
2. Radiation therapy Radiation therapy kills cancer cells using x-rays
3. Stem-cell transplant A stem-cell transplant is used in conjunction with chemo. Before chemo, stem cells are removed from the blood or bone marrow, frozen, and then replaced in the patient after chemo. The replaced stem cells restore the body’s blood cells that were destroyed during chemo
Researchers are constantly working to uncover new immunotherapy treatments and to develop new drugs that will stop the progression of leukemia. In the past 2 years (starting in late 2013), the FDA approved several new drugs for the treatment of patients with a specific form of leukemia:
- Gazyva (obinutuzumab) was approved in November 2013 for patients with CLL
- Imbruvica (ibrutinib) was approved in February 2014 for patients with CLL, and in July 2014, it received a second approval for patients with CLL and deletion in chromosome 17
- Arzerra (ofatumumab) was approved in April 2014 for CLL, to be used in combination with chlorambucil for previously untreated patients
- Zydelig (idelalisib) was approved in July 2014 for patients with relapsed CLL, meaning that the disease returned after treatment; idelalisib should be used in combination with Rituxan (rituximab), which was approved for CLL a few years earlier. (In July 2014, idelalisib was also approved for patients with 2 types of lymphoma)
- Blincyto (blinatumomab) was approved in December 2014 for patients with Philadelphia chromosome–negative precursor B-cell ALL (known as B-cell ALL), an uncommon form of ALL.
In addition, clinical trials have shown promising results for one type of immunotherapy called chimeric antigen receptor (CAR)-T cell therapy. In this therapy, the patient’s T-cells are removed, genetically modified, and then replaced in the patient to allow the patient’s immune system to kill the leukemia cells. Studies have reported complete remission (no sign of disease) rates of 90% for patients with ALL who receive CAR-T cell therapy.
Leukemia & Lymphoma Society
American Society of Hematology